,,the ,,poetry ,,of ,,science2 ,,or1 ,,studies ,,of ,,the ,,physical ,,phenomena ,,of ,,nature4 ,,by ,,robert ,,hunt1 ,,author ,,of 8,,researches ,,on ,,light20 8,,elementary ,,physics20 8,,panthea1 ,,or ,,the ,,spirit ,,of ,,nature10 ,,etc4 ,,professor ,,of ,,physics1 ,,metropolitan ,,school ,,of ,,science1 ,,etc41 ,,etc4 ,,third ,,edition1 ,,revised ,,and ,,enlarged4 ,,london3 ,,henry ,g4 ,,bohn1 ,,york ,,street1 ,,covent ,,garden4 ,,mdcccliv4 ,from ,shakespeare to ,plato--from the philosophic poet to the poetic philosopher--the transition is easy1 and the road is crowded with illustrations of our present subject4 99 99 99 99 99 ,hast thou ever raised thy mind to the consideration of ,,existence1 in and by itself1 as the mere act of existing8 ,hast thou ever said to thyself1 thoughtfully1 ,,it ,,is6--heedless1 in that moment1 whether it were a man before thee1 or a flower1 or a grain of sand1--without reference1 in short1 to this or that particular mode or form of existence8 ,if thou hast1 indeed1 attained to this1 thou wilt have felt the presence of a mystery1 which must have fixed thy spirit in awe and wonder4 ,coleridge4 ,,london3 ,,wilson and ,,ogilvy1 #eg1 ,skinner ,street4 ,,preface4 ,since #ahdh1 when the 8,poetry of ,science0 was first submitted to the public1 two editions have been exhausted4 ,this1 were proofs required1 would of itself show that there is a large circle of readers to whom the deductions of science have an unfailing interest4 ,beyond this1 it conveys an assurance that every truth1 however abstract it may appear1 has a large popular value if studied in its relations to those generalities which embrace great natural phenomena4 ,with this persuasion the third edition of the 8,poetry of ,science0 has been extended so as to include all the important discoveries which have been made in ,natural ,philosophy to the end of the year #ahec4 ,it is now presented to the world in a new and cheaper form1 in the hope1 that1 with the extension of its circulation1 there may be awakened1 in still larger circles1 a deep and healthful interest in the sciences of which the volume treats4 ,r4 ,h4 ,edinburgh1 ,march #g1 #ahed4 ,,contents4 ,page ,,preface4 iii ,,contents4 v ,,introduction4 ix ,,chapter ,i4 ,,general ,,conditions ,,of ,,matter4 ,its varied ,characters1 and constant change of external ,form--,the ,grain of ,dust1 its ,properties and ,powers--,combinations in inorganic ,masses and in organized ,creations--,our knowledge of ,matter--,theory of ,ultimate ,atoms--,the ,physical ,forces acting on the ,composition of ,masses--,the certainty of the exercise of subtile principles1 which are beyond the reach of experimental ,science #a ,,chapter ,,ii4 ,,motion4 ,are the ,physical ,forces modes of ,motion8--,motion defined--,philosophical ,views of ,motion1 and the ,principles to which it has been referred--,motions of the ,earth and of the ,solar ,system--,visible ,proofs of the ,earth's ,motion on its ,axis--,influence of the proper ,motions of the ,earth on the ,conditions of ,matter--,theory of the ,conversion of ,motion into ,heat1 c4--,the ,physical ,forces regarded as principles independent of ,motion1 although the ,cause and often apparently the ,effects of it #g ,,chapter ,,iii4 ,,gravitation4 ,the ,forms of ,matter--,shape of the ,earth--,probability of the ,mass forming this ,planet having existed in a ,nebulous ,state--,zodiacal ,lights--,comets--,volatilization of ,solid ,matter by ,artificial means--,the principle of ,gravitation--,its ,influence through ,space and within the smallest ,limits--,gravitating powers of the ,planets--,density of the ,earth--,certainty of ,newton's ,law of the ,inverse ,square--,discovery of ,neptune--,state of a ,body relieved from ,gravitation--,experiment explaining ,saturn's ,ring1 c4--,general inference #ba ,,chapter ,,iv4 ,,molecular ,,forces4 ,conditions of ,matter--,variety of organized ,forms--,inorganic ,forms--,all matter reducible to the most simple conditions--,transmutation1 a natural operation--,chemical ,elementary ,principles--,divisibility of ,matter--,atom--,molecules--,particles-- ,molecular ,force includes several ,agencies--,instanced in the ,action of ,heat on ,bodies--,all ,bodies porous--,solution--,mixture--,combinatio n--,centres of ,force--,different ,states of ,matter 7,allotropic ,conditions7--,theories of ,franklin1 pinus1 and ,coulomb--,electrical and ,magnetic ,agencies--,ancient ,notions--,cohesive ,attraction1 c4 #ce ,,chapter ,v4 ,,crystallogenic ,,forces4 ,crystallisation and ,molecular ,force distinguished--,experimental ,proof--,polarity of ,particles forming a ,crystal--,difference between ,organic and ,inorganic ,forms--,decomposition of ,crystals in ,nature--,substitution of ,particles in ,crystals--,pseudomorphism--,crystalline ,form not dependent on ,chemical ,nature--,isomorphism--,dimorphism--,the ories of ,crystallogenic ,attraction--,influence of ,electricity and ,magnetism--,phenomena during ,crystallisation--,can a change of ,form take place in ,primitive ,atoms8--,illustrative ,example of ,crystallisation #ej ,,chapter ,,vi4 ,,heat--,,solar ,,and ,,terrestrial4 ,solar and ,terrestrial ,heat--,position of the ,earth in the ,solar ,system--,heat and ,light associated in the ,sunbeam--,transparency of ,bodies to ,heat--,heating ,powers of the ,coloured ,rays of the ,spectrum--,undulatory ,theory--,conducting ,property of the ,earth's ,crust--,convection--,radiation--,action of the ,atmosphere on ,heat ,rays--,peculiar ,heat ,rays--,absorption and ,radiation of ,heat by dissimilar ,bodies--,changes in the ,constitution of ,solar ,beam--,differences between ,transmitted and ,reflected ,solar ,heat--,phenomena of ,dew--,action of ,solar ,heat of the ,ocean--,circulation of ,heat by the ,atmosphere and the ,ocean--,heat of the ,earth--,mean ,temperature--,central ,heat--,constant ,radiation of ,heat ,rays from all ,bodies--,thermography--,action of ,heat on ,molecular ,arrangements--,sources of ,terrestrial ,heat--,latent ,heat of ,bodies--,animal ,heat--,eremacausis--,spheroidal ,state ,cold--,condensation--,freezing--,theori es of ,heat--,natural ,phenomena--and ,philosophical ,conclusion #fb ,,chapter ,,vii4 ,,light4 ,theories of the ,nature of ,light--,hypotheses of ,newton and ,huygens--,sources of ,light--,the ,sun--,velocity of ,light--,transparency--,dark ,lines of the ,spectrum--,absorption of ,light--,colour--,prismatic ,analysis--,rays of the ,spectrum--,rainbow--,diffraction--,inte rference--,goethe's ,theory--,polarisation--,magnetisation of ,light--,vision--,the ,eye--,analogy--,sound and ,light--,influence of ,light on ,animals and ,vegetables--,phosphorescence arising from several ,causes--,artificial ,light--,its ,colour dependent on ,matter #aah ,,chapter ,,viii4 ,,actinism--,,chemical ,,radiations4 ,the ,sun-ray and its ,powers--,darkening of ,horn ,silver--,niepce's ,discovery--,prismatic ,spectrum--,refrangibility of ,light1 ,heat1 and ,actinism--,daguerre's ,discovery--,photography--,chemical ,effects produced by ,solar ,radiations--,absorption of ,actinism--,phenomena of the ,daguerreotype--,chemical ,change produced upon all ,bodies--,power of ,matter to restore its ,condition--,light protects from ,chemical ,change--,photographs taken in ,darkness--,chemical ,effects of ,light on organized ,forms--,chemical ,effects of ,solar ,heat--,influence of ,actinism on ,electricity--,radiations in ,darkness--,moser's ,discoveries1 c4 #aff ,,chapter ,,ix4 ,,electricity4 ,discovery of ,electrical ,force--,diffused through all ,matter--,what is ,electricity8--,theories--,frictional ,electricity--,conducting ,power of ,bodies--,hypothesis of two ,fluids--,electrical ,images--,galvanic ,electricity--,effects on ,animals--,chemistry of ,galvanic ,battery--,electricity of a ,drop of ,water--,electro-chemical ,action--,electrical ,currents--,thermo-,electricity--,animal ,electricity--,gymnotus--,torpedo--,atmo spheric ,electricity--,lightning ,conductors--,earth's ,magnetism due to ,electrical ,currents--,influence on ,vitality--,animal and ,vegetable ,development--,terrestrial ,currents--,electricity of ,mineral ,veins--,electrotype--,influence of ,heat1 ,light1 and ,actinism on ,electrical ,phenomena #aic ,,chapter ,x4 ,,magnetism4 ,magnetic ,iron--,knowledge of1 by the ,ancients--,artificial ,magnets--,electro-,magnets--,electro-,m agnetism--,magneto- ,electricity--,theories of ,magnetism--,the ,magnetic ,power of soft ,iron and ,steel--,influence of ,heat on ,magnetism--,terrestrial ,magnetism--,declination of the ,compass-needle--,variation of the ,earth's ,magnetism--,magnetic ,poles--,hansteen's ,speculations--,monthly and ,diurnal ,variation--,dip and ,intensity--,thermo-,magnetism--,aurora ,borealis--,magnetic ,storms--,magnetic conditions of ,matter--,diamagnetism1 c4 #bce ,,chapter ,,xi4 ,,chemical ,,forces4 ,nature's ,chemistry--,changes produced by ,chemical ,combination--,atomic ,constitution of ,bodies--,laws of ,combination--,combining ,equivalents--,elective ,affinity--,chemical ,decomposition--,compound ,character of ,chemical ,phenomena--,catalysis or action of ,presence--,transformation of ,organic ,bodies--,organic ,chemistry--,constancy of ,combining ,proportions--,the ,law of ,volumes1 the ,law of ,substitutions1 ,isomeric ,states1 c4 #bgj ,,chapter ,,xii4 ,,chemical ,,phenomena4 ,water--,its ,constituents--,oxygen--,hydrogen--,pero xide of ,hydrogen--,physical ,property of ,water--,ice--,sea ,water--,chlorine--,muriatic ,acid--,iodine--,bromine--,compounds of ,hydrogen with ,carbon--,combustion--,flame--,safety ,lamp--,respiration--,animal ,heat--,the ,atmosphere--,carbonic ,acid--,influence of ,plants on the ,air--,chemical ,phenomena of ,vegetation--,compounds of ,nitrogen--,mineral ,kingdom1 c4 c4 #bie ,,chapter ,,xiii4 ,,time4--,,geological ,,phenomena4 ,time1 an element in ,nature's ,operations--,geological ,science--,its ,facts and ,inferences--,nebular ,hypothesis applied--,primary ,formations--,plutonic and ,metamorphic ,rocks--,transition ,series--,palozoic ,rocks--,commencement of ,organic ,arrangements--,existence of ,phosphoric ,acid in ,plutonic ,rocks--,fossil ,remains--,coal ,formation--,sandstones--,tertiary ,formations--,eocene1 ,miocene1 and ,pliocene ,formations--,progressive changes now apparent--,general ,conclusions--,physics applied in explanation #ccb ,,chapter ,,xiv4 ,,phenomena ,,of ,,vegetable ,,life4 ,psychology of ,flowers--,progress of ,matter towards ,organization--,vital ,force--,spontaneous ,generation--,the ,vegetable ,cell--,simplest ,development of ,organization--,the ,crystal and the ,cell--,primitive ,germ--,progress of ,vegetation--,influence of ,light--,morphology--,germination--,prod uction of ,woody ,fibre--,leaves--,chlorophylle--,decompo sition of ,carbonic ,acid--,influence of ,light1 ,heat1 and ,actinism on the ,phenomena of ,vegetable ,life--,flowers and ,fruits--,etiolation--,changes in the ,sun's ,rays with the ,seasons--,distribution of ,plants--,electrical and ,combined ,physical ,powers #ceg ,,chapter ,,xv4 ,,phenomena ,,of ,,animal ,,life4 ,distinction between the ,kingdoms of ,nature--,progress of ,animal ,life--,sponges--,polypes--,infusoria--, animalcula--,phosphorescent ,animals--,annelidans--,myriapoda--,anim al ,metamorphoses--,fishes--,birds--,mammal ia--,nervous ,system--,animal ,electricity--,chemical ,influences--,influence of ,light on ,animal ,life--,animal ,heat--,mechanical ,action--,nervous ,excitement--,man and the ,animal ,races1 c4 #chc ,,chapter ,,xvi4 ,,general ,,conclusions4 ,the ,changes produced on ,physical ,phenomena by the ,movement of the ,solar ,system considered--,exertion of the ,physical ,forces through the ,celestial ,spaces--,the ,balance of ,powers--,varieties of ,matter--,extension of ,matter--,theory of ,nonentity--,a ,material ,creation an indisputable fact--,advantages of the ,study of ,science--,conclusion #djc ,,index4 #dac ,,bohn',s ,,books4 ,,transcriber',s ,,note4 ,,introduction4 ,the ,true is the ,beautiful4 ,whenever this becomes evident to our senses1 its influences are of a soul-elevating character4 ,the beautiful1 whether it is perceived in the external forms of matter1 associated in the harmonies of light and colour1 appreciated in the modulations of sweet sounds1 or mingled with those influences which are1 as the inner life of creation1 ever appealing to the soul through the vesture which covers all things1 is the natural theme of the poet1 and the chosen study of the philosopher4 ,but1 it will be asked1 where is the relation between the stern labours of science and the ethereal system which constitutes poetry8 ,the fumes of the laboratory1 its alkalies and acids1 the mechanical appliances of the observatory1 its specula and its lenses1 do not appear fitted for a place in the painted bowers of the ,muses4 ,but1 from the labours of the chemist in his cell1--from the multitudinous observations of the astronomer on his tower1--spring truths which the philosopher employs to interpret nature's mysteries1 and which give to the soul of the poet those realities to which he aspires in his high imaginings4 ,science solicits from the material world1 by the persuasion of inductive search1 a development of its elementary principles1 and of the laws which these obey4 ,philosophy strives to apply the discovered facts to the great phenomena of being1--to deduce large generalities from the fragmentary discoveries of severe induction1--and thus to ascend from matter and its properties up to those impulses which stir the whole1 floating1 as it were1 on the confines of sense1 and indicating1 though dimly1 those superior powers which1 more nearly related to infinity1 mysteriously manifest themselves in the phenomena of mind4 ,poetry seizes the facts of the one and the theories of the other2 unites them by a pleasing thought1 which appeals for truth to the most unthinking soul1 and leads the reflective intellect to higher and higher exercises2 it connects common phenomena with exalted ideas2 and1 applying its holiest powers1 it invests the human mind with the sovereign strength of the ,true4 ,truth is the soul of the poet's thought2--truth is the reward of the philosopher's toil2 and their works1 bearing this stamp1 live among men through all time4 ,science at present rejoices in her ministry to the requirements of advancing civilization1 and is content to receive the reward given to applications which increase the comforts of life1 or add to its luxuries4 ,every improvement in the arts or manufactures1 beyond encreasing utilities for society1 has a tendency to elevate the race4 ,science is ever useful in the working days of our week1 but it is not to be neglected on our ,sabbath1--when1 resting from our labours1 it becomes agreeable to contemplate the few truths permitted to our knowledge1 and thus enter into communion as closely as is allowed to finite beings1 with those influences which involve and interpenetrate the earth1 giving to all things ,life1 ,beauty1 and ,divinity4 ,the human mind naturally delights in the discovery of truth2 and even when perverted by the constant operations of prevailing errors1 a glimpse of the ,real comes upon it like the smile of daylight to the sorrowing captive of some dark prison4 ,the ,psychean labours to try man's soul1 and exalt it1 are the search for truth beneath the mysteries which surround creation1--to gather amaranths1 shining with the hues of heaven1 from plains upon which hang1 dark and heavy1 the mists of earth4 ,the poet may pay the debt of nature1--the philosopher may return to the bosom of our common mother1--even their names fade in the passage of time1 like planets blotted out of heaven but the truths they have revealed to man burn on for ever with unextinguishable brightness4 ,truth cannot die2 it passes from mind to mind1 imparting light in its progress1 and constantly renewing its own brightness during its diffusion4 ,the ,true is the ,beautiful2 and the truths revealed to the mind render us capable of perceiving new beauties on the earth4 ,the gladness of truth is like the ringing voice of a joyous child1 and the most remote recesses echo with the cheerful sound4 ,to be for ever true is the ,science of ,poetry1--the revelation of truth is the ,poetry of ,science4 ,man1 a creation endued with mighty faculties1 but a mystery to himself1 stands in the midst of a wonderful world1 and an infinite variety of phenomena arise around him in strange form and magical disposition1 like the phantasma of a restless night4 ,the solid rock obeys a power which brings its congeries of atoms into a thousand shapes1 each one geometrically perfect4 ,its vegetable covering1 in obedience to some external excitation1 developes itself in a curious diversity of forms1 from the exquisitely graceful to the singularly grotesque1 and exhibits properties still more varied and opposed4 ,the animal organism quickened by higher impulses1--powers working within1 and modifying the influence of the external forces1--presents1 from the ,monad to the ,mammoth1 and through every phase of being up to ,man1 a yet more wonderful series of combinations1 and features still more strangely contrasted4 ,lifting our searching gaze into the measureless space beyond our earth1 we find planet bound to planet1 and system chained to system1 all impelled by a universal force to roll in regularity and order around a common centre4 ,the pendulations of the remotest star are communicated through the unseen bond2 and our rocking world obeys the mysterious impulse throughout all those forces which regulate the inorganic combinations of this earth1 and unto which its organic creation is irresistibly compelled to bow4 ,the glorious sun by day1 and the moon and stars in the silence and the mystery of night1 are felt to influence all material nature1 holding the great ,earth bound in a many-stranded cord which cannot be broken4 ,the tidal flow of the vast ocean1 with its variety of animal and vegetable life1 the atmosphere1 bright with light1 obscured by the storm-cloud1 spanned by the rainbow1 or rent with the explosions of electric fire1--attest to the might of these elementary bonds4 ,these are but a few of the great phenomena which play their part around this globe of ours1 exciting men to wonder1 or shaking them with terror4 ,the mind of man1 in its progress towards its higher destiny1 is tasked with the physical earth as a problem1 which1 within the limits of a life1 it must struggle to solve4 ,the intellectual spirit is capable of embracing all finite things4 ,man is gifted with powers for studying the entire circle of visible creation2 and he is equal1 under proper training1 to the task of examining much of the secret machinery which stirs the whole4 ,in dim outshadowing1 earth's first poets1 from the loveliness of external nature1 evoked beautiful spiritualizations4 ,to them the shady forests teemed with arial beings1--the gushing springs rejoiced in fantastic sprites1--the leaping cataracts gleamed with translucent shades1--the cavernous hills were the abodes of genii1--and the earth-girdling ocean was guarded by mysterious forms4 ,such were the creations of the far-searching mind in its early consciousness of the existence of unseen powers4 ,the philosopher picked out his way through the dark and labyrinthine path1 between effects and causes1 and slowly approaching towards the light1 he gathered semblances of the great ,reality1 like a mirage1 beautiful and truthful1 although still but a cloud-reflection of the vast ,unseen4 ,it is thus that the human mind advances from the ,ideal to the ,real1 and that the poet becomes the philosopher1 and the philosopher rises into the poet2 but at the same time as we progress from fable to fact1 much of the soul-sentiment which made the romantic holy1 and gave a noble tone to every aspiration1 is too frequently merged in a cheerless philosophy which clings to the earth1 and reduces the mind to a mechanical condition1 delighting in the accumulation of facts1 regardless of the great laws by which these are regulated1 and the harmony of all ,telluric combinations secured4 ,in science we find the elements of the most exalted poetry2 and in the mysterious workings of the physical forces we discover connections with the illimitable world of thought1--in which mighty minds delight to try their powers1--as strangely complicated1 and as marvellously ordered1 as in the psychological phenomena which have1 almost exclusively1 been the objects of their studies4 ,in the aspect of visible nature1 with its wonderful diversity of form and its charm of colour1 we find the ,beautiful2 and in the operations of these principles1 which are ever active in producing and maintaining the existing conditions of matter1 we discover the ,sublime4 ,the form and colour of a flower may excite our admiration2 but when we come to examine all the phenomena which combine to produce that piece of symmetry and that lovely hue1--to learn the physiological arrangement of its structural parts1--the chemical actions by which its woody fibre and its juices are produced1--and to investigate those laws by which is regulated the power to throw back the white sunbeam from its surface in coloured rays1--our admiration passes to the higher feeling of deep astonishment at the perfection of the processes1 and of reverence for their great ,designer4 ,there are1 indeed1 8tongues in trees20 but science alone can interpret their mysterious whispers1 and in this consists its poetry4 ,to rest content with the bare enunciation of a truth1 is to perform but one half of a task4 ,as each atom of matter is involved in an atmosphere of properties and powers1 which unites it to every mass of the universe1 so each truth1 however common it may be1 is surrounded by impulses which1 being awakened1 pass from soul to soul like musical undulations1 and which will be repeated through the echoes of space1 and prolonged for all eternity4 ,the poetry which springs from the contemplation of the agencies which are actively employed in producing the transformation of matter1 and which is founded upon the truths developed by the aids of science1 should be in no respect inferior to that which has been inspired by the beauty of the individual forms of matter1 and the pleasing character of their combinations4 ,the imaginative view of man and his world--the creations of the romantic mind--have been1 and ever will be1 dwelt on with a soul-absorbing passion4 ,the mystery of our being1 and the mystery of our ceasing to be1 acting upon intelligences which are for ever striving to comprehend the enigma of themselves1 leads by a natural process to a love for the ,ideal4 ,the discovery of those truths which advance the human mind towards that point of knowledge to which all its secret longings tend1 should excite a higher feeling than any mere creation of the fancy1 how beautiful soever it may be4 ,the phenomena of ,reality are more startling than the phantoms of the ,ideal4 ,truth is stranger than fiction4 ,surely many of the discoveries of science which relate to the combinations of matter1 and exhibit results which we could not by any previous efforts of reasoning dare to reckon on1 results which show the admirable balance of the forces of nature1 and the might of their uncontrolled power1 exhibit to our senses subjects for contemplation truly poetic in their character4 ,we tremble when the thunder-cloud bursts in fury above our heads4 ,the poet seizes on the terrors of the storm to add to the interest of his verse4 ,fancy paints a storm-king1 and the genius of romance clothes his demons in lightnings1 and they are heralded by thunders4 ,these wild imaginings have been the delight of mankind2 there is subject for wonder in them3 but is there anything less wonderful in the well-authenticated fact1 the dew-drop which glistens on the flower1 that the tear which trembles on the eye-lid1 holds locked in its transparent cells an amount of electric fire equal to that which is discharged during a storm from a thunder-cloud8 ,in these studies of the effects which are continually presenting themselves to the observing eye1 and of the phenomena of causes1 as far as they are revealed by ,science in its search of the physical earth1 it will be shown that beneath the beautiful vesture of the external world there exists1 like its quickening soul1 a pervading power1 assuming the most varied aspects1 giving to the whole its life and loveliness1 and linking every portion of this material mass in a common bond with some great universal principle beyond our knowledge4 ,whether by the improvement of the powers of the human mind1 man will ever be enabled to embrace within his knowledge the laws which regulate these remote principles1 we are not sufficiently advanced in intelligence to determine4 ,but if admitted even to a clear perception of the theoretical ,power which we regard as regulating the known forces1 we must still see an unknown agency beyond us1 which can only be referred to the ,creator's will4 ,,the ,,poetry ,,of ,,science4 ,,chapter ,i4 ,,general ,,conditions ,,of ,,matter4 ,its varied ,characters1 and constant change of external ,form--,the ,grain of ,dust1 its ,properties and ,powers--,combinations in inorganic ,masses and in organized ,creations--,our knowledge of ,matter--,theory of ,ultimate ,atoms--,the ,physical ,forces acting on the ,composition of ,masses--,the certainty of the exercise of subtile principles1 which are beyond the reach of experimental ,science4 ,the ,physical ,earth presents to us1 in every form of organic and inorganic matter1 an infinite variety of phenomena4 ,if we select specimens of rocks1 either crystalline or stratified1--of metals in any of their various combinations with oxygen1 sulphur1 and other bodies1--of gems glistening with light and glowing with colour1--if we examine the varied forms and hues of the vegetable world1 or the more mysterious animal creations1 we must inevitably come to the conclusion1 long since proclaimed1 and admit that dust they are1 and to dust must they return4 ,whatever permanency may be given to matter1 it is certain that its form is ever in a state of change4 ,the surface of the 8,eternal ,hills0 is worn away by the soft rains which fall to fertilize1 and from their wrecks1 borne by the waters to the ocean1 new continents are forming4 ,the mutations of the old earth may be read upon her rocks and mountains1 and these records of former changes tell us the infallible truth1 that as the present passes into the future1 so will the form of ,earth undergo an important alteration4 ,the same forces which lifted the ,andes and the ,himalayas are still at work1 and from the particles of matter carried from the present lands by the rivers into the sea1 where they subside in stratified masses1 there will1 in the great future1 be raised new worlds1 upon which the work of life will go forward1 and over which will be spread a vast ,intelligence4 ,if we regard the conditions of the beautiful and varied organic covering of the ,earth1 the certainty1 the constancy1 of change is ever before us4 ,vegetable life passes into the animal form1 and both perish to feed the future plant4 ,man1 moving to-day the monarch of a mighty people1 in a few years passes back to his primitive clod1 and that combination of elementary atoms1 which is dignified with the circle of sovereignty and the robe of purple1 after a period may be sought for in the herbage of the fields1 or in the humble flowers of the valley4 ,we have1 then1 this certain truth1--all things visible around us are but aggregations of atoms4 ,from particles of dust1 which under the microscope could scarcely be distinguished one from the other1 are all the varied forms of nature created4 ,this grain of dust1 this particle of sand1 has strange properties and powers4 ,science has discovered some truths1 but still more are hidden within this irregular molecule of matter which we now survey1 than have yet been shadowed in the dreams of our philosophy4 ,how strangely it obeys the impulses of heat--mysterious are the influences of light upon it--electricity wonderfully excites it--and still more curious is the manner in which it obeys the magic of chemical force4 ,these are phenomena which we have seen2 we know them1 and we can reproduce them at our pleasure4 ,we have advanced a little way into the secrets of nature1 and from the spot we have gained1 we look forward with a vision somewhat brightened by our task2 but we discover so much to be yet unknown1 that we learn another truth1--our vast ignorance of many things relating to this grain of dust4 ,it gathers around it other particles2 they cling together1 and each acting upon every other one1 and all of them arranging themselves around the little centre according to some law1 a beautiful crystal results1 the geometric perfection of its form being a source of admiration4 ,it exerts some other powers1 and atom cohering to atom1 obeying the influences of many external radiant forces1 undergoes inexplicable changes1 and the same dust which we find forming the diamond1 aggregates into the lordly tree1--blends to produce the graceful1 scented1 and richly painted flower1--and combines to yield the luxury of fruit4 ,it quickens with yet undiscovered energies2 it moves with life3 dust is stirred by the mysterious excitement of vital force2 and blood and bone1 nerve and muscle1 are the results4 ,forces1 which we cannot by the utmost refinements of our philosophy detect1 direct the whole1 and from the same dust which formed the rock and grew in the tree1 is produced a living and a breathing thing1 capable of receiving a ,divine illumination1 of bearing in its new state the gladness and the glory of a ,soul4 ,these considerations lead us to reflect on the amount of our knowledge4 ,we are led to ask ourselves1 what do we know8 ,we know that the world with all its variety is composed of certain material atoms1 which1 although presented to us in a great variety of forms1 do not in all probability differ very essentially from each other4 ,we know that those atoms obey certain conditions which appear to be dependent upon the influences of motion1 gravitation1 heat1 light1 electricity1 and chemical force4 ,these powers are only known to us by their effects2 we only detect their action by their operations upon matter2 and although we regard the several phenomena which we have discovered1 as the manifestations of different principles1 it is possible they may be but modifications of some one universal power1 of which these are but a few of its modes of action4 ,in examining1 therefore1 the truths which science has revealed to us1 it is advantageous1 for the purpose of fixing the mind to the subject1 that we assume certain conditions as true4 ,these may be stated in a few sentences1 and then1 without wasting a thought upon those metaphysical subtleties which have from time to time perplexed science1 and served to impede the progress of truth1 we shall proceed to examine our knowledge of the phenomena which constantly occur around us4 ,every form1 whether inorganic or organic1 which we can discover within the limits of human search1 is composed of atoms1 which are capable of assuming1 under the influence of certain physical forces1 conditions essential to the physical state of that body of which they constitute a part4#a ,the known forces1 active in producing these conditions1 are modes of motion2 gravitation and aggregation1 heat1 light2 and associated with these1 actinism or chemical radiation2 electricity1 under all its conditions1 whether static or dynamic2 and chemical affinity1 regarded as the result of a separate elementary principle4 ,these forces must be considered as powers capable of acting in perfect independence of each other4 ,they are possibly modifications of one principle2 but this view being an hypothesis1 which1 as yet1 is only supported by loose analogies1 cannot1 without danger1 be received in any explanation which attempts to deal only with the truths of science4 ,we cannot examine the varied phenomena of nature1 without feeling that there must be other and most active principles of a higher order than any detected by science1 to which belong the important operations of vitality1 whether manifested in the plant or the animal4 ,in treating of these1 although speculation cannot be entirely avoided1 it will be employed only so far as it gives any assistance in linking phenomena together4 ,we have to deal with the active agencies which give form and feature to nature--which regulate the harmony and beauty and vigour of life--and upon which depend those grand changes in the conditions of matter1 which must convince us that death is but the commencement of a new state of being4 ,,footnotes3 #a ,sir ,isaac ,newton supposed matter to consist of hard1 impenetrable1 perfectly inelastic atoms4 ,boscovich regarded the constitution of matter differently4 ,the ultimate atom was with him a point surrounded by powers of infinite elasticity4 7,see ,dr4 ,robisons ,mechanical ,philosophy1 for a full explanation of the theory of ,boscovich47 ,the view entertained by ,dr4 ,faraday1 which will be comprehended from one or two short extracts from his valuable and suggestive paper1 claims attention3-- 8,if the view of the constitution of matter already referred to be assumed to be correct--and ,i may be allowed to speak of the particles of matter1 and the space between them 7in water1 or in the vapour of water1 for instance71 as two different things--the space must be taken as the only continuous part1 for the particles are considered as separated by space from each other4 ,space will permeate all masses of matter in every direction like a net1 except that in the place of meshes it will form cells1 isolating each atom from its neighbours1 and itself only being continuous40 ,examining the question of the conducting power of different bodies1 and observing that as space is the only continuous part1 so space1 according to the received view of matter1 must be at one time a conductor1 at others a non-conductor1 it is remarked3 8,it would seem1 therefore1 that1 in accepting the ordinary atomic theory1 space may be proved to be a non-conductor in non-conducting bodies1 and a conductor in conducting bodies2 but the reasoning ends in this--a subversion of that theory altogether2 for1 if space be an insulator1 it cannot exist in conducting bodies2 and if it be a conductor1 it cannot exist in insulating bodies40--,a ,speculation touching ,electric ,conduction1 and the ,nature of ,matter3 by ,michael ,faraday1 ,d4,c4,l41 ,f4,r4,s41 c43 ,philosophical ,magazine1 vol4 xxiv4 ,third ,series4 ,see also ,wollaston1 ,on the ,finite ,extent of the ,atmosphere4--,phil4 ,trans4 #ahbb4 ,young1 ,on the ,essential ,properties of ,matter4--,lectures on ,natural ,philosophy4 ,mossotti1 ,on ,molecular ,action4--,scientific ,memoirs1 vol4 i4 p4 #ddh4 ,,chapter ,,ii4 ,,motion4 ,are the ,physical ,forces modes of ,motion8--,motion defined--,philosophical ,views of ,motion1 and the ,principles to which it has been referred--,motions of the ,earth and of the ,solar ,system--,visible ,proofs of the ,earth's ,motion on its ,axis--,influence of the proper ,motions of the ,earth on the ,conditions of ,matter--,theory of the ,conversion of ,motion into ,heat1 c4--,the ,physical ,forces regarded as principles independent of ,motion1 although the ,cause and often apparently the ,effects of it4 ,many of the most eminent thinkers of the present time are disposed to regard all the active principles of nature as 8modes of motion10--to look upon light1 heat1 electricity1 and even vital force1 as phenomena resulting from 8change of place0 among the particles of matter2 this change1 disturbance1 or motion1 being dependent upon some undefined mover4#b ,the habit of leaving purely inductive examination for the delusive charms of hypothesis--of viewing the material world as a metaphysical bundle of essential properties1 and nothing more--has led some eminent philosophers to struggle with the task of proving that all the wonderful manifestations of the great physical powers of the universe are but modifications of motion1 without the evidence of any antecedent force4#c ,the views of metaphysicians regarding motion involve many subtle considerations which need not at present detain us4 ,we can only consider motion as a change of place in a given mass of matter4 ,now matter cannot effect this of itself1 no change of place being possible without a mover2 and1 consequently1 motion cannot be a property of matter1 in the strict sense in which that term should be accepted4#d ,motion depends upon certain external disturbing and directing forces acting upon all matter2 and1 consequently1 as every mode of action is determined by some excitement external to the body moved1 motion cannot1 philosophically1 be regarded otherwise than as a peculiar affection of matter under determinable conditions4 8,we find10 says ,sir ,isaac ,newton1 8but little motion in the world1 except what plainly flows from either the active principles of nature1 or from the command of the willer40#e ,plato1 ,aristotle1 and the ,pythagoreans1 supposed that throughout all nature an active principle was diffused1 upon which depended all the properties exhibited by matter4 ,this is the same as the 8plastic nature0 of ,cudworth1#f the 8intellectual and artificial fire0 of ,bishop ,berkeley2#g and to these all modes of motion were referred4 ,sir ,isaac ,newton also regards the material universe and its phenomena as dependent upon 8active principles0--for instance1 the cause of gravity--whereby the planets and comets preserve their motions in their orbits1 and all bodies acquire a degree of motion in falling2 and the cause of fomentation--whereby the heart and blood of animals preserve a perpetual warmth and motion--the inner parts of the earth are kept constantly warmed--many bodies burn and shine--and the sun himself burns and shines1 and with his light warms and cheers all things4 ,the earth turns on its axis at the rate of more than #a1jjj miles an hour1 and passes around the sun with the speed of upwards of #fh1jjj miles in the same time4#h ,the earth and the other planets of our system move in ellipses around a common centre3 therefore their motion cannot have been originally communicated merely by the impressed force of projection4 ,two forces1 at least1 must have operated1 one making the planets tend directly to the centre1 and the other impelling them to fly off at a tangent to the curve described4 ,here we have a system of spheres1 held by some power to a great central mass1 around which they revolve with a fearful velocity4 ,nor is this all2 the ,solar ,system itself1 bound by the same mystic chain to an undiscovered centre1 moves towards a point in space at the rate of #cc1eej1jjj geographical miles1 whilst our earth performs one revolution around the sun4#i ,the evidence of the motion of the ,earth around its axis1 as afforded by the swinging of a pendulum or the rotation of a sphere1 is too interesting to be omitted4 ,in mechanical philosophy1 we have two terms of the same general meaning--the conservation of the plane of vibration--and the conservation of the axis of rotation4 ,for the non-scientific reader1 these terms require explanation1 and in endeavouring to simplify this as much as possible1 we must ask the indulgence of the ,mechanical ,philosopher4 ,let us fix in the centre of a small round table an upright rod1 having an arm extending from its top1 to which we can suspend a tolerably heavy weight attached to a string4 ,this is our piece of apparatus3 upon the table draw a chalk line1 along which line we intend our pendulum to swing1 and continuing this line upon the floor1 or by a mark on the wall1 our arrangements are complete4 ,raise steadily the bob of our pendulum1 and set it free1 so that its plane of vibration is along the line which has been marked4 ,as the pendulum is swinging firmly along this line1 slowly and steadily turn the table round4 ,it will then be seen that the pendulum will still vibrate in the direction of the line we have continued onward to the wall1 but that the line on the table is gradually withdrawn from it4 ,if we had no upright1 we might turn the table entirely round1 without in the slightest degree altering the line along which the pendulum performs its oscillations4 ,now1 if from some elevated spot1 say1 from the centre of the dome of ,st4 ,paul's1 a long and heavy pendulum is suspended1 and if on the floor we mark the line along which we set the pendulum free to vibrate1 it will be seen1 as in the experiment with the table1 that the marked line moves away from under the pendulum4 ,it continues to vibrate in the plane it first described1 although the line on the earth's surface continues to move forward by the diurnal rotation around the axis4 ,similar to this is the law of the conservation of the axis of rotation4 ,if a common humming-top1 the spindle of which is its axis of rotation1 is set spinning obliquely1 it will be seen that the axis will continue to point along the line it took at the commencement of motion4 ,by placing a heavy sphere in a lathe1 resting its projecting axial points on some moveable bearings1 and then getting the sphere into extremely rapid motion1 one of the bearings may be removed without the mass falling to the ground4 ,the rapidity of motion changes so constantly and quickly the position of the particles which have a tendency to fall1 that we have motion balanced against the force of gravitation in a striking manner2 and we learn1 from this experiment1 the explanation of the planetary and stellar masses revolving on their axis at a speed sufficient to maintain them without support in space4 ,a mass of matter1 a sphere or a disc1 carefully balanced1 is fixed in gymbals such as we employ for fixing our compass needles1 and it is set by some mechanical contrivance in rapid rotation4 ,the position of the axis of rotation remains unaltered1 although the earth is moving2 and thus1 by this instrument1--called the gyroscope1--we can determine1 as with the pendulum1 the motion of the earth around its axis2 and we learn why1 during its movement around the sun1 its axis is undeviatingly pointed towards one point in space1 marked in our ,heavens as the ,polar ,star4 ,in addition to these great rotations1 the earth is subjected to other motions1 as the precession of the equinoxes and the nutation of its axis4 ,rocking regularly upon a point round which it rapidly revolves1 whilst it progresses onward in its orbit1 like some huge top in tremulous gyration upon the deck of a vast arial ship gliding rapidly through space1 is the earth performing its part in the great law of motion4 ,the rapidity of these impulses1 supposing the powers of the physical forces were for a moment suspended1 would be sufficient to scatter the mass of our planet over space as a mere star-dust4 ,limiting1 as much as possible1 the view which opens upon the mind as we contemplate the adjustments by which this great machine1 our system1 is preserved in all its order and beauty1 let us forget the great movement of the whole through space1 and endeavour to consider the effect of those motions which are directly related to the earth1 as a member of one small group of worlds4 ,we cannot for a moment doubt1 although we have not any experimental proof of the fact1 that the proper motions of the earth materially influence the conditions of the matter of which it is formed4 ,every pair of atoms is1 like a balance1 delicately suspended1 under the constant struggle which arises from the tendency to fly asunder1 induced by one order of forces--centrifugal force--and the efforts of others1 gravitation and cohesion1 to chain them together4 ,the spring is brought to the highest state of tension--one tremor more1 and it would be destroyed4 ,we cannot1 by any comparison with the labours of the most skilful human artisan1 convey an idea of the exquisite perfection of planetary mechanics1 even so far as they have been discovered by the labours of science2 and we must admit that our insight into the vast machinery has been very limited4 ,all we know is the fact that this planet moves in a certain order1 and at a fixed rate1 and that the speed is of itself sufficient to rend the hardest rocks2 yet the delicate down which rests so lightly upon the flower is undisturbed4 ,it is1 therefore1 evident that matter is endued with powers1 by which mass is bound to mass1 and atom to atom2 these powers are not the results of any of the motions which we have examined1 but1 acting in antagonism to them1 they sustain our globe in its present form4 ,are there other motions to which these powers can be referred8 ,we know of none4 ,that absolute rest may not exist among the particles of matter is probable4 ,electrical action1 chemical power1 crystalline aggregation1 the expansive force of heat1 and many other known agencies1 are in constant operation to prevent it4 ,it must1 however1 be remembered1 that each and every atom constituting a mass may be so suspended between the balanced forces1 that it may be regarded as relatively at rest4 ,theory imagines ,motion as producing ,force--a body is moved1 and its mere mechanical change of place is regarded as generating heat2 and hence the refinements of modern science have advanced to the conclusion that motion and heat are convertible4 ,admitting that the material atoms of which this world is formed are never in a state of quiescence1 yet we cannot suppose any gross ponderable particle as capable of moving itself2 but once set in motion1 it may become the secondary cause of motion in other particles4#aj ,the difficulties of the case would appear to have been as follows3--,are heat1 light1 electricity1 c41 material bodies8 ,if they are material bodies--and heat1 for example1 is the cause of motion--must not the calorific matter move itself--or if it be not self-moving1 by what is it moved8 ,if heat is material1 and the primary cause of motion1 then matter must have an innate power of moving2 it can convert itself into active force1 or be at once a cause and an effect1 which can scarcely be regarded as a logical deduction4 ,we move a particle of matter1 and heat is manifested2 the force being continued1 light1 electricity1 and chemical action result2 all1 as appears from a limited view of the phenomena1 arising out of the mechanical force applied to the particle first moved4#aa ,this mechanical force1 it must be remembered1 is external to the body moved1 and is1 in all probability1 set up by the movement of a muscle1 acted upon by nerves1 under the influence of a will4 ,the series of phenomena we have supposed to arise admit of an explanation free of the hypothesis of motion1 and we avoid the dangerous ground of metaphysical speculation1 and the subtleties of that logic which rests upon the immateriality of all creation4 ,this explanation1 it is freely admitted1 is incomplete3 we cannot distinctly correlate each feature of the phenomena1 combine link to link1 and thus form a perfect chain2 but it is sufficiently clear to exhibit what we do know1 and leave the unknown free for unbiassed investigation4 ,each particle1 each atom of that which conveys to our senses the only ideas we have of natural objects--ponderable matter--is involved in1 or interpenetrated by1 those principles which we call heat and electricity1 with probably many others which are unknown to us2 and although these principles or powers are1 according to some law1 bound in statical equilibrium to inert matter1 they are freely developed by an external excitement1 and the disturbance of any one of them1 upsetting the equilibrium1 leaves the other power equally free to be brought under the cognizance of human sense by their effects4 ,when we come to an examination of the influences exerted by these powers upon the physical earth1 the position1 that they must be regarded as the causes of motion rather than the effects of it1 will be further considered4 ,at present it is only necessary to state thus generally the views we entertain of the conditions of matter in connection with the imponderable forces and mechanical powers4 ,the conversion1 as it has been called1 of motion into heat1 in the experiments of ,count ,rumford and ,mr4 ,joule1#ab are only evidences that a certain uniformity exists between the mechanical force applied1 and the amount of heat liberated4 ,it does not appear that we have any proof of the conversion of motion into physical power4 ,it is necessary1 to a satisfactory contemplation of the wonderful properties of matter1 and of the forces regulating the forms of the entire creation1 that we should be content with regarding the elementary bodies which chemistry instructs us form our globe1 as tangible1 ponderable atoms1 having specific and distinguishing properties4 ,that we should1 as far as it is possible for finite minds to do so1 endeavour to conceive the powers or forces--gravitation1 molecular attraction1 electricity1 heat1 light1 and the principle which determines all chemical phenomena--as manifestations of agencies which hold a place between the most subtile form of matter and the hidden principles of vitality1 which is still vastly inferior to the spiritual state1 which reveals itself dimly in psychological phenomena1 and arrives at its sublimity in the ,god of the universe4 ,,footnotes3 #b 8,motion1 therefore1 is a change of rectilinear distance between two points4 ,allowing the accuracy of this definition1 it appears that two points are necessary to constitute motion2 that in all cases1 when we are inquiring whether or no any body or point is in motion1 we must recur to some other point which we can compare with it2 and that if a single atom existed alone in the universe1 it could neither be said to be in motion nor at rest4 8,the space which we call quiescent is in general the earth's surface2 yet we well know1 from astronomical considerations1 that every point of the earth's surface is perpetually in motion1 and that in very various directions3 nor are any material objects accessible to our senses which we can consider as absolutely motionless1 or even as motionless with regard to each other2 since the continual variation of temperature to which all bodies are liable1 and the minute agitations arising from the motion of other bodies with which they are connected1 will always tend to produce some imperceptible changes in their distances40--,lectures on ,natural ,philosophy1 c41 by ,thomas ,young1 ,m4,d4 ,edited by the ,rev4 ,p4 ,kelland4 #ahde4 #c 8,the position which ,i seek to establish in this essay is1 that the various imponderable agencies1 or the affections of matter which constitute the main objects of experimental physics1 viz41 heat1 light1 electricity1 magnetism1 chemical affinity1 and motion1 are all correlative1 or have a reciprocal dependence2--that neither1 taken abstractedly1 can be said to be the essential or proximate cause of the others2 but that either may1 as a force1 produce1 or be convertible into1 the other3--thus heat may mediately or immediately produce electricity1 electricity may produce heat1 and so of the rest4444 ,although strongly inclined to believe that the five other affections of matter1 which ,i have above named1 are1 and will ultimately be1 resolved into modes of motion1 it would be going too far at present to assume their identity with it3 ,i1 therefore1 use the term force1 in reference to them1 as meaning that active force inseparable from matter1 which induces its various changes40--,on the ,correlation of ,physical ,forces1 by ,w4 ,r4 ,,grove1 ,esq41 ,m4,a41 ,f4,r4,s4 #d ,when discussing the hypothesis of ,hobbes--that no body can possibly be moved but by a body contiguous and moved--,boyle asks3-- 8,i demand how there comes to be local motion in the world8 ,for either all the portions of matter that compose the universe have motion belonging to their natures1 which the ,epicureans affirmed for their atoms1 or some parts of matter have this motive power1 and some have not1 or else none of them have it2 but all of them are naturally devoid of motion4 ,if it be granted that motion does naturally belong to all parts of matter1 the dispute is at an end1 the concession quite overthrowing the hypothesis4 8,if ,mr4 ,hobbes should reply that the motion is impressed upon any of the parts of matter by ,god1 he will say that which ,i most readily grant to be true1 but will not serve his turn1 if he would speak congruously with his own hypothesis4 ,for ,i demand whether this ,supreme ,being that the assertion has recourse to1 be a corporeal or an incorporeal substance8 ,if it be the latter1 and yet the efficient cause of motion in bodies1 then it will not be universally true that whatever body is moved is so by a body contiguous and moved4 ,for1 in our supposition1 the bodies that ,god moves1 either immediately or by the intervention of any other immaterial being1 are not moved by a body contiguous1 but by an incorporeal spirit40--,some ,considerations about the ,reconcileableness of ,reason and ,religion3 ,boyle1 vol4 iii4 p4 #ebj4 #e ,boyle has some ingenious speculations on this point3-- 8,that there is local motion in many parts of matter is manifest to sense1 but how matter came by this motion was of old1 and is still1 hotly disputed of3 for the ancient ,corpuscularian philosophers 7whose doctrine in most other points1 though not in all1 we are the most inclinable to71 not acknowledging an author of the universe1 were thereby reduced to make motion congenite to matter1 and consequently coeval with it4 ,but since local motion1 or an endeavour at it1 is not included in the nature of matter1 which is as much matter when it rests as when it moves2 and since we see that the same portion of matter may from motion be reduced to rest1 and after it hath continued at rest1 so long as other bodies do not put it out of that state1 may by external agents be set a moving again2 ,i1 who am not wont to think a man the worse naturalist for not being an atheist1 shall not scruple to say with an eminent philosopher of old1 whom ,i find to have proposed among the ,greeks that opinion 7for the main7 that the excellent ,des ,cartes has revived amongst us1 that the origin of motion in matter is from ,god2 and not only so1 but that thinking it very unfit to be believed1 that matter barely put into motion1 and then left to itself1 should casually constitute this beautiful and orderly world2 ,i think also further1 that the wise ,author of things did1 by establishing the laws of motion among bodies1 and by guiding the first motions of the small parts of matter1 bring them to convene after the manner requisite to compose the world2 and especially did contrive those curious and elaborate engines1 the bodies of living creatures1 endowing most of them with the power of propagating their species40--,considerations and ,experiments touching the ,origin of ,forms and ,qualities3 ,boyle's ,works1 vol4 ii4 p4 #dfj4 ,edinburgh4 #agdd4 #f ,cudworth's ,intellectual ,system4 #g 8,according to the ,pythagoreans and ,platonists1 there is a life infused throughout all things 444 an intellectual and artificial fire--an inward principle1 animal spirit1 or natural life1 producing or forming within1 as art doth without--regulating1 moderating1 and reconciling the various motions1 qualities1 and parts of the mundane system4 ,by virtue of this life1 the great masses are held together in their ordinary courses1 as well as the minutest particles governed in their natural motions1 according to the several laws of attraction1 gravity1 electricity1 magnetism1 and the rest4 ,it is this gives instincts1 teaches the spider her web1 and the bee her honey2--this it is that directs the roots of plants to draw forth juice from the earth1 and the leaves and the cortical vessels to separate and attract such particles of air and elementary fire as suit their respective natures40--,bishop ,berkeley1 ,siris1 ,no4 #bgg4 #h 8,the revolution of the earth is performed in a natural day1 or1 more strictly speaking1 once in #bc;h4 #ef' #d1 and as its mean circumference is #bd1hga miles1 it follows that any point in its equatorial surface has a rotatory motion of more than #a1jjj miles per hour4 ,this velocity must gradually diminish to nothing at either pole4 ,whilst the earth is thus revolving on its axis1 it has a progressive motion in its orbit4 ,if we take the length of the earth's orbit at #fcj1jjj1jjj1 its motion through space must exceed #fh1dij miles in the hour40--,enc4 ,brit4 art4 ,physical ,geography4 #i 8,here then we have the splendid result of the united studies of ,,mm4 ,argelander1 ,o4 ,struve1 and ,peters1 grounded on observations made at the three observatories of ,dorpat1 ,abo1 ,pulkova1 and which is expressed in the following thesis3--,the motion of the solar system in space is directed to a point of the celestial vault situated on the right line which joins the two stars and ,herculis1 at a quarter of the apparent distance of these stars1 reckoning from ,herculis4 ,the velocity of this motion is such1 that the sun1 with all the bodies which depend upon it1 advances annually in the above direction #afbc times the radius of the earth's orbit1 or #cc1eej1jjj geographical miles4 ,the possible error of this last number amounts to #a1gcc1jjj geographical miles1 or to a seventh of the whole value4 ,we may then wager #djj1jjj to #a that the sun has a proper progressive motion1 and #a to #a that it is comprised between the limits of thirty-eight and twenty-nine millions of geographical miles40--,etudes d',astronomie ,stellaire3 ,sur la ,voie ,lacte et sur les ,distances des ,etoiles ,fixes3 ,m4 ,f4 ,w4 ,g4 ,struve4 ,a report addressed to his ,excellency ,m4 ,le ,comte ,ouvaroff2 ,minister of ,public ,instruction and ,president of the ,imperial ,academy of ,sciences at ,st4 ,petersburg4 #aj 8,the first great agent which the analysis of natural phenomena offers to our consideration1 more frequently and prominently than any other1 is force4 ,its effects are either1 #ast1 to counteract the exertion of opposing force1 and thereby to maintain equilibrium2 or1 #bndly1 to produce motion in matter1 8,matter1 or that whatever it be of which all the objects in nature which manifest themselves directly to our senses consist1 presents us with two general qualities1 which at first sight appear to stand in contradiction to each other--activity and inertness4 ,its activity is proved by its power of spontaneously setting other matter in motion1 and of itself obeying their mutual impulse1 and moving under the influence of its own and other force2 inertness1 in refusing to move unless obliged to do so by a force impressed externally1 or mutually exerted between itself and other matter1 and by persisting in its state of motion or rest unless disturbed by some external cause4 ,yet1 in reality1 this contradiction is only apparent4 ,force being the cause1 and motion the effect produced by it on matter1 to say that matter is inert1 or has inertia1 as it is termed1 is only to say that the cause is expended in producing its effect1 and that the same cause cannot 7without renewal7 produce double or triple its own proper effect4 ,in this point of view1 equilibrium may be conceived as a continual production of two opposite effects1 each1 undoing at every instant what the other has done108--,see continuation of the argument in ,herschel's ,discourse on the ,study of ,natural ,philosophy1 page #bbc4 ,in the ,edinburgh ,new ,philosophical ,journal1 vol4 xlv41 will be found a paper by ,dr ,robert ,brown--8,of the sources of motions upon the ,earth1 and of the means by which they are sustained10 which will well repay an attentive perusal1 as pointing to a class of investigation of the highest order1 and containing deductions of the most philosophic description4 #aa ,friction1 it is well known1 generates heat2 by rapidly rubbing two sticks together1 the ,indian produces their ignition2 heat and light being both manifested4 ,under every mechanical disturbance electrical changes can be detected1 and the action of heat in the combustion of the wood is a chemical phenomenon4 #ab ,count ,rumford's experiment consisted in placing a mass of metal in a box of water at a known temperature1 and1 by employing a boring apparatus1 ascertaining carefully the increase of heat after a given number of revolutions4 ,he thus describes his most satisfactory experiment3-- 8,everything being ready1 ,i proceeded to make the experiment ,i had projected1 in the following manner4 ,the hollow cylinder having been previously cleaned out1 and the inside of its bore wiped with a clean towel till it was quite dry1 the square iron bar1 with the blunt steel borer fixed to the end of it1 was put into its place2 the mouth of the bore of the cylinder being closed at the same time by means of the circular piston through the centre of which the iron bar passed4 8,this being done1 the box was put in its place2 and the joinings of the iron rod1 and of the neck of the cylinder with the two ends of the box1 having been made water-tight1 by means of collars of oiled leather1 the box was filled with cold water 7viz41 at the temperature of #fj7 and the machine was put in motion4 ,the result of this beautiful experiment was very striking1 and the pleasure it afforded me amply repaid me for all the trouble ,i had had1 in contriving and arranging the complicated machinery used in making it4 ,the cylinder1 revolving at the rate of about thirty-two times in a minute1 had been in motion but a short time1 when ,i perceived1 by putting my hand into the water and touching the outside of the cylinder1 that heat was generated1 and it was not long before the water which surrounded the cylinder began to be sensibly warm4 ,at the end of one hour1 ,i found1 by plunging a thermometer into the water in the box 7the quantity of which fluid amounted to #ahgg lbs4 avoirdupois1 or #b-a_/d wine gallons71 that its temperature had been raised no less than #dg2 being now #ajg of ,fahrenheit's scale4 ,when thirty minutes more had elapsed1 or one hour and thirty minutes after the machinery had been put in motion1 the heat of the water in the box was #adb4 ,at the end of two hours1 reckoning from the beginning of the experiment1 the temperature of the water was found to be raised to #agh4 ,at two hours twenty minutes it was at #bjj2 and at two hours thirty minutes it actually boiled40--,inquiry concerning the ,source of the ,heat excited by ,friction3 ,philosophical ,transactions1 vol4 lxxxviii4 ,a4,d4 #agih4 8,mr4 ,joule brought a communication on the same subject before the ,british ,association at ,cambridge1 which was afterwards published in the ,philosophical ,magazine1 and from that journal the following notices are extracted3-- 8,the apparatus exhibited before the ,association consisted of a brass paddle-wheel1 working horizontally in a can of water4 ,motion could be communicated to this paddle by means of weights1 pulleys1 c4 ,the paddle moved with great resistance in the can of water1 so that the weights 7each of four pounds7 descended at the slow rate of about one foot per second4 ,the height of the pulleys from the ground was twelve yards1 and consequently when the weights had descended through that distance they had to be wound up again in order to renew the motion of the paddle4 ,after this operation had been repeated sixteen times1 the increase of the temperature of the water was ascertained by means of a very sensible and accurate thermometer4 8,a series of nine experiments was performed in the above manner1 and nine experiments were made in order to eliminate the cooling or heating effects of the atmosphere4 ,after reducing the result to the capacity for heat of a pound of water1 it appeared that for each degree of heat evolved by the friction of water1 a mechanical power equal to that which can raise a weight of #hij lbs4 to the height of one foot1 had been expended4 8,any of your readers who are so fortunate as to reside amid the romantic scenery of ,wales or ,scotland could1 ,i doubt not1 confirm my experiments by trying the temperature of the water at the top and at the bottom of a cascade4 ,if my views be correct1 a fall of #hag feet will of course generate one degree of heat1 and the temperature of the river ,niagara will be raised about one fifth of a degree by its fall of #afj feet40--,relation between ,heat and ,mechanical ,power3 ,philosoph4 ,mag4 vol4 xxvii4 #ahde4 ,,chapter ,,iii4 ,,gravitation4 ,the ,forms of ,matter--,shape of the ,earth--,probability of the ,mass forming this ,planet having existed in a ,nebulous ,state--,zodiacal ,lights--,comets--,volatilization of ,solid ,matter by ,artificial means--,the principle of ,gravitation--,its ,influence through ,space and within the smallest ,limits--,gravitating powers of the ,planets--,density of the ,earth--,certainty of ,newton's ,law of the ,inverse ,square--,discovery of ,neptune--,state of a ,body relieved from ,gravitation--,experiment explaining ,saturn's ,ring1 c4--,general inference4 ,let us suppose the earth--consisting of three conditions of matter2 the solid1 the fluid1 and the ariform--to be set free from that power by which it is retained in its present form of a spheroid flattened at the poles1 but still subject to the influences of its diurnal and annual rotations4 ,agreeably to the law which regulates the conditions of all bodies moving at high velocities1 the consequence of such a state of things would be1 that our planet would instantly spread itself over an enormous area4 ,the waters and even the solid masses of this globe would1 in all probability1 present themselves amidst the other phenomena of space in a highly attenuated state1 revolving in an orbit around the sun1 as a band of nebulous matter1 which might sometimes be rendered sensible to sight by still reflecting solar light1 or by condensation in the form of flights of shooting stars4#ac ,this may be illustrated by experiment4 ,if upon a rapidly revolving disc we place a ball of dust1 it will be almost immediately spread out1 and its particles will arrange themselves in a series of regular curves1 varying with the velocity of the motion4 ,in addition to the disintegration which would arise from the tendency of the atoms to fly from the centre1 the motion1 in space1 of the planetary mass would naturally occasion a trailing out1 and the only degree of uniformity which this orb could1 under these imaginary conditions1 possibly present1 would be derived from the combined effects of motions in different directions4 ,amid the remoter stars1 some remarkable cloud-like appearances are discovered4 ,these nebul1 presenting to the eye of the observer only a gleaming light1 as from some phosphorescent vapour1 were long regarded as indications of such a condition as that which we have just been considering4 ,astronomers saw1 in those mysterious nebul1 a confirmation of their views1 which regarded all the orbs of the firmament as having once been thin sheets of vapour1 which had gradually1 from irregular bodies traversing space1 been slowly condensed about a centre1 and brought within the limits of aggregating agencies1 until1 after the lapse of ages1 they become sphered stars1 moving in harmony amid the bright host of heaven4#ad ,geologists seized on those views with eagerness1 as confirming theoretical conclusions deduced from an examination of the structure of the earth itself1 and explained by them the gradual accretion of atoms into crystalline rocks from a cooling mass4 ,the researches of modern astronomers1 aided by the magnificent instruments of ,lord ,rosse1#ae have1 however1 shown that many of the most remarkable nebul are only clusters of stars2 so remote from us1 that the light from them appears blended into one diffused sheet or luminous film4 ,there are1 however1 the ,magellanic clouds1 and other singular patches of light1 exhibiting changes which can only be explained on the theory of their slow condensation4 ,there is no evidence to disprove the position that world-formation may still be going on2 that a slow and gradual aggregation of particles1 under the influence of laws with which we are acquainted1 may be constantly in progress1 to end1 eventually1 in the formation of a sphere4 ,may we not regard the zodiacal light as the remains of a solar luminiferous atmosphere1 which once embraced the entire system of which it is the centre8#af ,will not the strange changes which have been seen to take place in cometary bodies1 even whilst they were passing near the earth1--as the division of ,biela's comet and the ultimate formation of a second nucleus from the detached portion1--strongly tend to support the probability of the idea that attenuated matter has1 in the progress of time1 been condensed into solid masses1 and that nebulous clouds must still exist in every state of tenuity in the regions of infinite space1#ag which1 in the mysterious processes of world-formation1 will1 eventually1 become stars1 and reflect across the blue immensity of heaven1 in brightness1 that light which is the necessary agent of organisation and all manifestations of beauty8 ,the inferences drawn from a careful study of the condition of our own globe are in favour of the assumption of the existence of nebulous matter4 ,by the processes of art and manufacture1 by the operation of those powers on which organisation and life depend1 solid matter is constantly poured off in such a state that it cannot be detected1 as matter1 by any of the human senses4 ,yet a thousand results1 daily and hourly accumulating as truths around us1 prove that the solid metals1 the gross earths1 and the constituents of animal and vegetable life1 all pass away invisible to us1 and become 8thin air40 ,we know that1 floating around us1 these volatilized bodies exist in some material form1 and numerous experiments in chemistry are calculated to convince us1 that the most attenuated air is capable1 with a slight change of circumstances1 of being converted into the condition of solid masses4 ,hydrogen gas1 the lightest1 the most ethereal of the chemical elements1 dissolves iron and zinc1 arsenic1 sulphur1 and carbon2 and from the transparent combinations thus formed1 we can with facility separate those ponderous bodies4 ,such substances must exist in our own atmosphere2 why not in the regions of space8 ,whether this planet ever floated a mass of nebulous matter1 only known by its dim and filmy light1 or comet-like rushed through space with widely eccentric orbit1 are questions which can only receive the reply of speculative minds4 ,whether the earth and the other members of the ,solar ,system were ever parts of a ,central ,sun1#ah and thrown from it by some mighty convulsion1 though now revolving with all the other masses around that orb1 chained in their circuits by some infinite power1 is beyond the utmost refinements of science to discover4 ,this hypothesis is1 however1 in its sublime conception1 worthy of the master-mind that gave it birth4 ,all we know is1 that our earth is an oblate sphere1 which1 by the effects of its rotation around an axis1 is somewhat enlarged at the equator and flattened at the poles2--that it maintains its regular course around the sun1 in virtue of the operation of two forces1 one of which1 acting constantly1 would eventually draw it into the body of the sun itself2 but that it is opposed by the other1 centrifugal force1 and the varying momentum of the revolving mass2--that the same force acting from the centre of the earth itself1 and from the centre of every particle of its substance1 resolves the whole into a globular form4 ,the principle of ,gravitation#ai is that force which resides in every form of matter1 by which particle is attracted by particle1 and mass by mass1 the less towards the greater4 ,what this may be1 we scarcely dare to speculate4 ,in the vast area of its action1 which opens before the eye of the mind1 we see a power spanning all space1 and linking together every one of those myriads of worlds which spangle the robe of the ,infinite1 and we are compelled to pause4 ,is this principle of gravitation a property of matter1 or is it a power higher than the more tangible forces1 is the question which presses on the mind4 ,if we regard it as a subtile principle pervading all space1 we compel ourselves to look beyond it for another power yet more refined2 and we cannot halt until1 ascending from the limitable to the illimitable1 we resolve gravitation and its governing influences to the centre of all power--the will of the eternal ,creator4 ,science has developed the grand truth1 that it is by the exercise of this all-pervading influence that the earth is retained in its orbit--that the pellucid globe of dew which glistens on the leaf is bound together--that the dbris which float upon the lake accumulate into one mass--that the sea exhibits the phenomena of the tides--and the arial ocean its barometric changes4 ,in all things this force is active1 and throughout nature it is ever present4 ,our knowledge of the laws which it obeys1 enables us to conclude that the sun and distant planets are consolidated masses like this earth4 ,we find that they have gravitating power1 and by comparing this influence with that exerted by the earth1 we are enabled to weigh the mass of one planet against another4 ,in the balance of the astronomer1 it is as easy to poise the remote star1 as it is for the engineer to calculate the weight of the iron tunnel of the ,menai ,straits1 or any other mechanical structure4 ,thus throughout the universe the balance of gravitating force is unerringly sustained4 ,if one of the most remote of those gems of light1 which flicker at midnight in the dark distance of the starry vault1 was1 by any power1 removed from its place1 the disturbance of these delicately balanced mysteries would be felt through all the created systems of worlds4 ,from the peculiarity of the laws which this power called gravity obeys1 it has been inferred that it acts from centres of force2 it is proved that its power diminishes in the inverse ratio of the square of the distance1 and that the gravitating power of every material body is in the direct proportion of its mass4 ,in astronomical calculations we have first to learn the mass of our earth4 ,experiment informs us that the density of our hardest rock is not above #bh2 but from the enormous pressure to which matter must be subjected1 at great depths from the surface1 the weight of the superincumbent mass constantly increasing1 it is quite certain that the earth's density must be far more than this4 ,maskelyne determined the attraction of large masses by a plummet and line on the mountain ,schehallion4#bj ,cavendish1 with exceedingly delicate apparatus1 observed the attraction of masses of known weight and size upon each other4 ,applying the powers of arithmetical calculation1 and the data obtained from the small experiments to the larger phenomena1 ,maskelyne determined the earth's mean density to be #dga1 whilst ,cavendish made it #edh1 but the more recent refined investigations of ,baily have determined it to be #efg4ba ,from data thus obtained by severe inductive experiments and mathematical analyses1 the astronomer1 by observing the deviations of a distant star1 is enabled to determine the influence of those stellar bodies near which it passes1 and1 hence1 to calculate the relative magnitudes of each4 ,the accuracy of the law is in this way put to the severest test1 and the precision of astronomical prediction is the strongest proof of its universality and truth4 ,rolling onward its lonely way1 in the far immensity of our system1 the planet ,uranus was discovered by the elder ,herschel1--so great its distance that its diminished light could scarcely be detected by the most powerful telescopes2 but since its discovery its path has been carefully watched1 and some irregularities noticed4 ,most of these disturbances were referable to known causes2 but a little alteration in its rate of motion observed when the planet was in one portion of its vast orbit was unexplained4 ,convinced of the certainty of ,newton's law1 and having determined that the attraction of known masses was insufficient to produce the disturbance observed1 these deviations were referred to the gravitating influence of a mass beyond the known limits of our ,solar ,system4 ,by the investigations of ,adams in ,england1#bb and ,le ,verrier in ,france1#bc the place of the hypothetical mass was determined1 and its size computed4 ,as a grand confirmation of the great law1 and to the glory of those two far-searching minds1 who do honour to their respective countries and their age1 the hypothesis became a fact1 in the discovery of the planet ,neptune in the place determined by rigorous calculation4 ,astronomy affords other examples of the sublime truth of the law of gravitation1 than which science can afford no more elevated poetry4 ,so completely is all nature locked in the bonds of this infinite power1 that it is no poetic exaggeration to declare1 that the blow which rends any earthly mass is conveyed by successive impulses to every one of the myriads of orbs1 which are even too remote for the reach of telescopic vision4 ,an illustrative experiment must close our consideration of relative operations of rotation and gravitation4 ,we well know that a body in a fluid state would1 if suspended above the earth1 it being at the same time free to take any form1 naturally assume that of a flattened spheroid1 from the action of the mass of the earth upon it3 whereas the force of cohesive attraction acting equally from all sides of a centre1 would1 if uninfluenced1 necessarily produce a perfect sphere4 ,the best method of showing that this would be the case1 is as follows3-- ,alcohol and water are to be mixed together until the fluid is of the same specific gravity as olive oil4 ,if1 when this is effected1 we drop globules of the oil into the mixed fluid1 it will be seen that they take an orbicular form2--and1 of course1 in this experiment the power of the earth's gravitating influence is neutralized4 ,the same drops of oil under any other conditions would be flattened4 ,simple as this illustration is1 it tells much of the wondrous secret of those beautifully balanced forces of cohesion and of gravitation2 and from the prosaic fact we rise to a great philosophical truth4 ,our experiment may lead us yet farther in exemplification of known phenomena4 ,if we pass a steel wire through one of those floating spheres of oil1 and make it revolve rapidly and steadily1 thus imitating the motion of a planet on its axis1 the oil spreads out1 and we have the spheroidal form of our earth4 ,increase the rapidity of this rotation1 and when a certain rate is obtained the oil widens into a disc1 a ring separates itself from a central globe1 and at a distance from it still revolves around it4#bd ,here we have a miniature representation of the ring of ,saturn4 ,this is a suggestive experiment1 the repetition of which1 by reflective minds1 cannot fail to lead to important deductions4 ,the phenomena of cohesion1 of motion1 and gravitation1 are all involved2 and we produce results resembling1 in a striking manner1 the conditions which prevail in the planetary spaces1 under the influence of the same powers4 ,if we take a glass globe1 and having filled it with a fluid of the proper density1 drop into it large and small globules of oil1 we may produce an instructive representation of the stellar vault1 with its beautiful spheres of light revolving in their respective orbits2 and though crossing each other's paths1 still moving in obedience to attracting and repelling forces--onward in perfect harmony4 ,from the centre of our earth to the utmost extremity of the universe--from the infinitely small to the immensely vast--gravitation exerts its force4 ,it is met on all sides by physical powers acting in antagonism to it1 but1 like a ruling spirit1 it restrains them in their wildest moods4 ,the smallest dust which floats upon the wind ,bears this strong impress of the ,eternal ,mind4 ,in mystery round it1 subtile forces roll2 ,and gravitation binds and guides the whole4 ,in every sand1 before the tempest hurl'd1 ,lie locked the powers which regulate a world1 ,and from each atom human thought may rise ,with might to pierce the mysteries of the skies1-- ,to try each force which rules the mighty plan1 ,of moving planets1 or of breathing man2 ,and from the secret wonders of each sod1 ,evoke the truths1 and learn the power of ,god4 ,,footnotes3 #ac ,three hypotheses may be used to account for this most curious phenomenon4 #ast4 ,the body shines by its own light1 and then explodes like a sky-rocket1 breaking into minute fragments too small to be any longer visible to the naked eye4 #bnd4 ,such a body1 having shone by its own light1 suddenly ceases to be luminous4 8,the falling stars and other fiery meteors which are frequently seen at a considerable height in the atmosphere1 and which have received different names according to the variety of their figure and size1 arise from the fermentation of the effluvia of acid and alkaline bodies which float in the atmosphere4 ,when the more subtile parts of the effluvia are burned away1 the viscous and earthy parts become too heavy for the air to support1 and by their gravity fall to the earth40--,keith's ,use of the ,globes4 ,according to ,sir ,humphry ,davy1 in the ,philosophical ,transactions for #ahdg1 8the luminous appearances of shooting stars and meteors cannot be owing to any inflammation of elastic fluids1 but must depend upon the ignition of solid bodies40 #c4 ,the body shines by the reflected light of the sun1 and ceases to be visible by its passing into the earth's shadow1 or1 in other words1 is eclipsed4 ,upon the two former suppositions the fact of the star's disappearance conveys to us no knowledge of its position1 or of its distance from the earth2 and all that can be said is1 that if it be a satellite of the earth1 the great rapidity of its motion involves the necessity of its being at no great distance from the earth's surface--much nearer than the moon2 while the resistance it would encounter in traversing the air would be so great that it is probably without the limits of our atmosphere4 ,sir ,j4 ,w4 ,lubbock leans to the third hypothesis4--,sir ,j4 ,w4 ,lubbock1 ,on ,shooting ,stars3 ,phil4 ,mag4 ,no4 #bac1 p4 #ha4 ,sir ,j4 ,lubbock also published a supplementary paper on the same subject1 in ,no4 #bad1 p4 #agj4 ,mr4 ,j4 ,p4 ,joule entertains an hypothesis with respect to ,shooting ,stars similar to that advocated by ,chladni to account for meteoric stones1 and he reckons the ignition of these miniature planetary bodies by their violent collision with our atmosphere1 to be a remarkable illustration of the doctrine of the equivalency of heat to mechanical power1 or vis viva4 ,if we suppose a meteoric stone of the size of a six-inch cube to enter our atmosphere at the rate of eighteen miles per second of time1 the atmosphere being #a_/ajj of its density at the earth's surface1 the resistance offered to the motion of the stone will in this case be at least #ea1fjj lbs42 and if the stone traverse twenty miles with this amount of resistance1 sufficient heat will thereby be developed to give #a ,fahrenheit to #f1ifg1ihj lbs4 of water4 ,of course by far the largest portion of this heat will be given to the displaced air1 every particle of which will sustain the shock1 whilst only the surface of the stone will be in violent collision with the atmosphere4 ,hence the stone may be considered as placed in a blast of intensely heated air1 the heat being communicated from the surface to the centre by conduction4 ,only a small portion of the heat evolved will therefore be received by the stone2 but if we estimate it at only #a_/ajj it will still be equal to #a ,fahrenheit per #fi1fgi lbs4 of water1 a quantity quite equal to the melting and dissipation of any materials of which it may be composed4--,mr4 ,j4 ,p4 ,joule1 ,on ,shooting ,stars3 ,phil4 ,mag4 ,no4 #baf1 p4 #cdh4 #ad 8,laplace conjectures that in the original condition of the solar system1 the sun revolved upon his axis1 surrounded by an atmosphere which1 in virtue of an excessive heat1 extended far beyond the orbits of all the planets1 the planets as yet having no existence4 ,the heat gradually diminished1 and as the solar atmosphere contracted by cooling1 the rapidity of its rotation increased by the laws of rotatory motion2 and an exterior zone of vapour was detached from the rest1 the central attraction being no longer able to overcome the increased centrifugal force4 ,this zone of vapour might in some cases retain its form1 as we see it in ,saturn's ring2 but more usually the ring of vapour would break into several masses1 and these would generally coalesce into one mass1 which would revolve about the sun10--,whewell's ,bridgewater ,treatise4 ,the following passage is translated by the same author from ,laplace3-- 8,the anterior state 7a state of cloudy brightness7 was itself preceded by other states1 in which the nebulous matter was more and more diffuse1 the nucleus being less and less luminous4 ,we arrive in this manner at a nebulosity so diffuse1 that its existence could scarce be suspected4 ,such is in fact the first state of the nebula which ,herschel carefully observed by means of his telescope40 ,sir ,william ,herschel has the following observations on these remarkable masses3-- 8,the nature of planetary nebul1 which has hitherto been involved in much darkness1 may now be explained with some degree of satisfaction1 since the uniform and very considerable brightness of their apparent disc accords remarkably well with a much condensed1 luminous fluid2 whereas1 to suppose them to consist of clustering stars will not so completely account for the milkiness or soft tint of their light1 to produce which it would be required that the condensation of the stars should be carried to an almost inconceivable degree of accumulation4 8,how far the light that is perpetually emitted from millions of suns may be concerned in this shining fluid1 it might be presumptuous to attempt to determine2 but notwithstanding the inconceivable subtilty of the particles of light1 when the number of the emitting bodies is almost infinitely great1 and the time of the continual emission indefinitely long1 the quantity of emitted particles may well become adequate to the constitution of a shining fluid or luminous matter1 provided a cause can be found that may retain them from flying off1 or reunite them40--,observations on ,nebulous ,stars3 ,philosophical ,transactions1 vol4 lxxxi4 ,a4,d4 #agia4 ,in addition1 the following ,memoirs on the same subject1 by ,sir ,william ,herschel1 have been published in the ,philosophical ,transactions3--,catalogue of #ajjj ,nebul and ,clusters of ,stars1 vol4 lxxvi42 ,catalogue of another #ajjj1 with remarks on the ,heavens1 vol4 lxxix42 ,catalogue of #ejj more1 with remarks as above1 vol4 xcii42 ,of such as have a cometary appearance1 vol4 ci42 ,of planetary nebul1 ibid42 ,of stellar nebul1 ibid42 ,on the sidereal part of the heavens1 and its connection with the nebulous1 vol4 civ42 ,on the relative distances of clusters of nebulous stars1 vol4 cviii4 #ae ,lord ,rosse's beautiful telescopes have been formed upon principles which appear to embrace the best possible conditions for obtaining a reflecting surface which should reflect the greatest quantity of light1 and retain that property little diminished for a length of time4 ,the alloy used for this purpose consists of tin and copper in atomic proportions1 namely1 one atom of tin to four atoms of copper1 or by weight #ehi to #abfd4--,on the ,construction of large ,reflecting ,telescopes3 by ,lord ,rosse4 ,report of the ,fourteenth ,meeting of the ,british ,association1 #ahdd1 p4 #gi4 #af ,the best description of the ,zodiacal ,light occurs in a letter furnished by ,sir ,john ,herschel to the ,times newspaper in ,march1 #ahdc3--8,the zodiacal light1 as its name imports1 invariably appears in the zodiac1 or1 to speak more precisely1 in the plane of the sun's equator1 which is #g inclined to the zodiac1 and which plane1 seen from the sun1 intersects the ecliptic in longitude #gh and #beh1 or so much in advance of the equinoctial points3 in consequence it is seen to the best advantage at1 or a little after1 the equinoxes2 after sunset1 at the spring1 and before sunrise1 at the autumnal equinox2 not only because the direction of its apparent axis lies at those times more nearly perpendicular to the horizon1 but also because at those epochs we are approaching the situation when it is seen most completely in section4 8,at the vernal equinox the appearance of the zodiacal light is that of a pretty broad pyramidal1 or rather lenticular1 body of light1 which begins to be visible as soon as the twilight decays4 ,it is very bright at its lower or broader part near the horizon1 and1 if there be broken clouds about1 often appears like the glow of a distant conflagration1 or of the rising moon1 only less red1 giving rise1 in short1 to amorphous masses of light such as have been noticed by one of your correspondents as possibly appertaining to the comet4 ,at higher altitudes1 its light fades gradually1 and is seldom traceable much beyond the ,pleiades1 which it usually1 however1 attains and involves1 and 7what is most to my present purpose7 its axis at the vernal equinox is always inclined 7to the northward of the equator7 at an angle of between #fj and #gj to the horizon1 and it is most luminous at its base1 resting on the horizon1 where also it is broadest1 occupying1 in fact1 an angular breadth of somewhere about #aj or #ab in ordinary clear weather40 #ag 8,the assumption that the extent of the starry firmament is literally infinite has been made by one of the greatest of astronomers1 the late ,dr4 ,olbers1 the basis of a conclusion that the celestial spaces are1 in some slight degree1 deficient in transparency2 so that all beyond a certain distance is1 and must remain for ever1 unseen2 the geometrical progression of the extinction of light far outrunning the effect of any conceivable increase in the power of our telescopes4 ,were it not so1 it is argued1 every part of the celestial concave ought to shine with the brightness of the solar disc1 since no visual ray could be so directed as not1 in some point or other of its infinite length1 to encounter such a disc40--,edinburgh ,review1 p4 #ahe1 for ,january1 #ahdh2 ,etudes d',astronomie ,stellaire4 #ah ,in the ,astronomische ,nachrichten of ,july1 #ahdf1 appeared a ,memoir by ,m4 ,mdler1 ,die ,centralsonne4 ,the conclusions arrived at by ,mdler may be understood from the following quotation from a ,french translation1 made by ,m4 ,a4 ,gautier1 in the ,archives des ,sciences ,physiques et ,naturelles1 for ,october1 #ahdf3--8,quoiqu'il rsulte de ce qui prcde que la rgion du ciel que j'ai adopte satisfait toutes les conditions poses plus haut1 il n'en est pas moins convenable de la soumettre toutes les preuves possibles4 ,plusieurs essais de combinaisons diffrentes m'ont convaincu qu'on ne pourrait trouver aucun autre point dans le ciel qui pt tenir lieu1 mme d'une manire approche1 que celui que j'ai adopt4 ,on pourrait maintenant m'addresser l'objection que1 si la rgion du ciel o se trouve le centre de gravit de notre systme d'toiles fixes1 est dtermine par ce qui prcde entre certaines limites1 il n'en rsulte pas la ncessit de choisir ,alcyone pour ce centre1 attendu qu'il pourrait bien tomber sur quelqu'autre toile situe dans le groupe ou dans son voisinage4 ,mais outre que c'est tout prs de l que se trouve le groupe le plus brillant et le plus riche en toiles de tout le ciel1 et qu'il ne s'agit point ici d'un point arbitraire situ dans le voisinage peu apparent et qui n'ait rien qui le distingue1 il ne se trouve nul part1 mme dans la rgion voisine1 une aussi exacte concordance des mouvements propres qu'ici1 et ces mouvements correspondent mieux que tous les autres aux conditions tablies plus haut4 ,or si l'on doit considrer ce groupe central1 entre les toiles galement loignes1 on peut prsumer que la plus brillante de beaucoup prsente la plus grande masse4 ,outre cela ,alcyone1 considre optiquement1 est au milieu du groupe des ,pleades2 et son mouvement propre1 dtermin par ,bessel1 est plus exactement en accord avec la moyenne de ceux des autres ,pleades2 ainsi que des toiles de cette rgion jusqu' #aj de distance4 ,je puis donc tablir comme consquence de tout ce qui prcde1 que le groupe des ,pleades est le groupe central de l'ensemble du systme des toiles fixes1 jusqu'aux limites extrieures dtermines par la ,voie ,lacte2 et que ,alcyone est l'toile de ce groupe qui parat tre1 le plus vraisemblablement1 le vrai ,soleil central40 #ai ,see the article ,on ,gravitation1 ,penny ,cyclopdia1 from the pen of the ,astronomer-,royal4 #bj ,delambre dates the commencement of modern astronomical observation in its most perfect form from ,maskelyne1 who was the first who gave what is now called a standard catalogue 7,a4,d4 #agij7 of stars2 that is1 a number of stars observed with such frequency and accuracy1 that their places serve as standard points of the heavens4 ,his suggestion of the ,nautical ,almanack1 and his superintendence of it to the end of his life1 from its first publication in #agfg1 are mentioned in the ,almanack 7vol4 i4 p4 #cfd72 his ,schehallion ,experiment on ,attraction in vol4 iii4 p4 #fi2 and the character of his ,greenwich ,observations in ,greenwich ,observatory in vol4 ii4 p4 #ddb4 #ba ,experiments to determine the ,density of the ,earth4 ,by ,henry ,cavendish1 ,esq41 ,f4,r4,s4 and ,f4,a4,s4--,philosophical ,transactions1 #agih4 #bb ,adams3 ,an ,explanation of the observed irregularities in the motion of ,uranus1 on the hypothesis of disturbance caused by a more distant ,planet4--,appendix to ,nautical ,almanack for #ahea4 #bc ,le ,verrier3 ,premier ,mmoire sur la thorie d',uranus1 ,comptes ,rendus1 vol4 xxi42 ,sur la plante qui produit les anomalies observes dans le mouvement d',uranus4--,ib4 vol4 xxiii4 #bd ,the experiment alluded to is one of a series by ,m4 ,plateau1 who thus describes his arrangement of the fluid3--8,we begin by making a mixture of alcohol and distilled water1 containing a certain excess of alcohol1 so that when submitted to the trial of the test tube it lets the small sphere of oil fall to the bottom rather rapidly4 ,when this point is obtained1 the whole is thrown upon filters1 care being taken to cover the funnels containing these last with plates of glass2 this precaution is taken in order to prevent1 as much as possible1 the evaporation of the alcohol4 ,the alcoholic liquor passes the first through the filters1 ordinarily carrying with it a certain number of very minute spherules of oil ,when the greater part has thus passed1 the spherules become more numerous2 what still remains in the first filters1 namely1 the oil and a residue of alcoholic liquor1 is then thrown into a single filter placed on a new flask4 ,this last filtration takes place much more slowly than the first1 on account of the viscosity of the oil2 it is considerably accelerated by renewing the filter once or twice during the operation4 ,if the funnel has been covered with sufficient care1 the oil will collect into a single mass at the bottom of the flask under a layer of alcoholic liquor40--,on the ,phenomena presented by a free ,liquid ,mass withdrawn from the action of ,gravity4 ,by ,professor ,plateau1 of the ,university of ,ghent4 ,translated from the ,memoirs of the ,royal ,academy of ,brussels1 vol4 xvi42 in the ,scientific ,memoirs1 vol4 iv4 part #ac4 ,,chapter ,,iv4 ,,molecular ,,forces4 ,conditions of ,matter--,variety of organized ,forms--,inorganic ,forms--,all matter reducible to the most simple conditions--,transmutation1 a natural operation--,chemical ,elementary ,principles--,divisibility of ,matter--,atoms--,molecules--,particles- -,molecular ,force includes several ,agencies--,instanced in the ,action of ,heat on ,bodies--,all ,bodies porous--,solution--,mixture--,combinatio n--,centres of ,force--,different ,states of ,matter 7,allotropic ,conditions7--,theories of ,franklin1 pinus1 and ,coulomb--,electrical and ,magnetic ,agencies--,ancient ,notions--,cohesive ,attraction1 c4 ,in contemplating the works of nature1 we cannot but regard1 with feelings of religious admiration1 the infinite variety of forms under which matter is presented to our senses4 ,on every hand the utmost diversity is exhibited2 through all things we trace the most perfect order2 and over all is diffused the charm of beauty4 ,it is the uneducated or depraved alone who find deformities in the creations by which we are surrounded4 ,the three conditions of matter are--the solid1 the fluid1 and the ariform2 and these belong equally to the organic and the inorganic world4 ,in organic nature we have an almost infinite variety of animal form1 presenting developments widely different from each other1 yet in every case suited to the circumstances required by the position which the creature1 occupies in the scale of being4 ,through the entire series1 from the ,polype to the higher order of animals1 even to man1 we find a uniformity in the progress towards perfection1 and a continuity in the series1 which betrays the great secret1 that the mystery of life is the same in all1--a pervading spiritual essence associated with matter1 and modifying it by the master-mechanism of an ,infinite mind4 ,in the vegetable clothing of the surface of the earth1 which fits it for the abode of man and animals--from the conferv of a stagnant pool1 or the lichen of the wind-beaten rocks1 to the lordly oak or towering palm--a singularly beautiful chain of being presents itself to the contemplative mind1 and we cannot but trace the gradual elevation in the scale of organization4 ,in the inorganic world1 where the great phenomena of life are wanting1 we have constantly exhibited the working of powers of a strangely complicated kind4 ,the symmetrical arrangement of crystals--the diversified characters of mineral formations--the systematic aggregations of particles to form masses possessing properties of a peculiar and striking nature--all prove1 that agencies1 which science1 with all its refinements1 has not yet detected1 are unceasingly at work4 ,heat1 electricity1 chemical power--whatever that may be--and the forces of cohesion1 are known to be involved in the production of the forms we see2 but contemplation soon leads to the conviction that these powers are subordinate to others which we know not of4 ,we know only the things belonging to the surface of our planet1 and these but superficially4 ,the geologist traces rock-formations succeeding each other 7from the primary strata holding no traces of organized forms1 through the ,paleozoic series1 in which1 step by step1 the history of animal life is recorded17 to the more recent formations1 teeming with relics1 which1 though allied to some animal types still existing1 are generally such as have passed away4 ,the naturalist searches the earth1 the waters1 and the air1 for their living things2 and the diversity of form1 the variety of condition1 and the perfection of organization which he discovers as belonging to this our epoch--differing from1 indeed bearing but a slight relation to1 those which mark the earth's mutations--exhibit1 in a most striking view1 the endless variety of characters which matter can assume4 ,we are so accustomed to all these phenomena of matter1 that it is with some difficulty we can bend ourselves to the study of the more simple conditions in which it exists4 ,the solid crusts of this telluric sphere--the waters and the atmosphere--the diversified fabrics of the vegetable kingdom--and the still more complicated structures of men and animals--are1 altogether1 but the aggregation of minute particles in accordance with certain fixed laws4 ,by mechanical means all kinds of matter may be reduced to powder1 the fine particles of which would not appear very different from each other1 but each atom has been impressed with properties peculiar to itself1 which man has no power to change4 ,to nature alone belongs the mysterious property of transmutation4 ,the enthusiastic alchemist1 by the agency of physical forces1 dissipates a metal in vapour2 but it remains a metal1 and the same metal still4 ,by the ,hermetic art he breaks up the combination of masses2 but he cannot alter the principles of any one of the elements which form the mass upon which his skill is tried4 ,every atom is invested with properties peculiar to all of its class2 and each one possesses powers1 to which in mute obedience it is compelled1 by which these properties are modified1 and the character of matter varied4 ,what are those properties8 ,do we know anything of those powers8 ,the earth1 so far as we are acquainted with it1 is composed of about sixty principles1 which we call elementary4 ,these are the most simple states to which we can reduce matter1 and from them all the forms of creation yet examined by the chemist are produced4 ,these elementary principles are1 some of them1 permanently gaseous under the ordinary temperature1 and others exist as solid masses2 the difference between the two conditions being regulated1 as it appears1 by the opposing forces of heat and cohesive attraction4 ,matter has been regarded by some as infinitely divisible2 but the known conditions of chemical combinations lead to the conclusion that there are limits beyond which matter cannot be divided4#be ,the theory of atoms having determinate characters1 and possessing symmetric forms1 certainly has the advantage of presenting to the human mind a starting point--a sort of standing ground1--from which it can direct the survey of cosmical phenomena4 ,the metaphysical hypothesis1 which resolves all matter into properties1 and refers all things to ideas1 leaves the mind in a state of uncertainty and bewilderment4 ,adapting the views of ,dumas1 with some modifications1#bf it will be found more satisfactory to regard the ultimate atoms of matter as points beyond the reach of our examination2 which1 according to a law1 determined by the influences of the so-called imponderable forces1 unite to form molecules4 ,again1 these molecules combine to form the particles of the mass which we may regard as the limit of mechanical division4 ,the particles of solid bodies are solid1 those of fluids fluid1 and those of gaseous bodies are themselves ariform2 but it does not follow that the molecules of any body should be necessarily solid1 fluid1 or ariform1 from the circumstance of their having formed the particles of a body in one of these states4 ,as this planet--a molecule in space--is formed of aggregated atoms1 and enveloped by its own physical agencies--and as it is involved in the infinitely extending influences of other planetary molecules1 and thus forms part of a system--so the molecules of any mass are grouped into a system or particle1 which possesses the great characteristic features of the whole4 ,in an ariform body the particles are in a state of extreme tenuity1 the molecules being themselves1 by the influence of some repulsive force1 just on the verge where cohesion exerts its decaying power4 ,in fluid bodies the attenuation of the particles is less--the particles and also the molecules are nearer together1--whereas1 in the solid body1 the forces of cohesion are most strongly exerted1 and all the molecular conditions brought more powerfully into action4 ,under the term molecular force1 we include several agencies1--not alike in the phenomena which they exhibit1 but which are all-powerful in producing the general characteristics of bodies4 ,these require a somewhat close examination4 ,all the particles of even a solid mass may be brought under conditions on which they are free to move4 ,by heat we can increase the length and thickness of a bar of iron1 or any other metal1 and at length produce the fluid state1--a melted metal flows as freely as water in a stream4 ,fluids1 and gases in like manner obey the dispersive influence of caloric4 ,from these and other analogous results we learn that all bodies have a greater or less degree of porosity4 ,the distance at which the particles of fluid bodies are maintained is strikingly proved by the fact1 that hydrated salts dissolved in water occupy no more space than that which is equal to the water contained in the crystalline body2 while anhydrous salts dissolve without at all increasing the bulk of the fluid4 ,all the solid matter of the salt must1 in these cases1 it would appear1 go to fill up the interstitial spaces which we suppose to exist in the liquid4#bg ,the conditions which regulate the solubility of bodies1 and the power of solution1 regarded either as a mechanical or a chemical process1 are very obscure4 ,we might be led to suppose1 that those bodies possessing the largest amount of unoccupied space were capable of holding the greatest quantity of soluble matter dissolved4 ,this1 however1 is far from being the case1 the denser fluids generally having the greatest solvent power4 ,the peculiar manner in which hydrogen gas appears to dissolve solid substances1--as iron1 potassium1 sodium1 sulphur1 phosphorus1 selenium1 and arsenic1 may be explained by regarding the results as a manifestation of the powers of chemical affinity over the forms of bodies4 ,in like manner1 the solution of salt in water1 or the mixture of alcohol in that fluid1 may be viewed as chemical phenomena1 although usually considered as simple cases of solution or mixture3 alterations of temperature and other physical changes taking place in either4 ,if two masses of metal1--either tin and copper1 for example1--are melted and combined1 the united mass will not equal the bulk of the two masses4 ,if a pint measure of oil of vitriol and an equal quantity of water are mixed together1 the combined fluids will not fill a two pint measure4#bh ,in these instances a large quantity of heat is rendered sensible1 as if it had been squeezed out by the force with which the particles combined1 from interstices1 which were filled with1 what we may be allowed to call1 an atmosphere of heat4 ,hence we conclude that1 amongst the influences determining the molecular constitution of a body1 heat performs an important part4 ,all these facts go to prove that the atoms which form the compound body1 whatever may be its character1 are disposed of as so many centres of force1 which act by influences of a peculiar character upon each other4 ,that these influences are dependent upon known physical forces is certain2 but the laws by which the powers of the ultimate atom are altered remain still unknown4 ,in the great operations of nature1 changes are produced which we cannot understand1 and variations of condition do certainly occur1 which may be regarded as instances of transmutation4 ,amongst others1 we may adduce the different states in which we know carbon to exist4 ,we have the diamond with its beautiful light-refracting property1 its hardness and high specific gravity1 capable of being converted into graphite and coke4#bi ,charcoal1 graphite1 and the diamond1 are totally unlike each other1 yet we know they are each composed of the same atoms4 ,charcoal is a black irregular substance1 light1 and readily inflammable2 graphite is crystallizable2 but the forms of its crystals cannot be referred to those of the diamond1 and it burns with difficulty4 ,the diamond occurs in the most regular and beautifully transparent forms2 and it can be burned only at the highest artificial temperatures4 ,we are1 however1 convinced by experiment that the brilliant and transparent gem is made up of the same atoms as those which go to form the dull black mass of charcoal4 ,from diamonds1 as is above stated1 coke has been formed by the heat of the voltaic battery1 and recent experiments have proved that the volatilized carbon constantly passing off from one of the poles of a sufficiently powerful battery1 is deposited in a crystalline powder1 possessing most of the properties1 as it regards hardness1 c4 of true diamond dust4 ,what is the mystery of this8 ,we know not4 ,the peculiar conditions have been the subjects of anxious study2 but science has not yet let in a ray of light upon the mystery4 ,that a different state--it has been called an allotropic condition--is often induced in the same class of atoms is certain2 and hence the variety of the resulting compounds4 ,to continue our illustrations with carbon--may not its combinations1 in uniform proportions with oxygen and hydrogen1#cj owe their differences to some allotropic change in the ultimate atoms of this element4 ,we know that silicon--the metallic base of flint--is capable of assuming two or more different states2 and that sulphur1 selenium1 phosphorus1 and arsenic1 are susceptible of these remarkable changes in which1 without the slightest variation in the chemical character1 a complete change in the physical condition is produced4 ,copper1 iron1 tin1 and manganese1 are known to exist in at least two states of physical dissimilarity1 and many of the rarer metals exhibit the same peculiarity4#ca ,hence1 may we not infer that some of those substances1 which we now term elementary1 are but altered conditions of the same element8 ,the resemblance between many of those bodies strengthens the supposition4 ,iridium and platinum1--iron and nickel1--chlorine1 bromine1 iodine1 and probably fluorine1--are good examples of these similarities1 although these bodies are all distinguished by physical and chemical differences4 ,the light-refracting gem1 which glistens on the neck of beauty1 and is valued for its transparency1 differs only from the rude lump of coke in its molecular arrangement4 ,chemistry teaches us that we may1 without producing any disarrangement of the affinities1 but by merely setting up molecular disturbance1 effect decided changes1 as is strikingly shown in the colour of iodide of mercury changing from red to yellow under slight influences of heat1 and back again to red by a gentle mechanical disturbance4 ,by a slight change1 merely molecular1 iron may be made to resemble platinum in its physical properties4#cb ,an iron wire plunged into nitric acid is attacked by the acid with violence2 but if one extremity of the wire is heated in the flame of a spirit lamp1 such a change of state is produced throughout the entire length of the wire1 that if it be now plunged into nitric acid no effect is produced upon it4 ,on studying this question1 we find good reason for supposing that bodies which1 though physically different1 resemble each other in some of their properties1 iodine1 bromine1 c41 are the results of different allotropic conditions which have been impressed upon the ultimate atoms1 similar to those observed in the substances named4 ,this hypothesis appears to be more in accordance with the great principles which we must conceive guided the labours of an ,infinite ,mind1 than that which supposes a vast number of individual creations4 ,it will be seen in the sequel that light1 heat1 electricity1 and chemical action1 have the power of producing yet more striking changes in the forms of bodies4 ,is it not probable that1 according to the operations of these agents1 either combined or separate1 acting over different spaces of time1 and under varying circumstances1 in relation to the molecular forces1 all those allotropic states may be produced8 ,hence bodies may be discovered1 which1--from the imperfections of science1--resisting our means of analysis1 must1 for a time1 be regarded as new elements1 whereas they are possibly only altered states of the same substance4 ,the experiments of ,faraday and of ,plcker prove that all matter exists in certain polar conditions1 having powers of mutual attraction and repulsion4#cc ,are the molecular forces1 so called1 to be referred to any of those powers which are involved in the general term magnetic-polarity8 ,are they not probably the result of some ultimate principle of which these properties are but the modified manifestations8 ,these questions will now be generally answered in favour of magnetism2 but in our ignorance we should pause2 the next generation will without doubt find another solution for the problem4 ,franklin supposed the ultimate atoms of bodies to be surrounded by a subtile fluid or ether1 which they have the power of condensing upon their surfaces with great force--and we have experiments showing that this is probable#cd--whilst he regarded the atoms of the ether itself as mutually repellent1 thus establishing an equilibrium of forces4 pinus reduced the hypothesis of ,franklin to a mathematical theory2 and ,coulomb proved that the force with which the repulsion of the ethereal atoms and the attraction of the material molecules are produced1 is1 like universal attraction1--to whatever power that may be due1--regulated by the law of the inverse ratio of the square of the distance4 ,these views are found1 upon minute examination1 to hold true to the phenomena with which inductive science has made us acquainted2 and the striking manner in which1 when submitted to the rigorous investigations of geometers1 they agree with known conditions of electricity1 appears certainly to favour the opinion that this power may be materially connected with these molecular arrangements4 ,many of the phenomena which are connected with the magnetic influences also bear in a remarkable manner upon this inquiry4 ,but1 without the necessary proof of direct experimental evidence1 it were as unphilosophical to refer the binding together of the molecules of matter to the agency of electricity1 as it would be to adopt the theory of the hooked atoms of ,epicurus1 or the astrological dream of the sympathies of matter4#ce ,science1 however1 enables us to infer with safety that the mechanical powers which regulate the constitution of a cube of marble1 or a granite mountain1 are of a similar order to those which determine the earth's relation to the other planets in the solar system1 and that solar system itself a unit1 in the immensity of space1 to the myriads of suns which spangle the stellar vault4 ,in fine1 cohesion1 or the attraction of aggregation1 is a power employed in binding particle to particle4 ,to cohesion1 we find we have heat opposed as a repellent force2 and the mysterious operations of those electrical phenomena1 generally referred to as polar forces1 are constantly1 it is certain1 interfering with its powers4 ,in addition1 we have seen that in nature there exists an agency which is capable of changing the constitution of the ultimate atoms1 and of thus giving variety to each resulting mass4 ,what this power may be1 our science cannot tell2 but our reason leads us1 with firm conviction1 to the belief that it is a principle which is1 beyond all others in its subtile influences which equally universal with1 appears to rise superior to gravitation2 and which1 like a spirituality1 shadows forth to our dwarf conceptions the immensity of the divine power of the omniscient ,creator4 ,the molecular forces involve a consideration of all the known physical powers1 the study of which1 in their operations on matter1 will engage our attention4 ,but it is pleasant to learn1 as we advance step by step in our examination of the phenomena of creation1 that we may study the grand in what externally appears the simple1 and learn1 in the mysteries of a particle1 the high truths which science has to tell of a planet4 ,it may appear that the forces of gravitation and cohesion are regarded as identical4 ,many phenomena1 which we are enabled to reach by the refinements of inductive inquiry1 certainly present to us a striking similarity in the laws which regulate the operations of these powers2 but it must be remembered that their identity is not established4 ,so far from this1 we know the law of gravitating force4 ,newton determined with surprising accuracy1 that the action of this power diminishes with the distance as the universe square1 but cohesive force is exerted only at such distances that it is impossible to determine whether or not it is subjected to the same law4 ,to quote the words of ,young3 8,the whole of our inquiries respecting the intimate nature of forces of any kind must be considered merely as speculative amusements1 which are of no further utility than as they make our views more general1 and assist our experimental investigations40#cf ,,footnotes3 #be 8,the divisibility of matter is great beyond the power of imagination1 but we have no reason for asserting that it is infinite2 for the demonstrations which have sometimes been adduced in favour of this opinion are obviously applicable to space only4 ,the infinite divisibility of space seems to be essential to the conception that we have of its nature1 and it may be strictly demonstrated that it is mathematically possible to draw an infinite number of circles between any given circle and its tangent1 none of which shall touch either of them except at the general point of contact2 and that a ship following always the same oblique course with respect to the meridian1--for example1 sailing north-eastwards1--would continue perpetually to approach the pole without ever completely reaching it4 ,but when we inquire into the truth of the old maxim of the schools1 that all matter is infinitely divisible1 we are by no means able to decide so positively4 ,newton observes that it is doubtful whether any human means may be sufficient to separate the particles of matter beyond a certain limit2 and it is not impossible that there may be some constitution of atoms1 or single corpuscles1 on which their properties1 as matter1 depend1 and which would be destroyed if the units were further divided2 but it appears to be more probable that there are no such atoms1 and even if there are1 it is almost certain that matter is never thus annihilated in the common course of matter40--,the ,essential ,properties of ,matter3 ,young's ,natural ,philosophy2 ed4 by ,rev4 ,p4 ,kelland4 #bf 8,two very different hypotheses have been formed to explain the nature of matter1 or the mode of its formation2 the one known as the atomic theory1 the other1 the dynamic4 ,the founder of the former and earlier was ,leucippus3 he considered the basis of all bodies to be extremely fine particles1 differing in form and nature1 which he supposed to be dispersed through space1 and to which his follower ,epicurus first gave the name of atoms4 ,to these atoms he attributed a rectilinear motion1 in consequence of which such as are homogeneous united1 whilst the lighter were dispersed through space4 ,the author of the second hypothesis was the famous ,kant4 ,he imagined all matter existed1 or was originated1 by two antagonist and mutually counteracting principles1 which he called attraction and repulsion1 all the predicates of which he referred to motion4 ,most modern philosophers1 and foremost amongst them ,ampre and ,poisson1 have adopted an hypothesis combining the features of both the preceding4 ,they regarded the atoms as data1 deriving their origin from the ,deity as the first cause1 and consider their innate attractive and repulsive force as a necessary condition to their combination in bodies4 ,the main features of this hypothesis are borrowed from ,aristotle1 inasmuch as he supposed the basis of all bodies to be the four elements known to the ancients1 the particles of which1 endued with certain powers1 constituted bodies4 ,according to ,ampre1 all bodies consist of equal particles1 and they again of molecules that1 up to a certain distance1 attract each other4 ,their distance from each other he supposed to be regulated by the intensity of the attractive and repulsive forces1 the latter of which preponderates40--,peschel's ,elements of ,physics2 translated by ,e4 ,west1 #ahde4 #bg ,this was first proved by the researches of ,dr4 ,dalton3 the subject will be again alluded to under the consideration of atomic volumes4 #bh ,these peculiar phenomena may be studied advantageously in the works of most of the eminent ,european chemists4 ,in our own language the reader is referred to ,dr4 ,thompson's ,outline of the ,sciences of ,heat and ,electricity1 #bnd edition2 ,brande's ,manual of ,chemistry--,art4 ,specific ,heat2 ,graham's ,elements of ,chemistry2 and ,daniell's ,introduction to the ,study of ,chemical ,philosophy4 #bi ,the conversion of the diamond into graphite and coke was first effected by the agency of the galvanic arc of flame1 by ,m4 ,jaquelini1 and communicated to the ,academy of ,sciences in #ahdg1 in a ,memoir entitled1 ,de l'action calorifique de la pile de ,bunsen1 du chalumeau gaz oxygne et hydrogne sur le carbon pur1 artificiel et naturel4 ,see ,comptes ,rendus1 #ahdg1 vol4 xxiv4 p4 #ajej2 also ,report of the ,british ,association1 for #ahdg1 7,transactions of ,sections7 p4 #ej4 #cj 8,in the annual report on the progress of chemistry1 presented to the ,royal ,academy of ,stockholm1 in ,march #ahdj1 ,i have proposed to designate by the term allotropic state1 that dissimilar condition which is observed in certain elements1 and long known examples of which are found in the different forms of carbon1 as graphite and diamond4 8,although these dissimilar conditions1 which ,i have here called allotropic1 have long since attracted attention in one or two elements1 still they have been regarded as exceptions to the general rule4 ,it is at present my object to show that they are not so rare2 that it is probably rather a general property of the elements to appear in different allotropic conditions2 and that although we have hitherto been unable to obtain several of the elements when uncombined in their allotropic states1 still their compounds indicate the same with tolerable distinctness40--,berzelius on the ,allotropy of the ,elementary ,bodies1 c43 ,poggendorff's ,annalen1 #ahdd4 ,scientific ,memoirs1 vol4 iv4 p4 #bdj4 #ca 8,copper1 when reduced by hydrogen at a heat below that of redness1 on exposure to air soon becomes converted throughout its mass into protoxide2 and when it is triturated for some time with an equivalent quantity of sulphur1 it combines with it according to ,bttcher's experiments1 producing flame1 and forming sulphuret of copper4 ,if1 however1 the copper be reduced by hydrogen at a red heat1 still considerably below the temperature at which it softens and begins to melt1 it remains for years unchanged by exposure to air1 and cannot be made to combine with sulphur without the application of heat4 ,iron1 cobalt1 and nickel1 when reduced by hydrogen below a red heat1 inflame after they have cooled1 if exposed to the air2 and if they are immediately placed in water to avoid their taking fire1 they inflame when they are again removed1 and have become nearly dry4 ,if we compare this behaviour with that of iron reduced by heat1 and with iron in that state in which it forms the conductor of a galvanic current without becoming oxidized1 it would appear that these peculiarities depended upon something more than a difference of mechanical condition40--,berzelius on the ,allotropy of ,elementary ,bodies4 ,see ,on the ,isomeric ,conditions of the ,peroxide of ,tin3 by ,prof4 ,h4 ,rose4--,chemical ,gazette1 ,oct4 #ahdh4 #cb ,on this curious subject1 and its history1 see ,bergman's ,dissert4 de ,phlog4 quantitate in ,metallis1 #agfd4 ,kirwan1 ,on the ,attractive ,powers of ,mineral ,acids3 ,philosophical ,transactions4 ,kier's ,experiments and ,observations on the ,dissolution of ,metals in ,acids3 ,phil4 ,trans4 #agij4 ,from these valuable papers it will be seen that the peculiar states of iron had already attracted attention1 particularly those 8inactive conditions0 noticed in a 8,note sur la ,manire d'agir de l',acide nitrique sur le ,fer1 par ,j4 ,f4 ,w4 ,herschel10 ,aug4 #ahcc2 and previously indicated by ,m4 ,h4 ,braconnot1 ,sur quelques ,proprits de l',acide nitrique1 ,annales de ,chimie1 vol4 lii4 p4 #ed4 ,reference should also be made to the ,memoirs of ,sir ,john ,herschel1 ,on the ,action of the ,rays of the ,solar ,spectrum on ,vegetable ,colours1 c43 ,phil4 ,trans4 vol4 cxxxiii4 p4 #bba2 and ,on the ,separation of ,iron from other ,metals3 ,phil4 ,trans4 vol4 cxi4 p4 #bic2 and several papers by ,schnbein1 in the ,philosophical ,magazine1 from #ahcg4 #cc ,faraday1 in his memoir ,on new ,magnetic ,actions1 and on the ,magnetic ,conditions of all ,matter1 says3--8,by the exertion of this new condition of force1 the body moved may pass either along the magnetic lines or across them1 and it may move along or across them in either or any direction1 so that two portions of matter1 simultaneously subject to this power1 may be made to approach each other as if they were mutually attracted1 or recede as if mutually repelled4 ,all the phenomena resolve themselves into this1 that a portion of such matter1 when under magnetic action1 tends to move from stronger to weaker places or points of force4 ,when the substance is surrounded by lines of magnetic force of equal power on all sides1 it does not tend to move1 and is then in marked contradistinction with a linear current of electricity under the same circumstances40--,phil4 ,trans4 for #ahdf1 vol4 cxxxvii4 #cd ,new ,experiments and ,observations on ,electricity made at ,philadelphia1 in ,america4--,addressed to ,mr4 ,collinson1 from #agdg to #aged4 ,by ,benjamin ,franklin4 ,of these ,priestley remarks3--8,it is not easy to say whether we are most pleased with the simplicity and perspicuity with which the author proposes every hypothesis of his own1 or the noble frankness with which he relates his mistakes1 when they were corrected by subsequent experiments40 #ce 8,the atomic philosophy of ,epicurus1 in its mere physical contemplation1 allows of nothing but matter and space1 which are equally infinite and unbounded1 which have equally existed from all eternity1 and from different combinations of which every visible form is created4 ,these elementary principles have no common property with each other2 for whatever matter is1 that space is the reverse of2 and whatever space is1 matter is the contrary to4 ,the actual solid part of all bodies1 therefore1 are matter1 their actual pores space1 and the parts which are not altogether solid1 but an intermixture of solidity and pore1 are space and matter combined4 8,the infinite groups of atoms1 flying through all time and space in different directions and under different laws1 have interchangeably tried and exhibited every possible mode of rencounter3 sometimes repelled from each other by concussion1 and sometimes adhering to each other from their own jagged or pointed construction1 or from the casual interstices which two or more connected atoms must produce1 and which may be just adapted to those of other figures1--as globular1 oval1 or square4 ,hence the origin of compound and visible bodies2 hence the origin of large masses of matter2 hence1 eventually1 the origin of the world itself40--,dr4 ,good's ,book of ,nature4 #cf ,young's ,lectures on ,natural ,philosophy and the ,mechanical ,arts4 ,lecture #di1 ,on the ,essential ,properties of ,matter4 ,,chapter ,v4 ,,crystallogenic ,,forces4 ,crystallisation and ,molecular ,force distinguished--,experimental ,proof--,polarity of ,particles forming a ,crystal--,difference between ,organic and ,inorganic ,forms--,decomposition of ,crystals in ,nature--,substitution of ,particles in ,crystals--,pseudomorphism--,crystalline ,form not dependent on ,chemical ,nature--,isomorphism--,dimorphism--,the ories of ,crystallogenic ,attraction--,influence of ,electricity and ,magnetism--,phenomena during ,crystallisation--,can a change of ,form take place in ,primitive ,atoms8--,illustrative ,example of ,crystallisation4 8,crystallisation is a peculiar and most admirable work of nature's geometry1 worthy of being studied by all the power of genius1 and the whole energy of the mind1 not on account of the delight which always attends the knowledge of wonders1 but because of its vast importance in revealing to us the secrets of nature2 for here she does1 as it were1 betray herself1 and1 laying aside all disguise1 permits us to behold1 not merely the results of her operations1 but the very processes themselves40--,such is the language of an ,italian philosopher1 ,gulielmini2 and it is the striking peculiarity of beholding the process of the formation of the regular geometric figures of crystals1 the gradual accretion of particle to particle1 which induces us to separate crystallization from mere molecular aggregation4 ,without doubt the formation of a crystal and the production of an amorphous block are due to powers which bear a close resemblance in many points2 but they present remarkable differences in others4 ,let us take some simple case in illustration4 ,in quiet water we have very finely divided matter suspended1 and matter in a state of solution4 ,the first is slowly precipitated1 and in process of time consolidates into a hard mass at the bottom1 presenting no particular character1 unless it has been placed in some peculiar physical conditions2 when1 as in nature1 we have a regular bedding which is intersected by lines of lamination or of cleavage1 which we are1 from experiment1 enabled to refer to the influence of current electricity4 ,the second--the matter in solution--is also slowly deposited2 but it is accumulated upon nuclei which possess some peculiar disposing powers1 and every particle is united by some particular face1 and an angular figure of the most perfect character results4 ,many pleasing experiments would appear to show that electricity has much to do in the process of crystallization2 but it is evident that it must be under some peculiarly modified conditions that this power is exerted1 if1 indeed1 it has any direct action4 ,the same substances always crystallize in the same forms1 unless the conditions of the crystallizing body are altered4 ,it has been supposed that each particle of a crystalline mass has certain points or poles which possess definite properties1 and that cohesion takes place only along lines which have some relation to the attracting or repelling powers of these poles4 ,we shall have1 eventually1 to consider results which appear to prove that magnetism is universal in its influence1 and that this polarity of the particles of matter may be referred to it4 ,be the cause of crystallisation what it may1 it presents to us in appearance a near approach in inorganic nature to some of the peculiar conditions of growth in the organised creation4 ,in one1 we have the gradual production of parts and the formation of members due to peculiar powers of assimilation1 each individual preserving all its distinguishing features2 and in the other1 we have a regular order of cohesion occurring under the influence of a power which draws like to like1 and arranges the whole into a form of beauty4 ,this appears to be the proper place for correcting an error too prevalent1 relative to the formation of crystals1 the development of cells1 and the yet more fatal falsehood of referring the great phenomena of ,life to any of the physical forces with which we are acquainted4 ,,the ,,crystal forms1 by the accretion of particle to particle1 along lines determined by some yet unknown power4 ,there is no change in the character of any particle--like coheres to like2 the first atom and the last of the series being identical in character4 ,,the ,,plant grows1 not by the gathering together of similar particles of matter1 but by the absorption of a compound particle--by that one which must be regarded as the primary nuclear atom or cell4 ,after this absorption--in virtue of a power which we call ,,life1 excited into action by ,,light--the compound particle is decomposed1 and one constituent is retained to effect the formation of a new cell1 whilst the other is liberated as an invisible air4 ,here we have a change of chemical constitution effected2 and this takes place through the whole period of vegetable growth1 from the development of the plumule up to the formation of the latest leaf upon the topmost branch of the most lordly tree4 ,life has been referred to electricity and to chemical power--as the effect of a known cause4 ,without doubt1 during the operations of life the whole of the physical powers are necessary to the production of all the phenomena of growth in the vegetable and the animal world4 ,but these powers are ever subsidiary to vital force1 and are like attendant spirits chained to do an enchanter's bidding4 ,life is a force beyond the reach of human search1 and he who fancies he has a hold upon the principle which produced biological phenomena1 has committed himself to as wild a pursuit as he who rashly endeavours to catch a morass-meteor4 ,subtile as are the forces of light1 heat1 and electricity--that of life1 vitality1 is infinitely more refined1 and it must for ever elude the search of the philosopher4 ,man is permitted to test and try all things which are created1 and to apply to useful ends the discoveries which he may make4 ,but man can never become a creator2 and he who would attempt to give sense to an inert mass of matter1 by electricity1 heat1 or light1 will prove himself as ignorant of nature's truth as is the senseless mass upon which he works4 8,so far shalt thou go1 and no further10 was said equally to the great tide-wave of human intellect1 as to the mighty surge of the earth-girdling ocean4 ,it must not be forgotten that a striking difference exists between the productions of the mineral and the other kingdoms of nature4 ,animals and vegetables arrive at maturity by successive developments1 and increase by the assimilation of substances1 having the power of producing the most important chemical changes upon such matter as comes within the range of their influence2 but minerals are equally perfect in the earliest stages of their formation1 and increase only1 as previously said1 by the accretion of particles without their undergoing any change4 ,the animal and vegetable tribes cease to continue the functions of life3 death ensues1 and a complete disorganisation takes place2 but this is not the case in the mineral world3 the crystal being the result of a constantly acting force is not necessarily liable to decomposition4 ,nevertheless1 we sometimes find in nature that crystals1 after arriving at what may be regarded as1 in some sort1 their maturity1 are1 owing to a change of the conditions under which they were formed1 gradually decomposed4 ,in our mines we discover skeletons of crystals1 and within the hollow shell thus formed1 other crystals of a different constitution and figure find nuclei1 and the conditions required for their development4 ,again1 to give a striking instance1 the felspar crystals of the granitic formations are liable to decomposition in a somewhat peculiar manner4 ,in decomposing1 these crystals leave moulds of their own peculiar forms1 and it not unfrequently happens1 in the stanniferous districts of ,cornwall1 that oxide of tin gradually fills these moulds1 and we procure this metallic mineral in the form of the earthy one4 ,then we have the curious instances of bodies crystallising in a false form under change of circumstances4 ,we find1 for example1 ,pseudomorphism1 7or false-form71 as this class of phenomena is named1 occurring by the removal of the constituent atoms of one crystal1 while another set--which naturally assumes a different form--takes their place1 yet still preserving the original shape4 ,it often happens that copper pyrites will1 in this manner1 exhibit the angles of an ordinary variety of crystallised carbonate of iron4 ,these curious changes may be familiarised by supposing a beautiful statue of gold1 from which some skilful mechanic removes particle by particle1 and so skilfully substitutes a grain of brass for every one of gold removed1 that the loss of the precious metal cannot be detected by any mere examination of its form4 ,crystalline form is not strictly dependent upon the chemical nature of the parts forming the crystal4 ,the same number of atoms1 arranged in the same way1 produce the same form4 ,substances much unlike each other will assume the same crystalline arrangement4 ,magnesia1 lime1 oxide of cadmium1 the protoxides of iron1 nickel1 and cobalt1 combined with the same acid1 present similarly formed bodies4 ,these ,isomorphic 7like-form7#cg peculiarities are exceedingly common1 and the discoverer of the phenomena1 ,mitscherlich1 announced the above law4 ,it cannot1 however1 be regarded as a philosophical expression of the fact1 and requires reconsideration--chemical elements of a dissimilar character may have the same law of aggregation1 and thus produce the same form1 without having any relation to the number of atoms4 ,we also find compounds which have two distinct systems of crystallisation4 ,this property1 ,dimorphism1 is very strikingly shown in carbonate of lime1 which occurs in rhombohedrons1 in calc spar1 and in rhombic prisms in arragonite4 ,the molecular arrangements here are not1 however1 of equal stability1 and one form is evidently forced upon the other1 and is abandoned by it on the slightest disturbance4 ,when a prism of arragonite is heated it breaks up into the rhombs of common calc spar1 at a temperature far below that at which the carbonate of lime is decomposed2 but no alteration of temperature can convert calc spar into arragonite4 ,crystals are found in the most microscopic character1 and of an exceedingly large size4 ,a crystal of quartz at ,milan is three feet and a quarter long1 and five feet and a half in circumference1 and its weight is #hgj pounds4 ,beryls have been found in ,new ,hampshire measuring four feet in length4#ch ,in the dark recesses of the earth1 where the influences which produce organisation and life cease to act1 a creative spirit still pursues its never-ending task of giving form to matter4 ,the science of crystallogeny1#ci embracing the theoretical and practical question of the causes producing these geometric forms1 has in various ways attempted to explain the laws according to which molecules arrange themselves on molecules in perfect order1 giving rise to a rigidly correct system of architecture4 ,but it cannot be said that any theory yet propounded is sufficiently exact to embrace the whole of the known phenomena1 and the questions1--,what is crystallogenic attraction1 and what is the physical nature of the ultimate particles of matter1--are still open for the inquiries of that genius which delights in wrestling with the secrets of nature4 ,the great ,epicurus speculated on the 8plastic nature0 of atoms1 and attributed to this nature the power they possess of arranging themselves into symmetric forms4 ,modern philosophers satisfy themselves with attraction1 and1 reasoning from analogy1 imagine that each atom has a polar system4 ,electricity1 and light1 and heat1 exert remarkable powers1 and accelerate or retard crystallisation according to the conditions under which these forces are brought to bear on the crystallising mass4 ,we have recently obtained evidence which appears to prove that some form of magnetism has an active influence in determining the natural forms of crystals1 and we discover that magnetism exerts a peculiar influence in relation to the optic axes of crystals1 which is not exerted in lines at right angles to these4 ,electricity appears to quicken the process of crystalline aggregation--to collect more readily together those atoms which seek to combine--to bring them all within the limits of that influence by which their symmetrical forms are determined2 and strong evidence is now afforded1 in support of the theory of magnetic polarity1 by the refined investigations of ,faraday and ,plcker1 which prove that magnetism has a directing influence upon crystalline bodies4#dj ,it has been found that crystals of sulphate of iron1 slowly forming from a solution which has been placed within the range of sufficiently powerful magnetic force1 dispose themselves along certain magnetic curves1 such as are formed around a magnet by steel filings2 whereas the crystals of the ,arbor ,dian1 or silver tree1 forming under the same circumstances1 take a position nearly at right angles to these curves4 ,certain groups of crystals have been found in nature1 which appear to show1 by their positions1 that terrestrial magnetism has been active in producing the phenomena they exhibit2 indeed1 nearly all our mineral formations indicate the influences of this1 or some similarly acting power4#da ,during rapid crystallisation1 some salts--as the sulphate of soda1 boracic acid1 and arsenious acid crystallising in muriatic acid--exhibit decided indications of electrical excitement2 light is given out in flashes4 ,we have evidence that crystals exhibit a tendency to move towards the light1 and that crystallisation takes place more readily1 and progresses with greater activity in the sunshine than in the shade4 ,professor ,plcker has recently ascertained that certain crystals--in particular the cyanite--8point very well to the north1 by the magnetic power of the earth only4 ,it is a true compass needle2 and1 more than that1 you may obtain its declination40 ,we must remember that this crystal1 the cyanite1 is a compound of silica and alumina only4 ,this is the amount of experimental evidence which science has afforded in explanation of the conditions under which nature pursues her wondrous work of crystal formation4 ,we see just sufficient of the operation to be convinced that the luminous star which shines in the brightness of ,heaven1 and the cavern-secreted gem1 are equally the result of forces which are known to us in only a few of their modifications4 ,every substance1 when placed under circumstances which allow of the free movement of its molecules1 has a tendency to crystallise4 ,all the metals may1 by slowly cooling from the melting state1 be exhibited with a crystalline structure4 ,of the metallic and earthy minerals1 nature furnishes us with an almost infinite variety of crystals1 and1 by a reduction of temperature1 yet more simple bodies assume the most symmetric forms4 ,water1 in the conditions of ice and snow1 is a familiar and beautiful example2 and1 by such extreme degrees of cold as are artificially produced1 many of the gases exhibit a tendency to a crystalline condition4 ,may not the solid elementary atoms be susceptible of change of form under different influences8 ,may not the different states under which the same bodies are found--as1 for example1 silica1 carbon1 and iron--be due entirely to a change in the form of the primitive atom8 ,admitting the probability of this1 we then easily see that the central molecule1 formed of an aggregation of such atoms1 uniting by particular faces1 would present a determinate form2 and that the resulting crystal1 a mass of such molecules1 cohering according to a given law1 at certain angles1 would present such geometric figures as we find in nature1 or produce in our laboratories1 when we avail ourselves of processes which nature has taught us4 ,if we take a particle of marble1 and place it in a large quantity of water acidulated with sulphuric acid1 it dissolves1 and a new compound results4 ,the marble disappears--the eye cannot detect it by form or colour3 the acid also has been disguised--the taste discovers nothing sour in the fluid4 ,we have1 in combination with the water1 the lime and sulphuric acid2 but that combination appears to the eye in no respect different from the water itself4 ,it is colourless and perfectly transparent1 although it holds a mass of solid matter which previously would not allow of the permeation of a ray of light4 ,let us expose this fluid to such circumstances that the water will slowly evaporate1 and we shall find forming in it1 after a time1 microscopic particles of solid1 light-refracting matter4 ,these particles gradually increase in size1 and we may watch their growth until eventually we have a symmetric figure1 beautifully shaped1 the primary form of which is a right rhomboidal prism4 ,thus in nature1 by the action1 in all probability1 of vegetable matter on the sulphates held in solution by the water of the great rivers and the ocean--aided by our oxidizing atmosphere--sulphuric acid is produced to do its work upon the limestone formations1 and from this combination would result the well-known gypsum1 or plaster of ,paris1 which ordinarily exists as an amorphous mass1 but is often found in a crystalline form4#db ,this is a very perfect illustration of the wonderful process we have been considering1 and in which1 simple though it appears to be1 we have set to work a large proportion of the known physical elements of the universe4 ,by studying aright the result which we have it in our power to obtain in a watch-glass1 we may advance our knowledge of gigantic phenomena1 which are now progressing at the bottom of the ocean1 or of the wondrous agencies which are in operation1 producing light-refracting gems within the secret recesses of the rocky crust of our globe4 ,the force of crystallisation is a subject worthy of much consideration4 ,if we examine our slate rocks1 through which little veins filled with quartz crystals are spread1 we shall see that the mechanical force exerted during the production of these crystals has been capable of rending those rocks in every direction4 ,those fissures formed by the first system of crystalline veins1 in order of time1 are filled in by another set of crystalline bodies1 which equally exert their mechanical power1 and thus produce those curious intersections and dislocations which were long a puzzle to the geologist4 ,the simplest power1 slowly and constantly acting through a long period of time1 may become sufficient1 eventually1 to rend the ,andes from base to summit1 or to lift a new continent above the waters of the ocean4 ,,footnotes3 #cg 8,gay ,lussac first made the remark1 that a crystal of potash alum1 transferred to a solution of ammonia alum1 continued to increase without its form being modified1 and might thus be covered with alternate layers of the two alums1 preserving its regularity and proper crystalline figure4 ,m4 ,beudant afterwards observed that other bodies1 such as the sulphates of iron and copper1 might present themselves in crystals of the same form and angles1 although the form was not a simple one1 like that of alum4 ,but ,m4 ,mitscherlich first recognised this correspondence in a sufficient number of cases to prove that it was a general consequence of similarity of composition in different bodies40--,graham's ,elements of ,chemistry 7#ahdb71 p4 #acf4 ,the following remarks are from a paper by ,dr4 ,hermann ,kopp1 ,on the ,atomic ,volume and ,crystalline ,condition of ,bodies1 c41 published in the ,philosophical ,magazine for #ahda3--8,the doctrine of isomorphism shows us that there are many bodies which possess an analogous constitution1 and the same crystalline form4 ,our idea of the volume 7or1 in other words1 of the crystalline form7 of these bodies must therefore be the same4 ,from this it follows that their specific weight is connected with mass contained in the same volume4 ,from these considerations the following law may be deduced3 ,the specific weight of isomorphous bodies is proportional to their atomic weight1 or isomorphous bodies possess the same atomic volume40--page #bee4 ,a translation appears in the ,cavendish ,society1 from ,dr4 ,otto's ,chemistry1 ,on ,isomorphism1 which may be advantageously consulted4 ,see also a paper by ,m4 ,rose1 translated from the ,proceedings of the ,royal ,berlin ,academy for the ,chemical ,gazette1 ,oct4 #ahdh1 entitled1 ,on the ,isomeric ,conditions of the ,peroxide of ,tin4 #ch ,a ,system of ,mineralogy1 comprising the most recent discoveries1 by ,james ,d4 ,dana1 ,a4,m41 ,new ,york1 #ahdd4 #ci ,crystallogeny1 or the formation of crystals1 is the term employed by ,dana1 in his admirable work quoted above3 whose remarks on ,theoretical ,crystallogeny1 p4 #ga1 are well worthy of all attention4 #dj ,on the ,magnetic ,relations of the ,positive and ,negative ,optic ,axes of ,crystals1 by ,professor ,plcker1 of ,bonn4--,philosophical ,magazine1 ,no4 #bca 7#crd ,series71 p4 #dej4 ,experimental ,researches on ,electricity2 ,on the ,crystalline ,polarity of ,bismuth and other bodies1 and on its ,relation to the ,magnetic form of ,force3 by ,michael ,faraday1 ,esq41 ,f4,r4,s4--,transactions of the ,royal ,society for #ahdh4 #da ,in the ,memoirs of the ,geological ,survey of the ,united ,kingdom1 and of the ,museum of ,economic ,geology1 vol4 i4 #ahdf1 will be found a paper1 by the author of this volume1 ,on the ,influences of ,magnetism on ,crystallisation1 and other ,conditions of ,matter1 in which the subject is examined with much care4 ,see also ,magntisme polaire d'une montagne de ,chlorite schisteuse et de ,serpentine3 ,annales de ,chimie1 vol4 xxv4 p4 #cbg2 ,influence du ,magntisme sur les actions chimiques1 by l',abb ,rendus2 and also a notice of the experiments of ,ritter and ,hansteen1 8,analyses par ,m4 rsted20 also ,effets du ,magntisme terrestre sur la prcipitation de l',argent1 observs par ,m4 ,muschman3 ,annales de ,chimie1 vol4 xxxviii4 p4 #aif-bja4 #db ,the transparent varieties of sulphate of lime are distinguished by the name ,selenite2 and the fine massive varieties are called ,alabaster4 ,gypsum forms very extensive beds in secondary countries1 and is found in tertiary deposits2 occasionally1 in primitive rocks2 it is also a product of volcanoes4 ,the finest foreign specimens are found in the salt mines of ,bex1 in ,switzerland2 at ,hall1 in the ,tyrol2 in the sulphur-mines of ,sicily2 and in the gypsum formation near ,ocana1 in ,spain4 ,in ,england1 the clay of ,shotover ,hill1 near ,oxford1 yields the largest crystals4--,see ,dana's ,mineralogy1 second edition1 p4 #bda4 ,,chapter ,,vi4 ,,heat--,,solar ,,and ,,terrestrial4 ,solar and ,terrestrial ,heat--,position of the ,earth in the ,solar ,system--,heat and ,light associated in the ,sunbeam--,transparency of ,bodies to ,heat--,heating ,powers of the ,coloured ,rays of the ,spectrum--,undulatory ,theory--,conducting ,property of the ,earth's ,crust--,convection--,radiation--,action of the ,atmosphere on ,heat ,rays--,peculiar ,heat ,rays--,absorption and ,radiation of ,heat by dissimilar ,bodies--,changes in the ,constitution of ,solar ,beam--,differences between ,transmitted and ,reflected ,solar ,heat--,phenomena of ,dew--,action of ,solar ,heat on the ,ocean--,circulation of ,heat by the ,atmosphere and the ,ocean--,heat of the ,earth--,mean ,temperature--,central ,heat--,constant ,radiation of ,heat ,rays from all ,bodies--,thermography--,action of ,heat on ,molecular ,arrangements--,sources of ,terrestrial ,heat--,latent ,heat of ,bodies--,animal ,heat--,eremacausis--,spheroidal ,state ,cold--,condensation--,freezing--,theori es of ,heat--,natural ,phenomena--and ,philosophical ,conclusion4 ,we receive heat from the sun1 associated with light2 and we have the power of developing this important principle by physical1 mechanical1 and chemical excitation1 from every kind of matter4 ,our convictions are1 that the calorific element1 whether derived from a solar or a terrestrial source1 presents no essential difference in its physical characters2 but as there are some remarkable peculiarities in the phenomena1 as they arise from either one or the other source1 it will assist our comprehension of this great principle1 if we consider it under the two heads4 ,untutored man finds health and gladness in the warmth and light of the sun2 he rears a rugged altar1 and bows his soul in prayer1 to the principle of fire1 which in his ignorance he regards as the giver and the supporter of life4 ,the philosopher finds life and organization dependent upon the powers combined in the sunbeam2 and1 examining the phenomena of this wonderful band of forces1 he is compelled to acknowledge that the flame upon the altar--on the ,persian hills1--was indeed a dim shadow of the infinite wisdom which abides behind the veil4 ,the present condition of our earth is directly dependent upon the amount of heat we receive from the sun4 ,it has frequently been said1 that if it were possible to move this planet so much nearer that orb that the quantity of heat would be increased1 the circumstances of life would necessarily be so far changed1 that all the present races of animals must perish2 and that the same result would happen from any alteration which threw us yet further from our central luminary1 when1 owing to the extremity of cold and the wretchedness of gloom1 all living creatures would equally fail to support their organization4 ,to move the earth nearer to1 or more distant from the sun1 is an impossibility2 but it has been argued that those planets which are near to the sun must possess a temperature which would melt our solid rocks1 and vaporize the ocean1--while ,uranus and ,neptune must1 from their distance from the source of heat1 have so small an amount1 that water must become solid as the rock1 and such an atmosphere as that of the earth exist as a dense liquid4 ,it will be shown that according to the physical condition of the material substances1 so are their powers regulated of absorbing and retaining the heat which falls as a radiant power upon their surfaces4 ,heat rays1 in passing through the attenuated medium of planetary space1 lose none of their power--this we know from the fact that even the less dense upper region of the earth's atmosphere takes from the solar rays but an exceedingly small quantity of heat4 ,therefore1 whether a solar heat ray traverses through one million1 or one hundred million miles of space1 it still retains its power equally of imparting warmth to the solid matter by which it is intercepted4 ,there is no law of variation as the inverse square of the distance of those radiating powers4 ,consequently1 there is no reason why the physical conditions1 alike of the nearest and the most remote planetary bodies1 should not be so adjusted that they all enjoy that life promoting temperature which belongs to the earth4 ,all the objects around us are adapted to the circumstances of the earth's position in relation to the sun1 to which we are bound by the principle of gravitation2 opposed to that centrifugal force which tends constantly to drive the moving planetary mass off from the centre of power4 ,the balance maintains its perfect equilibrium1 although we have one power constantly drawing the earth towards the sun1 and the other as constantly exerting itself to move it off into space at a tangent to the orbit in which the planet moves4 ,in our examination it will be found that one common system of harmony runs through all the cosmical phenomena1 by which everything is produced that is so beautiful and joyous in this world4 ,heat1 and the other elementary radiant principles1 are often combined as the common cause of effects evident to our senses4 ,the warmth of the solar rays1 and their luminous influence1 are not1 however1 commonly associated in the mind as the results of a single cause4 ,it is only when we come to examine the physical phenomena connected with these radiations that we discover the complexity of the inquiry4 ,yet it is out of these very subtle researches that we draw the most refined truths4 ,the high inferences to which the analysis of the subtile agencies of creation leads us1 render science1 pursued in the spirit of truth1 a great system of religious instruction4 ,although we do not fear that heat and light can be confounded in the mind1 so different are their phenomena1--we have heat rays1 as from dark hot iron1 which give no light1 while in the full flood of the lunar rays the heat is scarcely appreciable by the most delicate instruments2--yet it is important to show how far these two principles have--been separated from each other4 ,transparent bodies have varied powers of calorific transparency1 or transcalescence3 some obstructing the heat radiated from bodies of the highest temperatures almost entirely even in the thinnest layers2 whilst others will allow the warmth of the hand to pass through a thickness of several inches4 ,liquid chloride of sulphur1 which is of a deep red colour1 will allow #fc out of #ajj rays of heat to pass1 and a solution of carmine in ammonia1 or glass stained with oxides of gold1 or copper1 rather a greater number2 yet these transparent media obstruct a large quantity of light4 ,colourless media obstructing scarcely any light1 will1 on the contrary1 prevent the passage of calorific rays4 ,out of every hundred rays1 oil of turpentine will only transmit #ca1 sulphuric ether #ba1 sulphuric acid #ag1 and distilled water only #aa4 ,pure flint glass1 however1 is permeated by #fg per cent4 of the thermic rays1 and crown glass by #di per cent4 ,the body possessing the most perfect transparency to the rays of heat is diaphanous salt-rock1 which transmits #ib1 while alum1 equally translucent1 admits the passage of only #ab per cent4#dc ,black mica1 obsidian1 and black glass1 are nearly opaque to light1 but they allow #ij per cent4 of radiant heat to pass through them2 whereas a pale green glass1 coloured by oxide of copper1#dd covered with a layer of water1 or a very thin plate of alum1 will1 although perfectly transparent to light1 almost entirely obstruct the permeation of heat rays4 ,we thus arrive at the fact that heat and light may be separated from each other2 and if we examine the solar beam by that analysis which the prism affords1 we shall find that there is no correspondence between intense light and ardent heat4 ,by careful observation1 it has been proved1 when we have a temperature of #fb ,f4 in the yellow ray1 which ray has the greatest illuminating power2 that below the red ray1 out of the point of visible light1 the temperature is found to be #gi1 while at the other end of the spectrum1 in the blue ray1 it is #ef1 and at the end of the violet ray no thermic action can be detected4#de ,from the circumstance1 that as we1 by artificial means1 raise the temperature of any body1 and produce intense heat1 so after a certain point of thermic elevation has been obtained1 we occasion a manifestation of light4#df ,it has been concluded1 somewhat hastily1 that heat and light differ from each other only in the rapidity of the undulations of an hypothetical ether4 ,it must be admitted that the mathematical demonstrations of many of the phenomena of calorific and luminous power are sufficiently striking to convince us that a wave-movement is common to both heat and light4 ,the undulatory theory1 however1 requires the admission of so many premises of which we have no proof2 its postulates are1 indeed1 in many cases so gratuitous1 that notwithstanding the array of talent which stands forward in its support1 we must not allow ourselves to be deceived by the deductions of its advocates1 or dazzled by the brilliancy of their displays of learning4 ,radiant heat appears to move in waves2 but that calorific effects in material bodies are established by any system of undulation1 is a deduction without a proof2 and the thermic phenomena of matter are as easily explained by the hypothesis of a diffusive subtile fluid4 ,we have not1 however1 to prove the correctness of either of the opposing views2 indeed1 it is acknowledged that many phenomena require for their explanation conditions which are not indicated by either theory4 ,the earth receives its heat from the sun2 a portion of it is conducted from particle to particle into the interior of the rocky crust4 ,another portion produces warmth in the atmosphere around us1 by convection1 or the circulation of particles2 those warmed by contact with the surface becoming lighter1 and ascending to give place to the colder and heavier ones4 ,a third portion is radiated off into space1 according to laws which have not been sufficiently investigated1 but which are dependent upon the colour1 chemical composition1 and mechanical structure of the surface4 ,it cannot but be instructive to contemplate the indications which we have of the dependence of all that is beautiful on earth1 on the heat and light radiations which we receive from the sun4 ,let us endeavour to realise some of the effects which arise from even the temporary deprivation of solar heat4 ,it is winter1 the vegetable world appears chilled to its centre4 ,the trees1 except a few of the hardy evergreens1 are bare of leaves1 and stretching forth their branches into the cold air1 they realise the condition of vegetable skeletons4 ,the lowly plants of the hedge-row1 and the grasses of the field1 show that their vital power is subdued to that minimum degree of action which is but a few slight removes from death4 ,the life of the running stream is suspended1 it is cased in the 8thick-ribbed ice10 and the waters beneath no longer send forth their joyous music to the genial breeze4 ,even within the temperate limits of our own land1 the aspect of winter convinces the ordinary observer1 that the loss of heat has been followed by diminished activity in the powers of life2 and the philosopher discovers that the lessened energies of solar light1 and the weaker action of the radiant heat1 have aided in producing that repose which is a little more than sleep--a little less than death4 ,it is night1 and winter3 the earth is parting with its heat1--with the absence of light1 there is a still greater loss of vigour1 a yet further diminution of the powers of life4 ,even the animal races1 sustained by vital influences of a more exalted kind1 sink under the temporary deprivation of the solar rays to a monotonous1 a melancholy repose4 ,all animals undergo different degrees of hybernation1 and each in his winter retreat supports vitality by preying upon himself4 ,the world is hung in mourning black2 there is no play of colours to harmonize the human spirit by sending their ethereal pulsations to the human eye1 and it is only the consciousness that when the night is at the darkest1 the day is nearest1 that even man's soul is sustained against the depressing influences of the absence of the sun4 ,the conditions which we must observe at our own doors cannot fail to convey as a conviction to the least imaginative mind1 that a slightly prolonged continuance of darkness1 with its consequent increase of coldness1 would be fatal to the existence of the organic world4 ,the sun has entered ,aries3 it is spring4 ,the length of the day and night are equal1 the powers of light and darkness are now exactly balanced against each other1 and light1 like the ,archangel1 triumphs over the sombre spirit4 ,the organic world awakes4 ,chemical action commences in the seed1 the vital spark is kindled in the embryo1 and under the impulsive force of some solar radiations the plant struggles into light and life4 ,the same invigorating force impels the circulation of the sap through the capillary tubes of the forest tree1 until the topmost branch trembles with the new flow of life4 ,the buds burst forth into leaf1 and a fresh and lively covering spreads over those branches which1 in their nakedness1 could scarcely be distinguished from the dead4 ,the animal races are no less sensible of the new influence which is diffused around4 ,the birds float joyously upon the breeze1 and give to heaven their trilling songs of praise4 ,the beasts come forth from the clefts of the rocks and the tangled shelters of the forests1 and gambol in the full luxury of their renewed vigour4 ,man1 even man1 the inhabitant of cities1 trained and tempered to an artificial state1 awakes of a spring morning with a fuller consciousness of mind1 and a deeper and more pleased sense of his intelligence1 than when the fogs and gloom of winter hung like the charmed robe upon the limbs of the giant4 ,now1 the dormant poetry of man seeks expression4 ,as the morning sun is said to have awakened the musical undulations of the ,memnonian statue1 so the sun of the vernal morning produces in the mind of the most earthly1 faint pulsations of that heaven-born music1 which neither sin nor sorrow can entirely destroy4 ,the psychologist1 in studying the peculiar phenomena of the human mind1 must associate himself with the natural philosopher1 and learn to appreciate the influence of physical causes in determining effects which our elder philosophers and the poets of every age have attributed to spiritual agencies4 ,summer1 with its increased heat and light1 reigns over the land4 ,the work of life is now at its maximum1 and every energy is quickened throughout the organic creation4 ,the laws of nature are arranged on the principle of antagonistic forces1 the constant struggle to maintain them in equilibrium constituting the sensible phenomena of existence4 ,heat and light1 with chemical power and electricity1 have been quickening the unknown principle of life1 until it has become exhausted in the production of new parts--in the strange phenomenon of growth--the formation of organized matter from the inorganic stores of creation4 ,the autumn1 with its tempered sunlight1 comes1 but in the solar radiance we discover new powers1 and under the influence of these the flower and the fruit have birth4 ,the store of a new life is centered in the seed1 and though the leaf falls1 and the flower fades1 a new set of organisms are produced1 by which the continuance of the species is secured4 ,let any man examine himself as the seasons change1 and he will soon be convinced that every alternation of light and darkness1 of heat and its absence1 produces new sets of influences equally on the mind and on the body1 showing the entire dependence of the animal and vegetable kingdoms upon those causes which appear to flow from the centre of our planetary system4 ,the phenomena which connect themselves with the changes of the seasons cannot fail to convince the most superficial thinker that there is an intimate connection between the sun and the earth which deserves our close attention4 ,indeed1 if we examine the most ancient of histories1 we find one great fact at the base of all their philosophies4 ,moses connects darkness with a void and formless earth1 and light with the creation of harmony and life4 ,menis sings of a fearful world by 8many formed darkness encircled10 and links the idea of a 8life-breathing divinity0 with the awakening of light upon created things4 ,the ,egyptian ,isis1 the ,grecian ,apollo1 who1 ,the ,lord of boundless light ,ascending calm o'er the empyrean sails1 ,and with ten-thousand beams his awful beauty veils1 the fire-worshipper of the ,persian hills and the sun-god of the ,peruvian mountains1 exhibit1 through time and space1 the full consciousness of man to the influences of solar light and heat upon the organic creations of which he is himself the chief exemplar4 ,the investigations of modern philosophers have extended these influences to the inorganic masses which constitute the ,planet ,,earth3--and we now know that the physical forces1 ever active in determining the chemical condition and the electrical relations of matter1 are directly influenced by the solar radiations4 ,few things within the range of our inquiry are more striking than the phenomena of calorific radiation and absorption4 ,they display so perfectly the most refined system of order1 and exhibit so strikingly the admirable adaptation of every formation to its particular conditions1 and for its part in the great economy of being1 that they claim most strongly the study of all who would seek to discover a poetry in the inferences of science4 ,owing to the nature of our atmosphere1 we are protected from the influence of the full flood of solar heat4 ,the absorption of caloric by the air has been calculated at about one-fifth of the whole in passing through a column of #f1jjj feet4 ,this estimate is1 of course1 made near the earth's surface2 but we are enabled1 knowing the increasing rarity of the upper regions of our gaseous envelope in which the absorption is constantly diminishing1 to prove1 that about one-third of the solar heat is lost by vertical transmission through the whole extent of our atmosphere4#dg ,experience has proved that the conditions of the sun's rays are not always the same2 and there are few persons who have not observed that a more than usual scorching influence prevails under some atmospheric circumstances4 ,this is also evidenced in the effects produced on the foliage of trees1 which1 though often attributed to electricity1 is evidently due to heat4 ,an examination of the solar radiations1 as exhibited in the prismatic spectrum1 has proved the existence of a class of heat rays1 which manifest themselves by a very peculiar deoxidizing power quite independent of their caloric properties1 to which the name of parathermic rays has been given4#dh ,we are protected from the severe effects of these rays by the ordinary state of the medium through which the solar heat passes4 ,our atmosphere is a mixture of gases and aqueous vapour2 and it has been found1 as already stated1 that even a thin film of water1 however transparent1 prevents the passage of many calorific radiations1 and the rays retarded are1 for the most part1 of that class which have this peculiar scorching power4 ,the air is1 in this way1 the great equaliser of the solar heat1 rendering the earth agreeable to all animals1 who1 but for this peculiar absorbent medium1 would have to endure1 even in our temperate clime1 the burning rays of a more than ,african sun4 ,the surface of the earth during the sunshine--and1 though in a less degree1 even when the sun is obscured by clouds--is constantly receiving heat2 but the rate of its absorption varies4 ,benjamin ,franklin showed1 by a set of simple but most conclusive experiments1 that a piece of black cloth was warmed much sooner than cloth of a lighter colour2#di and we know1 from observations of a similar class1 that the bare brown soil receives heat more readily than the bright green grassy carpet of the earth4 ,consequently1 during the winter season1 relatively to the quantity poured from its source1 more heat penetrates the uncovered soil1 than during the spring or summer4 ,there is a constant tendency to an equilibrium2 and1 during the night1 the surface is robbed of more heat1 by the colder air1 than by day2 as1 when the earth is not receiving heat1 it is constantly radiating it back into space4 ,even in these processes of convection and radiation1 a similar law prevails to that which is discovered in examining into the rate of calorific absorption4 ,every tree spreading its green leaves to the sunshine1 or exposing its brown branches to the air--every flower which lends its beauty to the earth--possesses different absorbing and radiating powers4 ,the chalice-like cup of the pure white lily floating on the lake--the variegated tulip--the brilliant anemony--the delicate rose--and the intensely coloured peony or dahlia--have each powers peculiar to themselves for drinking in the warming life-stream of the sun1 and for radiating it back again to the thirsting atmosphere4 ,these are no conceits of a scientific dreamer2 they are the truths of direct induction2 and1 by experiments of a simple character1 they may be put to a searching test4#ej ,a thermometric examination of the various coloured flowers1 by enclosing a delicate thermometer amongst their leaves1 will readily establish the correctness of the one2 and by a discovery of recent date1 connected with calorific radiation1 which must be particularly described presently1 we can1 with equal ease and certainty1 test the truth of the other2#ea the absorption and radiation of heat being directly regulated by the colours of the surfaces upon which the sun rays fall4 ,it follows1 as a natural consequence of the position of the sun1 as it regards any particular spot on the earth at a given time1 that the amount of heat is constantly varying during the year4 ,this variation regulates the seasons4 ,when it is remembered that the earth is1 in the winter1 nearly three millions of miles nearer the sun than in the summer1 some explanation is required to account for our suffering more cold when nearer the source of heat1 than when at the remotest distance4 ,the earth in her path around the sun describes an ellipse1 the sun's place being one of its foci4 ,in obedience to the law1 already described1 of the conservation of the axis of rotation1 the axis of the earth constantly points towards the star in the constellation of the ,little ,bear4 ,recollecting this1 and also the two facts1 that a dense solid body absorbs heat more readily than a fluid one1 and that radiation from the surface is constantly going on when absorption is not taking place1 let us follow the earth in her orbit4 ,it is the time of the vernal equinox--we have equal day and night--therefore the periods of absorption and radiation of heat are alike4 ,but at this time of the year the southern hemisphere is opposite to the sun1 consequently the degree of absorption by the wide-spread oceans small4 ,it is the summer solstice--we have sixteen hours of daylight1 when the absorption of heat is going on--and but eight hours of night1 during which heat is passing off4 ,the northern hemisphere is now presented to the sun1 and as here we have the largest portion of dry land1 the powers of absorption are at their maximum4 ,the autumnal equinox has arrived1 with its equal day and night1 as in the spring1 but now the whole northern hemisphere is opposite the sun2 hence1 according to the laws already explained1 we see the causes of the increased heat of the autumnal season4 ,the winter solstice has come1 with its long night and shortened day4 ,the time during which radiation is going on is nearly twice that in which absorption takes place1 and the earth is in her worst position for receiving heat1 as that half which has the largest surface of water is towards the sun4 ,these are the causes which lead to the variations of the seasons1 and through these we learn why we are colder when near the sun than when at a considerably greater distance4 ,an analysis of the spectrum shows us that there are some changes regularly taking place in the state of the solar beam1 which cannot be referred to the mere alteration of position4 ,it may be inferred1 from facts by long-continued observations1 that the three classes of phenomena--light1 heat1 and chemical power1 distinguished by the term ,actinism--which we detect in the sun's rays1 are constantly changing their relative proportions4 ,in spring1 the chemical agency prevails2 in summer1 the luminous principle is the most powerful2 and in the autumn1 the calorific forces are in a state of the greatest activity4#eb ,the importance of these variations1 to the great economy of vegetable life1 will be shown when we come to examine the phenomena connected with organisation4 ,a remarkable change takes place in the character of heat in being reflected from material substances4 ,in nature we often see this fact curiously illustrated4 ,snow which lies near the trunks of trees or wooden poles melts much quicker than that which is at a distance from them1 the sun shining equally on both--the liquefaction commencing on the side facing the sun1 and gradually extending4 ,we see1 therefore1 that the direct rays of solar heat produce less effect upon the snow than those which are radiated from coloured surfaces4 ,by numerous experiments1 it has been shown that these secondary radiations are more abundantly absorbed by snow or white bodies than the direct solar rays themselves4 ,here is one of the many very curious evidences1 which science lays open to us1 of the intimate connection between the most ethereal and the grosser forms of matter4 ,heat1 by touching the earth1 becomes more earth-like4 ,the subtile principle which1 like the spirit of superstition1 has the power of passing1 unfelt1 through the crystal mass1 is robbed of its might by embracing the things of earth2 and although it still retains the evidences of its refined origin1 its movements are shackled as by a clog of clay1 and its wings are heavy with the dust of this rolling ball4 ,it has1 however1 acquired new properties1 which fit it for the requirements of creation1 and by which its great tasks are facilitated4 ,matter and heat unite in a common bond1 and1 harmoniously pursuing the necessities of some universal law1 the result is the extension of beautiful forms in every kingdom of nature4 ,an easy experiment pleasingly illustrates this remarkable change4 ,if a blackened card is placed upon snow or ice in the sunshine1 the frozen mass underneath it will be gradually thawed1 and the card sink into it1 while that by which it is surrounded1 although exposed to the full power of solar heat1 is but little disturbed4 ,if1 however1 we reflect the sun's rays from a metal surface1 an exactly contrary result takes place2 the uncovered parts are the first to melt1 and the blackened card stands high above the surrounding portion4 ,the evidences of science all indicate the sun as the source1 not only of that heat which we receive directly through our atmosphere1 but even of that which has been stored by our planet1 and which we can1 by several methods1 develope4 ,we have not to inquire if the earth was ever an intensely heated sphere2--this concerns not our question2 as we should1 even were this admitted1 still have to speculate on the origin--the primitive source of this caloric4 ,before1 however1 we proceed to the examination of the phenomena of terrestrial heat1 a few of the great results of the laws of radiation and convection claim our attention4 ,nearly all the heat which the sun pours upon the ocean is employed in converting its water into vapour at the very surface1 or is radiated back from it1 to perform the important office of producing those disturbing influences in the atmosphere1 which are essential to the preservation of the healthful condition of the great arial envelope in which we live4 ,currents of air are generally due to the unequal degrees in which the atmosphere is warmed4 ,heat1 by expanding1 increases the elasticity1 and lessens the density1 of a given mass4 ,consequently1 the air heated by the high temperature of the tropics1 ascends charged with aqueous vapours1 whilst the colder air of the temperate and the frigid zones flows towards the equator to supply its place4 ,these great currents of the atmosphere are1 independent of the minor disturbances produced by local causes1 in constant flow1 and by them a uniformity of temperature is produced1 which could not in any other way be accomplished4 ,by these currents1 too1 the equalisation of the constituents of the 8breath of life0 is effected1 and the purer oxygen of the 8land of the sunny south0 is diffused in healthful gales over the colder climes of the north4 ,the waters1 too1 evaporated from the great central ,atlantic ,ocean1 or the far ,pacific1 are thus carried over the wide-spread continents1 and poured in fertilising showers upon distant lands4 ,how magnificent are the operations of nature6 ,the air is not much warmed by the radiations of caloric passing from the sun to the earth2 but the surface soil is heated by its power of absorbing these rays4 ,the temperature of the air next the earth is raised1 and we thus have the circulation of those beneficial currents which are so remarkably regular in the ,trade ,winds4 ,the air heated within the tropics would ascend directly to the poles1 were the earth at rest1 but being in motion1 those great arial currents--the ,trade ,winds--are produced1 and the periodical monsoons are due to the same cause4 ,a similar circulation1 quite independent of the ordinary tidal movement1 takes place also in the earth-girdling ocean4 ,the water1 warmed1 by convection1 from the hot surface of the tropical lands1 sets across the ,atlantic from the ,gulf of ,mexico2 and being under the influence of the two forces--gravity and motion--it illustrates the parallelogram of forces1 and flowing along the diagonal1 reaches our own shores3 the genial influences of the gulf stream produce that tempered climate which distinguishes our insular home4 ,here we have two immense influences produced by one agency1 rendering those parts of the earth habitable and fertile1 which but for these great results would sorrow in the cheerless aspect of an eternal winter4 ,the beautiful phenomenon of the formation of dew is also distinctly connected with the peculiar properties which we have been studying4 ,when from the bright blue vault of heaven1 the sparkling constellations shower their mild light over the earth1 the flowers of the garden and the leaves of the forest become moist with a fluid of the most translucid nature4 ,well might the ancients imagine that the dews were actually shed from the stars2 and the alchemists and physicians of the middle ages conceive that this pure distillation of the night possessed subtile and penetrating powers beyond most other things2 and the ladies of those olden times endeavour to preserve their charms in the perfection of their youthful beauty through the influences of washes procured from so pure a source4#ec ,science has removed the veil of mystery with which superstition had invested the formation of dew2 and1 in showing to us that it is a condensation of vapour upon bodies according to a fixed law of radiation1 it has also developed so many remarkable facts connected with the characters of material creations1 that a much higher order of poetry is opened to the mind than that which1 though beautiful1 sprang merely from the imagination4 ,upon the radiation of heat depends the formation of dew1 and bodies must become colder than the atmosphere before it will be deposited upon them4 ,at whatever temperature the air may be1 it is charged to saturation with watery vapour1 the quantity varying uniformly with the temperature4 ,supposing the temperature of the air to be #gj ,f41 and that a bottle of water at #fj is placed in it1 the air around the bottle will be cooled1 and will deposit on the glass exactly that quantity of moisture which is due to the difference between the temperature of the two bodies4 ,different substances1 independent of colour1 have the property of parting with heat from their surfaces at different rates4 ,rough and porous surfaces radiate heat more rapidly than smooth ones1 and are consequently reduced in temperature2 and1 if exposed1 are covered with dew sooner than such as are smooth and dense4 ,the grass parterre glistens with dew1 whilst the hard and stony walk is unmoistened4#ed ,colourless glass is very readily suffused with dampness1 but polished metals are not so1 even when dews are heavily condensed on other bodies4 ,to comprehend fully the phenomena of the formation of dew1 we must remember that the entire surface of the earth is constantly radiating heat into space2 and that1 as by night no absorption is taking place1 it naturally cools4#ee ,as the substances spread over the earth become colder than the air1 they acquire the power of condensing the vapour with which the atmosphere is always charged4 ,the bodies which cover this globe are very differently constituted2 they possess dissimilar radiating powers1 and consequently present1 when examined by delicate thermometers1 varying degrees of temperature4 ,by the researches of ,dr4 ,wells1#ef which may be adduced as an example of the best class of inductive experiments1 we learn that the following differences in sensible heat were observed at seven o'clock in the evening3-- ,the air four feet above the grass #fj-c_/d ,wool on a raised board #ed-a_/b ,swandown on ditto #ec ,the surface of the raised board #eg ,grass plat #ea ,dew is most abundantly deposited on clear1 calm nights1 during which the radiation from the surface of the earth is uninterrupted4 ,the increased cold of such nights over those obscured by clouds is well known4 ,the clouds1 it has been proved1 act in the same way as the screens used by gardeners to protect their young plants from the frosts of the early spring1 which obstruct the radiation1 and1 in all probability1 reflect a small quantity of heat back to the earth4 ,it is not improbable that the observed increase in grass crops1 when they have been strewn with branches of trees or any slight shades1 may be due to a similar cause4#eg ,there are many remarkable results dependent entirely on the colours of bodies1 which are not explicable upon the idea of difference in mechanical arrangement4 ,we know that different colours are regulated by the powers which structures have of absorbing and reflecting light2 consequently a blue surface must have a different order of molecular arrangement from a red one4 ,but there are some physical peculiarities which also influence heat radiation1 quite independently of this surface condition4 ,if we take pieces of red1 black1 green1 and yellow glass1 and expose them when the dew is condensing1 we shall find that moisture will show itself first on the yellow1 then on the green glass1 and last of all upon the black or red glasses4 ,the same thing takes place if we expose coloured fluids in white glass bottles or troughs1 in which case the surfaces are all alike4 ,if against a sheet of glass1 upon which moisture has been slightly frozen1 we place glasses similarly coloured to those already described1 it will be found that the earliest heat-rays will so warm the red and the black glasses1 that the ice will be melted opposite to them1 long before any change will be seen upon the frozen film covered by the other colours4 ,the order in which heat permeates coloured media1 it has already been shown1 very nearly agrees with their powers of radiation4 ,these most curious results have engaged the attention of ,melloni1 to whose investigations we owe so much2 and from the peculiar order of radiations1 which present phenomena of an analogous character to those of the coloured rays of light1 obtained by him from dissimilarly coloured bodies1 he has been led to imagine the existence of a 8heat-colouration40 ,that is1 the heat-rays are supposed to possess properties like luminous colour although invisible2 and1 consequently1 that a blue surface has a strong affinity for the blue heat-rays1 a red surface for the red ones1 and so on through the scale4 ,the ingenuity of this hypothesis has procured it much attention2 but now1 when the ,newtonian hypothesis of the refrangibility of light is nearly overturned1 we must not1 upon mere analogy1 rush to the conclusion that the rays of heat have different orders of refrangibility1 which ,melloni's hypothesis requires4#eh ,can anything be more calculated to impress the mind with the consciousness of the high perfection of natural phenomena1 than the fact1 that the colour of a body should powerfully influence the transmission of a principle which is diffused through all nature1 and also determine the rate with which it is to pass off from its surface4 ,some recent experiments have brought us acquainted with other facts connected with these heat-radiations1 and the power of heat1 as influenced by the calorific rays1 to produce molecular changes in bodies1 which bear most importantly on our subject4 ,if we throw upon a plate of polished metal a prismatic spectrum 7deprived1 as nearly as possible1 of its chemical power1 by being passed through a deep yellow solution--which possesses this property in a very remarkable manner1 as will be explained when we come to the examination of the chemical action of the sun's rays7--it will be found1 if we afterwards expose the plate to the action of vapour1 very slowly raised from mercury1 that the space occupied by the red rays1 and those which lie without the spectrum below it1 will condense the vapour thickly1 while the portion corresponding with the other rays will be left untouched4 ,this affords us evidence of the power of solar heat to produce1 very readily1 a change in the molecular structure of solid bodies4 ,if we allow the sun's rays to permeate coloured glasses1 and then fall upon a polished metallic surface1 the result1 on exposing the plate to vapourisation1 will be similar to that just described4 ,under yellow and green glasses no vapour will be condensed2 but on the space on which the rays permeating a red glass1 or even a blackened one1 fall1 a very copious deposit of vapour will mark with distinctness the spaces these glasses covered4 ,more remarkable still1 if these or any other coloured bodies are placed in a box1 and a polished metal plate is suspended a few lines above them1 the whole being kept in perfect darkness for a few hours1 precisely the same effect takes place as when the arrangement is exposed to the full rays of the sun4 ,here we have evidence of the radiating heat of bodies1 producing even in darkness the same phenomena as the transmitted heat-rays of the sun4 ,we must1 however1 return to the examination of some of these and other analogous influences under the head of actino-chemistry4 ,from these curious discoveries of inductive research we learn some high truths4 ,associated with light--obeying many of the same laws--moving in a similar manner--we receive a power which is essential to the constitution of our planet4 ,this power is often manifested in such intimate combination with the luminous principle of the solar rays1 that it has been suspected to be but another form of the same agency4 ,while1 however1 we are enabled to show the phenomena of one without producing those which distinguish the other1 we are constrained to regard heat as something dissimilar to light4 ,it is true that we appear to be tending towards some point of proof on this problem2 but we are not in a position to declare them to be forms of one common power1 or 8particular solutions of one great physical equation40#ei ,in many instances it would certainly appear that one of these forces was directly necessary to the production of the other2 but we have also numerous examples in which they do not stand in any such correlation4 ,we learn1 from the scientific facts which we have been discussing1 a few of the secrets of natural magic4 ,in their relations to heat1 every flower1 which adds to the adornment of the wilds of nature or the carefully-tended garden of the florist1 possesses a power peculiar to itself2 8,naiad-like lily of the vale10 and1 8---- ,the pied wind-flowers1 and the tulip tall1 ,and narcissi1 the fairest among them all10 are1 by their different colours1 prevented from ever having the same temperatures under the same sunshine4 ,every plant bears within itself the measure of the heat which is necessary for its well-being1 and is endued with functions which mutely determine the relative amount of dew which shall wet its coloured leaves4 ,some of the terrestrial phenomena of this remarkable principle will still further illustrate the title of this volume4 ,to commence with the most familiar illustrations1 let us consider the consequences of change of temperature4 ,however slight the additional heat may be to which a body is subjected1 it expands under its influence2 consequently1 every atom which goes to form the mass of the earth moves under the excitation1 and the first heat ray of the morning which touches the earth's surface1 sets up a vibration which is continued as a tremor to its very centre4 ,the differences between the temperature of day and night are considerable2 therefore all bodies expand under the influence of the higher1 and contract under that of the lower temperature4 ,during the day1 any cloud obscuring the sun produces1 in every solid1 fluid1 or ariform body1 within the range of solar influence1 a check3 the particles which had been expanding under the force of heat suddenly contract4 ,thus there must of necessity be1 during the hours of sunshine1 a tendency in all bodies to dilate1 and during the hours of night they must be resuming their original conditions4 ,not only do dissimilar bodies radiate heat in different degrees1 but they conduct it also with constantly varying rates4 ,heat passes along silver or copper with readiness1 compared to its progress through platinum4 ,it is conducted by glass but slowly1 and still more slowly by wood and charcoal4 ,we receive some important intimations of the molecular structure of matter1 from those experiments which prove that heat is conducted more readily along some lines than others4 ,in some planes1 wood and other substances are better conductors than in others4 ,the metallic oxides or earths are bad conductors of heat1 by which provision the caloric absorbed by the sun's rays is not carried away from the surface of this planet so rapidly as it would have been had it been of metal1 but is retained in the superficial crust to produce the due temperature for healthful germination and vegetable growth4 ,the wool and hair of animals are still inferior conductors1 and thus1 under changes of climate and of seasons1 the beasts of the field are secured against those violent transitions from heat to cold which would be fatal to them4 ,hair is a better conductor than wool3 hence1 by nature's alchemy1 hair changed into wool in the animals of some countries on the approach of winter1 and feathers into down4 ,it is therefore evident that the rate at which solar heat is conducted into the crust of the earth must alter with the condition of the surface upon which it falls4 ,the conducting power of all the rocks which have been examined is found to vary in some degree4#fj ,it follows1 as a natural consequence of the position of the sun to the earth1 that the parts near the equator become more heated than those remote from it4 ,as this heat is conducted into the interior of the mass1 it has a tendency to move to the colder portions of it1 and thus the heat absorbed at the equator flows towards the poles1 and from these parts is carried off by the atmosphere1 or radiated into space4 ,owing to this1 there is a certain depth beneath the surface of our globe at which an equal temperature prevails1 the depth increasing as we travel north or south from the equator1 and conforming to the contour of the earth's surface1 the line sinking under the valleys and rising under the hills4#fa ,a question of great interest1 in a scientific point of view1 is the temperature of the centre of the earth4 ,we are1 of course1 without the means of solving this problem2 but we advance a little way onwards in the inquiry by a careful examination of subterranean temperature at such depths as the enterprise of man enables us to reach4 ,these researches show us1 that where the mean temperature of the climate is #ej1 the temperature of the rock at #ei fathoms from the surface is #fj2 at #acb fathoms it is #gj2 at #bci fathoms it is #hj3 being an increase of #aj at #ei fathoms deep1 or #a in #ced feet2 of #aj more at #gc fathoms deeper1 or #a in #dch feet2 and of #aj more at #aad fathoms still deeper1 or #a in #fdb feet4#fb ,although this would indicate an increase to a certain depth of about one degree in every fifty feet1 yet it would appear that the rate of increase diminishes with the depth4 ,it appears therefore probable1 that the heat of the earth1 so far as man can examine it1 is due to the absorption of the solar rays by the surface4 ,the evidences of intense igneous action at a great depth cannot be denied1 but the doctrine of a cooling mass1 and of the existence of an incandescent mass1 at the earth's centre1 remains but one of those guesses which active minds delight in4 ,the mean annual temperature of this planet is subject to variations1 which are probably dependent upon some physical changes in the sun himself1 or in the atmospheric envelope by which that orb is surrounded4 ,the variations over the earth's surface are great4 ,at the equator we may regard the temperature as uniformly existing at #hj1 while at the poles it is below the freezing point of water2 and as far as observations have been made1 the subterranean temperatures bear a close relation to the thermic condition of the climate of the surface4 ,the circulation of water through faults or fissures in the strata is1 without doubt1 one means of carrying heat downwards much quicker than it would be conducted by the rocks themselves4 ,it is not1 however1 found that the quantity of water increases with the depth4 ,in the mines of ,cornwall1 unless where the ground is very loose1 miners find that1 after about #aej fathoms 7#ijj feet71 the quantity of water rapidly diminishes4 ,that water must ascend from very much greater depths is certain1 from the high temperatures at which many springs flow out at the surface4 ,in the ,united ,mines in ,cornwall1 water rises from one part of the lode at #ij2 and one of the levels in these workings is so hot that1 notwithstanding a stream of cold water is purposely brought into it to reduce the temperature1 the miners work nearly naked1 and will bathe in water at #hj to cool themselves4 ,at the bottom of ,tresavean ,mine1 in the same county1 about #cbj fathoms from the surface1 the temperature is #ajj4 ,one cause of the great heat of many of our deep mines1 which appears to have been entirely lost sight of1 is the chemical action going on upon large masses of pyritic matter in their vicinity4 ,the heat1 which is so oppressive in the ,united ,mines1 is1 without doubt1 due to the decomposition of immense quantities of the sulphurets of iron and copper known to be in this condition at a short distance from these mineral works4 ,the heat which man is enabled to measure beneath the earth's surface1 appears to be alone due to the conducting powers of the rocks themselves2 it has been observed that the line of equal temperature follows1 as nearly as possible1 the elevations and depressions which prevail upon the surface1 and the diminishing rate of increase beyond this line1 certainly is such as would arise1 was all the heat so measured1 the result of the passage of the heat by conduction through the crust of rocks4 ,whether or not the subterranean bands of equal heat have any strict relation1 upon a large scale1 to the isothermic lines which have been traced around most portions of our globe1 is a point which has not yet been so satisfactorily determined as to admit of any general deductions4 ,the ,oriental story-teller makes the inner world a place of rare beauty--a cavern temple1 bestudded with self-luminous gems1 in which reside the spiritual beings to whom the direction of the inorganic world is confided4 ,the ,philosopher1 in the height of his knowledge1 has had dreams as absurd as this2 and amid the romances of science1 there are not to be found any more strange visions than those which relate to the centre of our globe4 ,at the same time it must be admitted1 that many of the peculiar phenomena which modern geological researches have brought to light1 are best explained on the hypothesis of a cooling sphere1 which necessarily involves the existence of a very high temperature towards the centre4 ,we have already noticed some remarkable differences between solar and terrestrial heat2 but a class of observations by ,delaroche#fc still requires our attention4 ,solar heat passes freely through colourless glass1 whereas the radiations from a bright fire or a mass of incandescent metal are entirely obstructed by this medium4 ,if we place a lamp or a ball of glowing hot metal before a metallic reflector1 the focus of accumulated heat is soon discovered2 but if a glass mirror be used1 the light is reflected1 but not the heat2 whereas1 with the solar rays1 but little difference is detected1 whether vitreous or metallic reflectors are employed4 ,it is well known that glass lenses refract both the light and heat of the sun1 and they are commonly known as burning-glasses3 the heat accumulated at their focal point being of the highest intensity4 ,if1 instead of the solar beam1 we employ1 in our experiments1 an intense heat produced by artificial means1 the passage of it is obstructed1 and the most delicate thermometers remain undisturbed in the focus of the lens4 ,glass exposed in front of a fire becomes warm1 and by conduction the heat passes through it1 and a secondary radiation takes place from the opposite side4#fd ,it has been found that glass is transcalescent1 or diathermic1 to some rays of terrestrial heat1 and adiathemic1 or opaque for heat1 to others#fe--that the capability of permeating glass increases with the temperature of the ignited body--and that rays which have passed one screen traverse a second more readily4 ,it would1 however1 appear that something more than a mere elevation of temperature is necessary to give terrestrial heat-radiations the power of passing through glass screens1 or1 in other words1 to acquire the properties of solar heat4 ,to give an example4 ,the heat of the oxy-hydrogen flame is most intense1 yet glass obstructs it1 although it may be assisted by a parabolic reflector4 ,if this flame is made to play upon a ball of lime1 by which a most intense light is produced1 the heat1 which has not been actually increased1 acquires the power of being refracted by a glass lens1 and combustible bodies may be ignited in its focus4 ,it certainly appears from these results1 that the undulatory hypothesis holds true1 so far as the motion of the calorific power is concerned4 ,at a certain rate the vibrations are thrown back or stopped by the opposing body1 while in a state of higher excitation1 moving with increased rapidity1 they permeate the screen4#ff ,this does not1 indeed1 interfere with the refined theory of ,prvost1#fg which supposes a mutual and equal interchange of caloric between all bodies4 ,the most general effect of heat is the expansion of matter2 solids1 liquids1 and airs1 all expand under its influence4 ,if a bar of metal is exposed to calorific action1 it increases in size1 owing to its particles being separated farther from each other3 by continuing this influence1 after a certain time the cohesion of the mass is so reduced that it melts1 or becomes liquid1 and1 under the force of a still higher temperature1 this molten metal may be dissipated in vapour4 ,it would appear as if1 under the agency of the heat applied to a body1 its atoms expanded1 until at last1 owing to the tenuity of the outer layer or envelope of each atom1 they were enabled to move freely over each other1 or to interpenetrate without difficulty4 ,that heat does really occasion a considerable disturbance in the corpuscular arrangement of bodies1 may be proved by a very interesting experiment4 ,a bar of heated metal is placed to cool1 with one end supported upon a wedge or a ring of a different metal the other resting on the ground4 ,in cooling1 a distinct musical sound is given out1 owing to the vibratory action set up among the particles of matter moving as the temperature declines4#fh ,heat is diffused through all bodies in nature1 and1 as we shall presently see1 may be developed in many different ways4 ,we may1 therefore1 infer1 that in converting a sphere of ice into water1 and that again into steam1 we have done nothing more than interpenetrate the mass with a larger quantity of heat1 by which its atoms are more widely separated1 and that thus its molecules become free to move about each other4 ,hence1 from a solid state1 the water becomes fluid2 and then1 if the expansive force is continued1 an invisible vapour4 ,if these limits are passed by the powers of any greatly increased thermic action1 the natural consequence1 it must be seen1 will be the separation of the atoms from each other1 to such an extent that the molecule is destroyed1 and chemical decomposition takes place4 ,by the agency of the electricity of the voltaic battery1 we are enabled to produce the most intense heat with which we are acquainted1 and by a peculiarly ingenious arrangement ,mr4 ,grove has succeeded in resolving water by the mere action of heat into its constituent elements--oxygen and hydrogen gases4 ,that this decomposition is not due to the voltaic current1 but to the heat produced by it1 was subsequently proved by employing platina heated by the oxy-hydrogen flame4#fi ,this interesting question has been examined with great care by ,dr4 ,robinson of ,armagh1 who has shown that1 as the temperature of water is increased1 the affinity of its elements is lessened1 until at a certain point it is eventually destroyed4 ,this new and startling fact appears scarcely consistent with our knowledge that a body heated so as to be luminous has the power of causing the combination of the elements of water with explosive violence4#gj ,but as this acute experimental philosopher somewhat boldly but still most reasonably inquires3 8,is it not probable that1 if not light1 some other actinic power 7like that which accompanies light in the spectrum1 and is revealed to us by its chemical effects in the processes of photography7 is evolved by the heat1 and1 though invisible1 determines1 in conjunction with the affinity1 that atomic change which transforms the three volumes of oxygen and hydrogen into two of steam80#ga ,this speculation explains1 in a very satisfactory manner1 some results which were obtained by ,count ,rumford1 in #agih4 ,in a series of experiments instituted for the purpose of examining 8those chemical properties of light which have been attributed to it10 he has shown that many cases of chemical decomposition occur in perfect darkness1 under the influence of heat1 which are precisely similar to those produced by exposure to the sun's rays4#gb ,it must1 however1 be remembered1 that both solar light and heat are sometimes found in direct antagonism to actinic power1 and that the most decided chemical changes are produced by those rays in which neither heat nor light can be detected4 ,the most remarkable phenomena of this class will be explained under the head of actinism4 ,one of the most curious relations which as yet have been discovered between light and heat is1 that1 the temperature at which all bodies become incandescent1 excepting such as are phosphorescent1 is uniform4 ,the point on the thermometer 7,fahrenheit's scale7 when the eye by perfect repose is enabled to detect the first luminous influence1 may probably be regarded as1 or very near1 #ajjj4 ,daniel has fixed this point at #ihj1 ,wedgwood at #idg1 and ,draper at #igg4gc ,dr4 ,robinson and ,dr4 ,draper1 by independent observations1 have both arrived at the conclusion1 that the first gleam of light which appears from heated platina is not red1 but of a lavender gray1 the same in character of colour as that detected by ,sir ,john ,herschel among the most refrangible rays of the solar spectrum4#gd ,it must be admitted1 that the question of the identity1 or otherwise1 of light and radiant heat1 is beset with difficulties4 ,many of their phenomena are very similar--many of their modes of action are alike3 they are often found as allied agencies2 but they as frequently exhibit extreme diversity of action1 and they may be separated from each other4 ,we have now examined the physical conditions and properties of this most important element1 and we must proceed to learn something of the means by which it may be developed1 independently of its solar source4 ,this extraordinary principle exists in a latent state in all bodies1 and may be pressed out of them4 ,the blacksmith hammers a nail until it becomes red hot1 and from it he lights the match with which he kindles the fire of his forge4 ,the iron has by this process become more dense1 and percussion will not again produce incandescence until the bar has been exposed in fire to a red heat4 ,the only inference we can draw from this result is1 that by hammering the particles have been driven closer together1 and the heat driven out2 now further hammering will not force the atoms nearer1 and consequently no additional quantity of heat can be developed2 the iron is made hot in a fire1 it absorbs heat1 the particles are restored to their former state1 and we can now again by hammering develope both heat and light4 ,the ,indian produces a spark by the attrition of two pieces of wood4 ,by friction1 two pieces of ice may be made to melt each other2 and could we1 by mechanical pressure1 force water into a solid state1 an immense quantity of heat would be set free4 ,by the condensation of hydrogen and oxygen gases1 pulverulent platinum will become glowing red-hot1 and1 with certain precautions1 even the compact metal1 platinum1 itself2 the heat being derived from the gases1 the union of which it has effected4 ,a body passing from the solid to the fluid state absorbs heat from all surrounding substances1 and hence a degree of cold is produced4 ,the heat which is thus removed is not destroyed--it is held combined with the fluid2 it exists in a latent state4 ,fluids1 in passing into a gaseous form1 also rob all surrounding bodies of an amount of heat necessary to maintain the ariform condition4 ,from the air or from the fluid1 this heat may1 as we have shown above1 be again extracted4 ,locked in a pint measure of air1 there exists sufficient heat to raise several square inches of metal to glowing redness4 ,by the compression of atmospheric air this may be shown1 and with a small condensing syringe a sufficient quantity of heat may be set free to fire the ,boletus igniarius1 which1 impregnated with nitre1 is known as amadou4 ,we are acquainted with various sources from which heat may be developed for artificial purposes3 the flint-and-steel is an example of the production of heat by mechanical force1 and the modern lucifer-match1 of the combined action of friction and chemical affinity4 ,these of themselves would admit of a lengthened discourse2 but it is necessary that we carefully examine some of the less familiar phenomena of heat under the influences of changes of chemical condition4 ,if spirits of wine and water are mixed together1 a considerable degree of heat is given out1 and by mixing sulphuric acid and water1 an infinitely larger quantity4 ,if sulphuric acid 7oil of vitriol7 and spirit of wine1 or nitric acid 7aquafortis7 and spirits of turpentine1 at common temperatures1 be suddenly mixed1 so much heat is set free as to ignite the spirit4 ,in each of these instances there is a condensation of the fluid4 ,in nearly all cases of solution1 cold is produced by the absorption of the heat necessary to sustain the salt in a liquid form2 but when potash dissolves in water1 heat is given out1 which is a fact we cannot yet explain4 ,if potassium is placed on water1 it seizes the oxygen of the water and sets fire to the hydrogen gas liberated by the heat produced in the change of form4 ,antimony and many other metals thrown into chlorine gas ignite and burn with brilliancy3 the same phenomenon takes place in the vapours of iodine or bromine4 ,many chemical combinations1 as the chloride of potassium and sulphur explode with a blow2 whilst the slightest friction occasions the detonation of the fulminating salts of silver1 mercury1 and gold4 ,compounds of nitrogen and chlorine1 or iodine1 are still more delicately combined--the former exploding with fearful violence on the contact of any oleaginous body1 and the latter by the smallest elevation of temperature3 both of them destroying the vessels in which they may be contained4 ,gun cotton presents some peculiar phenomena which may merit brief attention4 ,this peculiar compound is prepared by the action of nitric acid on cotton fibre4 ,the general appearance of the cotton is not altered1 but a remarkable physical change has taken place4 ,it is now soluble in ether1 and forms a gelatinous compound3--it explodes violently at a temperature which is insufficient for the combustion of gunpowder4 ,indeed1 from1 as it would appear1 slight electrical disturbances taking place in the gun cotton itself1 it not unfrequently explodes spontaneously4 ,these fearful disturbances of the forces which hold bodies in combination are explained with difficulty4 ,may it not be1 that an enormous quantity of the calorific and chemical principles is held in a state of extreme tension around the particles of the compound1 and that the equilibrium being destroyed1 the whole is developed in destructive rapidity8 ,the fact of great heat being evolved during the conversion of a body from a solid to a gaseous state1 as in the explosion of gunpowder or gun cotton1 which is a striking exception to the law of latent heat1 as it prevails in most cases1 admits of no more satisfactory explanation4 ,as mechanical force produces calorific excitation1 so we find that every movement of sap in vegetables1 and of the blood and fluids in the animal economy1 causes a sensible increase of heat4 ,the chemical processes constantly going on in plants and animals are another source of heat1 in addition to which nervous energy and muscular movement must be regarded as producing the caloric which is essential to the health and life of the latter4 ,digestion has been considered as a process of combustion2 and the action between the elements of food1 and the oxygen conveyed by the circulation of the blood to every part of the body1 regarded as the source of animal heat2 and1 without doubt1 it is one great source1 although it can scarcely be regarded as the only one4#ge ,the vis vit1 or vital power1 influences the delicate and beautiful system of nerves2 and as life 7an essence of the rarest and most subtile order1 a diffusive influence7 runs through them1 from the brain to the extremities of the members of the body1 it sets those tender threads in rapid vibration1 and heat is developed4 ,by this action1 the circulation of the blood is effected2 the muscle is maintained in an elastic condition1 ready to perform the tasks of the will2 and through these agencies is the warm and fluid blood fitted to receive its chemical restoratives in the lungs1 and the stomach to support changes for which it is designed--chemical also--by which more heat is liberated4 ,was digestion--,eremacausis1 as the slow combustion produced by combination with oxygen is called--the only source of animal heat1 why should the injury of one filmy nerve place a member of the body for ever in the condition of stony coldness8 ,or why1 chemical action being most actively continued after a violent death1 by the action of the gastric juices upon the animal tissues1 should not animal heat be maintained for a much longer period than it is found to be after respiration has ceased8#gf ,in studying the influences of caloric upon the conditions of matter1 we must regard the effects of extreme heat1 and also of the greatest degrees of cold which have been obtained4 ,there are a set of experiments by the ,baron ,cagniard de la ,tour1 which appear to have a very important bearing on some conditions that may be supposed to prevail in nature1 particularly if we adopt the view of a constantly increasing temperature towards the centre of our earth4 ,if water1 alcohol1 or ether1 is put into a strong glass tube of small bore1 the ends hermetically sealed1 and the whole exposed to a strong heat1 the fluid disappears1 being converted into a transparent gas2 but1 upon cooling1 it is again condensed1 without loss1 into its original fluid state4#gg ,in this experiment1 fluid bodies have been converted into elastic transparent gases with but small change of volume1 under the pressure of their own atmospheres4 ,we can readily conceive a similar result occurring upon a far more extensive scale4 ,in volcanic districts1 at great depths1 and consequently under the pressure of the superincumbent mass1 the siliceous rocks1 or even metals1 may1 from the action of intense heat1 be brought into a fluid1 or even a gaseous condition1 without any change of volume1 since the elastic force of heat is opposed by the rigid resistance of the pressure of the surrounding rocks4 ,some beautiful experiments by ,mr4 ,hopkins1 of ,cambridge1 have proved that the temperature necessary to melt a body must be considerably elevated as the mechanical pressure to which it is subjected is increased4 ,directly connected with the results of ,cagniard de la ,tour are a yet more remarkable set of phenomena1 which have been investigated by ,m4 ,boutigny1#gh and generally known as the 8spheroidal condition0 of bodies4 ,if water is projected upon very hot metal it instantly assumes a spheroidal form--an internal motion of its particles may be observed--it revolves with rapidity1 and evaporates very slowly4 ,if a silver or platinum capsule1 when brought to a bright red heat1 is filled with cold water1 the whole mass assumes the spheroidal state1 the temperature of the fluid remaining considerably below the boiling point1 so long as the red heat is maintained4 ,if we allow the vessel to cool below redness in the dark1 the water then bursts into active ebullition1 and is dissipated into vapour with almost explosive violence4 ,an equal quantity of water being projected into two similar vessels1 over the fire1 one cold and the other red hot1 it will be found that the water in the cold vessel will boil and evaporate long before that in the one which is red hot4 ,another form of this experiment is exceedingly instructive4 ,if a mass of white hot metal is suddenly plunged into a vessel of cold water1 the incandescence is not quenched1 the metal shines with a bright white light1 and the water is seen to circulate around1 but at some distance from the glowing mass1 being actually repelled by calorific agency4 ,at length1 when the metal cools1 the water comes in contact with it1 and boils with energy4 ,a result similar to this was observed by ,perkins1 but its correctness most unjustly doubted4 ,having made an iron shell containing water1 and carefully plugged up1 white hot1 it was found that the steam never exerted sufficient force to burst the vessel1 as it was expected it would do4 ,he caused a hole to be drilled into the bottom of the white-hot shell1 and he was surprised to find that no water flowed through the orifice1 until the iron was considerably cooled1 when it issued forth with violence in the form of steam4 ,here we have the ,cagniard de la ,tour state first induced1 and the calorific repulsion of the spheroidal state supervenes4 ,if water is poured upon an iron sieve1 the wires of which are made red hot1 it will not percolate2 but on cooling1 it runs through rapidly4 ,m4 ,boutigny1 pursuing this curious inquiry1 has recently proved that the moisture upon the skin is sufficient to protect it from disorganization1 if the arm is plunged into baths of melted metal4 ,the resistance of the surfaces is so great1 that little elevation of temperature is experienced4#gi ,professor ,plcker1 of ,bonn1 has stated that by washing the arm with ether previously to plunging it into melted metal1 the sensation produced1 while in the molten mass1 is that of freezing coldness4 ,we have now seen that heat at different degrees of intensity appears to produce chemical composition--that it decomposes combined elements--that it alters the conditions of bodies1 and actually maintains so powerfully a repellent force1 that fluids cannot touch the heated body4 ,more than this1 it exerts a most powerful antagonistic influence over all chemical relations4 ,if1 to give one example1 the volatile element iodine is put into a glowing hot capsule1 it resolves itself immediately into a spheroid4 ,potash rapidly combines with iodine2 but if a piece of this alkali is thrown upon it in the capsule1 it also takes the spheroidal form1 and both bodies revolve independently of each other1 their chemical affinities being entirely suspended2--but allow the capsule to cool1 and they combine immediately4 ,science teaches us that a temperature so exalted as not to burn organic bodies may be produced1 and points to us this remarkable fact1 that the destructive limits of heat are measured between certain degrees--beyond which a fire1 by reason of its intensity1 ceases to develope heat4 ,what is the radiant force into which this principle changes8 ,the experiments of ,cagniard de la ,tour and of ,boutigny 7d',evreux71 connect themselves1 in a striking manner1 with those of ,mr4 ,grove and ,dr4 ,robinson2 and they teach us that but a very slight alteration in the proportions of the calorific principle given to this planet would completely change the character of every material substance of which it is composed1 unless there was an alteration in the physical condition of the elements themselves4 ,supposing the ordeal of fiery purification to take place upon this earth1 these experiments appear to indicate the mighty changes which would thence result4 ,there would be no annihilation1 but everything would be transformed from the centre of the globe to the verge of its atmosphere--old things would pass away1 all things become new1 and the beautiful mythos of the phnix be realized in the fresh creation4 ,the deductions to be drawn from the results obtained by abstracting heat from bodies are equally instructive4 ,by taking advantage of the cooling produced by the rapid solution of salts of several kinds in water1 an intense degree of coldness may be produced4#hj ,indeed1 the absorption of heat by liquefaction may be shown by the use of metallic bodies alone4 ,if lead1 tin1 and bismuth1 are melted together1 and reduced to a coarse powder by being poured into water1 and the alloy then dissolved in a large quantity of quicksilver1 the thermometer will sink nearly #ej degrees4 ,an intense amount of cold will result from the mixture of muriate of lime and snow1 by which a temperature of #ej below the zero of ,fahrenheit1 or #hb below the freezing point of water1 is produced4 ,by such a freezing mixture as this1 mercury will be rendered solid4 ,a degree of cold1 however1 far exceeding it1 has lately been obtained by the use of solid carbonic acid and ether4#ha ,solid carbonic acid is itself procured from the gas liquefied by pressure2 which liquid1 when allowed to escape into the air1 evaporates so rapidly that a large quantity of it is congealed by being robbed of its combined heat by the vaporizing portion4 ,when this solid acid is united with ether1 a bath is formed in which the carbonic acid will remain solid for twenty or thirty minutes4 ,by a mixture of this kind1 placed under the receiver of an air-pump1 a good exhaustion being sustained1 a degree of cold #aff below zero is secured4 ,by this intense cold1 many of the bodies which have hitherto been known to us only in the gaseous state have been condensed into liquids and solids4 ,olefiant gas1 a compound of hydrogen and carbon1 was brought into a liquid form4 ,hydriodic and hydrobromic acids could be condensed into either a liquid or a solid form4 ,phosphuretted hydrogen1 a gas which inflames spontaneously when brought into contact with the air or with oxygen1 became a transparent liquid at this great reduction of temperature4 ,sulphurous acid may be condensed1 by pressure and a reduction of temperature1 into a liquid which boils at #ad ,fahrenheit1 but by the carbonic acid bath it is converted into a solid body1 transparent and without colour4 ,sulphuretted hydrogen gas solidifies at #abb below zero1 and forms a white substance resembling a mass of crystals of sea-salt4 ,a combination of the two gases1 chlorine and oxygen1 becomes solid at -#ge1 and the protoxide of nitrogen at -#aej4 ,cyanogen1 a compound of carbon and nitrogen--the base of prussic acid--is solidified at #cj below the zero of our thermometric scale4 ,the well-known pungent compound1 ammonia1 so exceedingly volatile at common temperatures1 is converted into a crystalline1 translucent1 white substance at the temperature of -#ajc4 ,the difficulties which necessarily attend the exposure of a body to extreme cold and great pressure at the same time1 appear to be the only obstacle to the condensation of oxygen1 hydrogen1 and nitrogen gases4 ,a sufficient amount of condensation was1 however1 effected by ,dr4 ,faraday1 to lead him to the conclusion1 arrived at also by other evidences1 that hydrogen1 the lightest of the ponderable bodies1 partakes of the nature of a metal4#hb ,during the solidification of water by freezing1 some remarkable facts may be noticed4 ,water1 in cooling1 gradually condenses in volume until it arrives at #dj ,fahr41 which appears to be the point of greatest density4 ,from this temperature to that of #cb1 the point at which it begins to solidify1 its volume remains unchanged1#hb as crystallisation 7freezing7 begins1 the bulk increases1 the mass becomes specifically lighter1 and it swims on the surface of the fluid4 ,from #dj to #cb the particles of water must be taking up that new position which is essential to the formation of the solid--ice2 and while this is taking place1 every substance held in solution by the water is rejected4 ,if we mix with water the deepest colouring matter--the strongest acid or the most acrid poison--they are each and all rejected during the process of freezing1 and if the water has been kept in a state of agitation during the process--so that the liberated particles may not be mechanically entangled--the ice will be transparent1 colourless1 tasteless1 and inert--the substances rejected being gathered together in the centre of the frozen mass in a state of intense concentration4 ,in like manner1 even the atmospheric air1 which is always held in solution1 is rejected1 and hence the reason why all the ice which forms upon still ponds is full of air-bubbles1 while the ice which is produced in agitated water is perfectly free from them4 ,this in itself is a remarkable condition1 the entire bearing of which is not clearly understood2 but a still more singular fact has been discovered in intimate connection with the rejection of all matter from a freezing solution4 ,water1 which in this way is freed entirely of air1 will not boil at #bab ,f41 the ordinary boiling point of water4 ,if a mass of ice formed in the manner described is placed in a vessel1 and being just covered with a film of oil1 to prevent the absorption of air1 is melted over a lamp or fire1 and the heat continued1 it will1 so far from being converted into steam at #bab1 continue to increase in temperature up to #bgj or more1 and then burst into ebullition with such explosive violence as to rend the vessel in which it is confined4 ,from this experiment we learn that did water exist in any other condition than that in which we find it--even with the apparently simple difference of containing no air--it would not be safe to employ it in any culinary or manufacturing operation1 since its use would be followed by explosions as dangerous as those of gunpowder4 ,such researches as these prove to us the admirable adaptation of all things to their especial ends--the beautiful adjustment of the balance of forces throughout creation4 ,the refinements of ,grecian philosophy saw1 without the aids of inductive science1 that the outward vesture of nature covered a host of mysterious agencies to which its characteristics were directly due4 ,in their dream of the four elements1 fire1 the external and visible form of heat1 was regarded as the cause of vitality1 and the disposer of every organised and unorganised condition of matter4 ,their idealisations have assumed another form1 but the researches of modern science have only established their universality and truth4 ,the great agents at work in nature--the mighty spirits bound to never-ending tasks1 which they pursue with unremitting toil1 are of so refined a character1 that they will probably remain for ever unknown to us4 ,the arch-evocator1 with the wand of induction1 calls2 but the only answer to his evocation is the manifestation of power in startling effects4 ,science pursues her inquiries with zeal and care3 she tries and tortures nature to compel her to reveal her secrets4 ,bounds are1 however1 set to the powers of mortal search3 we may not yet have reached the limits within which we are free to exercise our mental strength2 but1 those limits reached1 we shall find an infinite region beyond us1 into which even conjecture wanders eyeless and aimless1 as the blind ,cyclops groping in his melancholy cave4#hc ,all we know of heat is1 that striking effects are produced which we measure by sensation1 and by instruments upon which we have observed that given results will be produced under certain conditions3 of anything approaching to the cause of these we are totally ignorant4 ,the wonder-working mover of some of the grandest phenomena in nature--giving health to the organic world1 and form to the inorganic mass--producing genial gales and dire tornadoes--earthquake strugglings and volcanic eruptions--ministering to our comforts in the homely fire1 and to advancement in civilisation in the mighty furnace1 and the ingenious engine which drains our mines1 or traverses our country with bird-like speed1--will1 in all probability1 remain for ever unknown to man4 ,the immortal ,newton1 many of whose guesses have a prophetic value1 thus expresses himself3--8,heat consists in a minute vibratory motion in the particles of bodies1 and this motion is communicated through an apparent vacuum by the undulations of a very subtile elastic medium1 which is also concerned in the phenomena of light40 ,our experimental labours and our mathematical investigations have considerably advanced our knowledge since the time of ,newton2 yet still each theory of heat strangely resembles the mystic lamp which the ,rosicrucian regarded as a type of eternal life--a dim and flickering symbol1 in the tongue-like flame of which imagination1 like a child1 can conjure many shapes4 ,modern theory regards heat as a manifestation of motion1 and experiment proves that a body falling through a certain space generates a definite quantity of heat1 while observation shows that the waters at the base of the ,falls of ,niagara possess a temperature #a higher than when they first glide over the edge of the precipice4 ,this increase of temperature is due to the mechanical force due to the fall1 and is no more an evidence of the conversion of motion into heat1 than is the old experiment of rubbing a button until it becomes hot4 ,at all events1 the fact that a given amount of mechanical force always produces an equivalent of heat is as applicable to the idea of a 8subtile elastic medium0 which is diffused through all matter1 as to the1 at present1 favourite hypothesis4 ,so far has this view been strained1 that the temperature of the planets has been referred to their motions1 and speculation has aided the mathematician in determining the cessation of planetary motion1 by the conversion of it into heat4 ,it is true that other theorists have supposed points in space upon which this heat might be concentrated and reflected back again to produce motion4 ,there may be much of the poetic element in such speculations1 but it is of that order which belongs rather to the romantic than to the real4 ,a speculation which has more of truth1 and which is1 indeed1 demonstrable1 cannot fail to impress every mind with its beauty1 and probable correctness4 ,in the growth of a tree1 its wood and all its products are the result of certain external forces effecting chemical changes4 ,carbonic acid is decomposed1 the carbon is retained1 and oxygen given off1 and assimilations of a complex character are in constant progress to produce the various compounds of oxygen1 hydrogen1 nitrogen1 and carbon4 ,every condition of organised forms is due to the external excitation of light and heat1 and in the chemical changes which take place1 an equivalent of these principles1 or powers--it signifies but little according to which view we may regard them--is absorbed1 and retained as essential to the condition of the matter formed4 ,let us confine our attention to wood--although the position applies equally to every organic product4 ,a cubic foot of wood is formed by the decomposition of a certain quantity of carbonic acid1 by the vital function of the plant1 excited by the solar rays1 which are involved in the mass which nature by 8her wondrous alchemy0 has made4 ,eventually this cubic foot of wood is subjected to a process of chemical change--combustion2 by the application of a single spark1--and in the disintegration of the wood1 its carbon combining with oxygen to form carbonic acid1 its hydrogen to form water1 which is returned to the air1 a large amount of light and heat is produced4 ,this is exactly equivalent to the amount which was engaged in its formation4 ,indeed1 the sunshine which fell upon the leaves of the forest tree1 of which the log formed a part1 has been hoarded up1 and we again develope it in its original state of heat and light4 ,the vast coal beds of ,england were formed by the rapid growth and quick decay of a peculiar class of plants under the influence of a tropical sun4 ,they have been buried myriads of ages1 under hundreds of feet of sandy rock4 ,by the industry of the miner the coal is brought again to the surface1 and we develope from it those powers by which it was formed4 ,in the fire which gives comfort to our homes--in the furnace which generates force for the purposes of manufacture1 or to propel the railway engine and its ponderous train--in the gas with which we illumine our streets and gladden during the long winter nights our apartments1 we are developing that heat and light which fell upon the earth with all its quickening influences millions of ages before yet the ,creator had called into existence the monarch ,man1 for whose necessities these wondrous formations were designed4 ,,footnotes3 #dc ,the following table of the rays penetrating coloured glass has been given by ,melloni1 in his memoir ,on the ,free ,transmission of ,radiant ,heat through ,different ,bodies3-- ,deep violet #ec ,yellowish red 7flaked7 #ec ,purple red 7flaked7 #ea ,vivid red #dg ,pale violet #de ,orange red #dd ,clear blue #db ,deep yellow #dj ,bright yellow #cd ,golden yellow #cc ,deep blue #cc ,apple green #bf ,mineral green #bc ,very deep blue #ai ,translated in the ,scientific ,memoirs1 vol4 i4 p4 #cj4 #dd 8,the physical characters of this species of glass1 which acts so differently from the other species of coloured glass in all the phenomena of calorific absorption1 are1 #ast1 its intercepting almost totally the rays which pass through alum2 #bnd1 its entirely absorbing the red rays of the solar spectrum4 ,i have already stated that their colouration is produced almost entirely by the oxide of copper4 8,thus1 the colouring matters of the coloured glasses1 while they so powerfully affect the relations of quantity which the different rays of ordinary light bear to each other1 exercise no elective action on the concomitant calorific rays4 ,this curious phenomenon is the more remarkable as the colouring matters absorb almost always a very considerable portion of the heat naturally transmitted by the glass4 ,the following are1 in fact1 the calorific transmissions of the seven coloured glasses referred to2 the transmission of the common glass being represented by #ajj2 red glass1 #hbe2 orange1 #gbe2 yellow1 #ee2 bluish-green1 #ege2 blue1 #ebe2 indigo1 #cj2 violet1 #he4 ,the quantity of heat absorbed through the action of the colouring substances is1 therefore1 #age in the red glass1 #bge in the orange1 #de in the yellow1 #dbe in the green1 #dge in the blue1 #gj in the indigo1 and #ae in the violet4 ,now1 as these absorptions extinguish a proportional part of each of the rays which constitute the calorific stream transmitted by common glass1 they may be compared1 as we said before1 with the absorbent action exercised on light by matters more or less deeply brown or dark1 when they are immersed in water1 or some other colourless liquid which dissolves1 but does not affect them chemically40--,annales de ,chimie et de ,physique1 tom4 xl4 p4 #chb4 ,guided by these principles1 the author selected the glass employed in glazing the ,royal ,palm-,house1 at ,kew ,botanical ,gardens1 where it was desired to obstruct the passage of those rays which have a particular scorching influence4 ,of this glass a description was given at the meeting of the ,british ,association at ,oxford1 which appears in the ,transactions for that year4 ,the result has been all that could be desired--not a single instance of scorching having occurred during the three years which have elapsed4 #de ,in the ,philosophical ,transactions1 vol4 xc41 the following papers1 by ,sir ,william ,herschel1 may be consulted3-- ,investigation of the powers of the prismatic colours to heat and illuminate objects2 with remarks that prove the different refrangibility of radiant heat4 ,to which is added1 an inquiry into the method of viewing the sun advantageously1 with telescopes of large apertures and high magnifying powers1 p4 #bee4 ,experiments on the refrangibility of the invisible rays of the sun1 p4 #bhd4 ,experiments on the solar and on the terrestrial rays that occasion heat2 with a comparative view of the laws to which light and heat1 or rather the rays which occasion them1 are subject2 in order to determine whether they are the same or different1 pp4 #bic1 #dcg4 ,in connection with this inquiry1 ,sir ,william ,herschel remarks1 that since a red glass stops no less than #fib out of #a1jjj such rays as are of the refrangibility of red light1 we have a direct and simple proof1 in the case of the red glass1 that the rays of light are transmitted1 while those of heat are stopped1 and that thus they have nothing in common but a certain equal degree of refrangibility1 which by the power of the glass must occasion them to be thrown together into the place which is pointed out to us by the visibility of the rays of light4 ,on the same subject1 a ,memoir1 by ,sir ,henry ,englefield1 in the ,journal of the ,royal ,institution for #ahjb1 p4 #bjb1 may be consulted2 and ,researches on ,light1 by the ,author4 #df ,dr4 ,draper1 ,on the production of light by heat1 in the ,phil4 ,mag4 for #ahdg4 ,sir ,isaac ,newton fixed the temperature at which bodies become self-luminous at #fce2 ,sir ,humphry ,davy at #hab2 ,mr4 ,wedgewood at #idg2 and ,mr4 ,daniell at #ihj2 whilst ,dr4 ,draper from his experiments gives #igg2 and ,dr4 ,robinson #hfe4 ,in a review of the above paper by ,melloni1 entitled ,researches on the ,radiations of ,incandescent ,bodies1 and on the ,elementary ,colours of the ,solar ,spectrum1 translated for ,silliman's ,journal for ,august1 #ahdg1 he remarks3-- 8,i say that they conduct1 as do others heretofore known on light and radiant heat1 to a perfect analogy between the general laws which govern these two great agents of nature4 ,i will add that ,i regard the theory of their identity as the only one admissible by the rules of philosophy2 and that ,i consider myself obliged to adopt it1 until it shall have been proved to me that there is a necessity of having recourse to two different principles1 for the explanation of a series of phenomena which at present appear to belong to a solitary agent40 ,reference should also be made to a paper by ,dr4 ,robinson1 ,on the effects of ,heat in lessening the ,affinities of the ,elements of ,water1 in the ,transactions of the ,royal ,irish ,academy1 #ahdh1 where he says that 8when a platinum wire is traversed by a current gradually increased till it produces ignition1 the first gleam that appears is not red1 but of a colour which1 when ,i first saw it1 ,i compared to the #8lavender ray' discovered by ,sir ,john ,herschel beyond the violet1 though ,i was surprised at seeing the tint of that most refrangible ray preceding the ray which is least so4 ,it is quite conspicuous at about #hfe2 and as the mode in which it makes its appearance presents nothing abrupt or discontinuous1 it seems likely that it is merely a transition from invisible rays excited at a lower temperature to ordinary light40--p4 #caj4 #dg ,in the ,bakerian ,lecture for #ahdb1 ,on the transparency of the ,atmosphere1 and the law of extinction of the solar rays in passing through it1 by ,james ,d4 ,forbes1 ,esq41 ,f4,r4,s41 c41 will be found a most complete investigation of this subject4 ,the experiments were1 for the most part1 made in ,switzerland with ,sir ,john ,herschel's actinometer1 and they prove satisfactorily1--8,that the absorption of the solar rays by the strata of air to which we have immediate access1 is considerable in amount for even moderate thicknesses40 #dh ,after referring to several curious and instructive experiments1 in which peculiar chemical changes are produced under the influence of the solar rays by their ,,heat1 ,sir ,john ,herschel says3-- 8,these rays are distinguished from those of ,light by being invisible2 they are also distinguished from the pure calorific rays beyond the spectrum1 by their possessing properties 7of a peculiar character1 referred to in former papers7 either exclusively of the calorific rays1 or in a much higher degree4 ,they may perhaps not improperly be regarded as bearing the same relation to the calorific spectrum which the photographic rays do to the luminous ones4 ,if the restriction to these rays of the term thermic1 as distinct from calorific1 be not 7as ,i think1 in fact1 it is not7 a sufficient distinction1 ,i would propose the term parathermic rays to designate them4 ,these are the rays which ,i conceive to be active in producing those singular molecular affections which determine the precipitation of vapours in the experiments of ,messrs4 ,draper1 ,moser1 and ,hunt1 and which will probably lead to important discoveries as to the intimate nature of those forces resident on the surfaces of bodies1 to which ,m4 ,dutrochet has given the name of epipolic forces40--,on certain improvements in ,photographic ,processes1 described in a former communication 7,phil4 ,trans1 vol4 cxxxiii472 and ,on the ,parathermic ,rays of the ,solar ,spectrum1 ,phil4 ,trans1 vol4 cxxxiv4 ,the experiments of ,mrs4 ,somerville1 ,on the ,action of the ,rays of the ,spectrum on ,vegetable ,juices 7,phil4 ,transactions1 vol4 cxxxvii471 appear to connect themselves with this particular class of rays in a curious manner4 #di ,experiments on the influence of heat on differently-coloured bodies were first made by ,dr4 ,hooke2 and it was not until long after that ,franklin made his ingenious experiments4 ,davy exposed to sunshine six equal pieces of copper1 painted white1 yellow1 red1 green1 blue1 and black1 in such a manner that one side only was illuminated4 ,to the dark side he attached a bit of cerate1 ascertained by experiment to melt at #gjj4 ,the cerate attached to the black became fluid first1 the blue next1 then the green and red1 and lastly the yellow and white4--,beddoes's ,contributions to ,physical ,knowledge1 and collected works of ,sir ,humphry ,davy1 vol4 ii4 p4 #bg4 #ej ,by reference to the ,treatise on ,heat1 in the ,encyclopdia ,metropolitana1 numerous suggestive experiments will be found1 all bearing on this subject4 ,peschel's ,elements of ,physics may also be consulted with advantage4 ,the fact is1 however1 simply proved1 as stated in the text1 by placing the bulbs of delicate thermometers1 so as to be completely involved in the petals of flowers exposed to sunshine1 shading the upper portion of the stem of the instrument4 #ea ,moser1 ,on ,vision1 and on the ,action of ,light on ,bodies3 and also ,on ,latent ,light3 ,scientific ,memoirs1 vol4 iii4 ,draper1 ,on certain ,spectral ,appearances1 and on the ,discovery of ,latent ,light3 ,phil4 ,mag41 ,nov4 #ahdb4 #eb ,a particular examination of this curious question will be found in the ,author's report ,on the ,influence of the ,solar ,rays on the ,growth of ,plants3 ,reports of the ,british ,association for #ahdg4 #ec ,ammianus ,marcellinus ascribes the longevity and robust health of mountaineers to their exposure to the dews of night4 ,dew was employed by the alchemists in their experiments on the solution of gold4 ,the ladies of old collected the 8celestial wash10 which they imagined had the virtue of preserving their fine forms1 by exposing heaps of wool to the influences of night radiation4 ,it was supposed that the lean features of the grasshopper arose from that insect feeding entirely on dew3 8,dumque thymo pascentur apes1 dum rore cicad10 ,virgil1 ,eclog4 ,see some curious remarks by ,boyle1 ,on the ,power of ,dew in ,working on ,solid ,bodies3 ,works of the ,honourable ,r4 ,boyle1 vol4 v4 p4 #aba4 #agdd4 #ed ,see the ,researches on ,heat1 by ,professor ,james ,forbes1 in the ,transactions of the ,royal ,society of ,edinburgh2 also ,melloni's papers on the same subject in the ,annales de ,chimie1 several of which have been translated into the ,scientific ,memoirs1 edited by ,mr4 ,richard ,taylor4 #ee ,the phenomena of dew have constantly engaged the attention of man4 ,aristotle1 in his book ,de ,mundo1 puts forth some just notions on its nature4 ,an opinion has almost always prevailed that dew falls4 ,gersten appears to have been the first who opposed this motion4 ,he was followed by ,musschenbroek1 and then by ,du ,fay4 ,the researches of ,leslie were of a far more exact character4 ,dr4 ,wilson1 in the ,transactions of the ,royal ,society of ,edinburgh1 #ast vol41 published a ,memoir on ,hoar ,frost of much interest2 but the questions involved remained unsettled until the researches of ,dr4 ,wells1 which were published in his ,essay on ,dew4 #ef ,by far the most complete set of experiments on the radiation of heat from the surface at night1 which have been published since ,dr4 ,wells's memoir ,on ,dew1 are those of ,mr4 ,glaisher1 of the ,royal ,observatory at ,greenwich4 ,instruments of the most perfect kind were employed1 and the observations made with sedulous care4 ,the results will be found in a memoir ,on the ,amount of the ,radiation of ,heat1 at night1 from the ,earth1 and from various bodies placed on or near the ,surface of the ,earth1 by ,james ,glaisher1 ,esq41 ,philosophical ,trans4 for #ahdg1 part #b4 #eg ,dr4 ,wells noticed the practical fact that very light shades protected delicate plants from frost1 by preventing radiation4 ,mr4 ,goldsworthy ,gurney has made a series of interesting experiments1 and he imagines that by shading grasslands with boughs of trees1 or any light litter1 a more abundant crop is produced4 ,the subject has been discussed in the journals of the ,royal ,agricultural ,society4 ,may not the apparent increase be due entirely to the succulent condition in which a plant always grows in the shade8 #eh ,this paper of ,melloni's will be found in the ,bibliothque ,universelle de ,genve1 for #ahdc4 ,the conclusions are highly ingenious1 but they rest entirely on the analogy supposed to be discovered between the relations of heat1 like light1 to the coloured rays of the spectrum4 ,this1 it must be remembered1 is not the case1 since even ,sir ,william ,herschel showed that red light might exist with only a minimum of calorific power1 notwithstanding the fact1 that the maximum heat-ray of the spectrum coincides with the red rays4 #ei ,dr4 ,robinson1 of ,armagh1 in his ,memoir ,on the ,effects of ,heat in lessening the ,affinities of the ,elements of ,water4--,transactions of the ,royal ,irish ,academy1 vol4 xxi4 part #b4 #fj ,on this subject consult ,robert ,were ,fox1 ,on the ,temperature of the ,mines of ,cornwall4--,cornwall ,geological ,transactions1 vol4 ii42 ,w4 ,j4 ,henwood1 on the same subject1 ,ib4 vol4 v42 ,reports of the ,british ,association1 #ahdj1 p4 #cae2 ,edinburgh ,new ,philosophical ,journal1 vol4 xxiv4 p4 #adj4 #fa ,on the causes of the temperature of ,hot and ,thermal ,springs2 and on the bearings of this subject as connected with the general question regarding the internal temperature of the ,earth3 by ,professor ,gustav ,bischoff1 of ,bonn4--,edinburgh ,new ,philosophical ,journal1 vol4 xx4 p4 #cgf2 vol4 xxiii4 p4 #ccj4 ,some interesting information on the temperature of the ground will be found in ,erman's ,travels in ,siberia1 translated by ,w4 ,d4 ,cooley1 vol4 i4 p4 #cci2 vol4 ii4 p4 #cff4 ,sur la ,profondeur laquelle se trouve la couche de ,temprature invariable entre les ,tropiques1 by ,boussingault3 ,annales de ,chimie et de ,physique1 #ahcc1 p4 #bbe4 ,reference may also be made to ,humboldt's ,cosmos1 ,otto's translation2 and to the excellent article on ,meteorology1 by ,george ,harvey1 in the ,encyclopdia ,metropolitana4 ,these chthonisothermal lines1 as they are called1 have been traced by ,humboldt and others over extensive districts4 #fb ,these results are obtained from the valuable observations of ,robert ,were ,fox1 ,esq41 made with great care by that gentleman in several of the ,cornish mines3 ,report on some observations on ,subterranean ,temperature4--,british ,association ,reports1 vol4 ix4 p4 #cji2 ,philosophical ,magazine1 #ahcg1 vol4 ii4 p4 #ebj4 #fc ,from his experiments1 the following conclusions were arrived at by ,m4 ,delaroche3-- #a4 ,invisible radiant heat may1 in some circumstances1 pass directly through glass4 #b4 ,the quantity of radiant heat which passes directly through glass is so much greater1 relative to the whole heat emitted in the same direction1 as the temperature of the source of heat is more elevated4 #c4 ,the calorific rays which have already passed through a screen of glass1 experience1 in passing through a second glass screen of a similar nature1 a much smaller diminution of their intensity than they did in passing through the first screen4 #d4 ,the rays emitted by a hot body differ from each other in their faculty to pass through glass4 #e4 ,a thick glass1 though as much or more permeable to light than a thin glass of worse quality1 allows a much smaller quantity of radiant heat to pass4 ,the difference is so much the less as the temperature of the radiating source is more elevated4 #f4 ,the quantity of heat which a hot body yields in a given time1 by radiation to a cold body situate at a distance1 increases1 cteris paribus1 in a greater ratio than the excess of temperature of the first body above the second4--,journal de ,physique1 vol4 lxxv4 #fd ,sir ,david ,brewster differs from the conclusions arrived at by ,delaroche4 ,he thus explains his views3--8,the inability of radiant heat to pass through glass1 may be considered as a consequence of its refusing to yield to the refractive force2 for we can scarcely conceive a particle of radiant matter freely permeating a solid body1 without suffering some change in its velocity and direction4 ,the ingenious experiments of ,m4 ,prvost1 of ,geneva1 and the more recent ones of ,m4 ,delaroche1 have been considered as establishing the permeability of glass to radiant heat4 ,m4 ,prvost employed moveable screens of glass1 and renewed them continually1 in order that the result which he obtained might not be ascribed to the heating of the screen2 but such is the rapidity with which heat is propagated through a thin plate of glass1 that it is extremely difficult1 if not impossible1 to observe the state of the thermometer before it has been affected by the secondary radiation from the screen4 ,the method employed by ,m4 ,delaroche1 of observing the difference of effect1 when a blackened glass screen and a transparent one were made successively to intercept the radiant heat1 is liable to an obvious error4 ,the radiant heat would find a quicker passage through the transparent screen2 and1 therefore1 the difference of effect was not due to the transmitted heat1 but to the heat radiated from the anterior surface4 ,the truth contained in ,m4 ,delaroche's fifth proposition is almost a demonstration of the fallacy of all those that precede it4 ,he found that #8a thick plate of glass1 though as much or more permeable to light than a thin glass of worse quality1 allowed a much smaller quantity of radiant heat to pass4' ,if he had employed very thick plates of the purest flint glass1 or thick masses of fluid that have the power of transmitting light copiously1 he would have found that not a single particle of heat was capable of passing directly through transparent media40--,sir ,d4 ,brewster1 ,on new properties of heat as exhibited in its propagation along plates of glass4 ,philosophical ,transactions1 vol4 cvi4 p4 #ajg4 #fe ,proposal of a ,new ,nomenclature for the ,science of ,calorific ,radiations1 by ,m4 ,melloni4 ,bibliothque ,universelle de ,genve1 ,no4 #gj4 ,scientific ,memoirs1 vol4 iii4 part #ab4 ,many of the terms1 as ,diathermasy1 or transparency for heat2 ,adiathermasy1 opacity for heat2 ,thermochroic1 coloured for heat1 and others1 are valuable suggestions of forms of expression which are required in dealing with these physical phenomena4 #ff ,for a careful examination of the several theories of heat consult ,dr4 ,young's ,course of ,lectures on ,natural ,philosophy1 c41 ,lecture #eb1 ,on the ,measures and the ,nature of ,heat2 also ,powell's very excellent ,reports on ,radiant ,heat--,reports of the ,british ,association1 #ahcb1 #ahdj4 ,the transcendental view which the immaterial theory leads to1 cannot be better exemplified than by the following quotation from that inexplicable dream of a talented man1 ,elements of ,physiophilosophy1 by ,lorenz ,oken1 ,m4,d4 7translated for the ,ray ,society1 by ,alfred ,tulk73-- 8,heat is not matter itself any more than light is2 but it is only the act of motion in the primary matter4 ,in heat1 as well as in light1 there certainly resides a material substratum2 yet1 this substratum does not give out heat and light2 but the motion only of the substratum gives out heat1 and the tension only of the substratum light4 ,there is no body of heat2 nitrogen is the body of heat1 just as oxygen may be called the body of fire4 ,heat is real space2 into it all forms have been resolved1 as all materiality has been resolved into gravity1 and all activity1 all polarity1 into light4 ,heat is the universal form1 consequently the want of form40 #fg ,mmoires de la ,socit ,physique1 c41 de ,genve1 tom4 ii4 art4 #b4 #fh ,this curious phenomenon was first observed by ,mr4 ,trevelyan1 whose ,notice regarding some ,experiments on the ,vibration of ,heated ,metals will be found in the ,transactions of the ,royal ,society of ,edinburgh1 vol4 xii41 #ahcg4 ,in a ,memoir in the same volume1 entitled ,experimental ,researches regarding certain vibrations which take place between metallic masses having different temperatures1 ,professor ,forbes draws the following conclusions3-- #a4 8,the vibrations never take place between substances of the same nature4 #b4 8,both substances must be metallic4 7,this is now proved not to be necessary47 #c4 8,the vibrations take place with an intensity proportional 7within certain limits7 to the difference of the conducting powers of the metals for heat or electricity2 the metal having the least conducting power being necessarily the coldest4 #d4 8,the time of contact of two points of the metals must be longer than that of the intermediate portions4 #e4 8,the impulse is received by a distinct and separate process at each contact of the bar and block1 and in no case is the metallic connection of the bearing points in the bar1 or those of the block1 in any way essential4 #f4 8,the intensity of the vibration is 7under certain exceptions7 proportional to the difference of temperature of the metals40--,transactions of the ,royal ,society of ,edinburgh1 vol4 xii4 #fi ,the ,bakerian ,lecture4 ,on certain ,phenomena of ,voltaic ,ignition1 and the ,decomposition of ,water into its ,constituent ,gases by ,heat3 by ,w4 ,r4 ,grove1 ,esq4--,philosophical ,transactions1 #ahdg4 ,part #a4 #gj ,davy's ,researches on ,flame4 ,works1 vol4 vi4--,philosophical ,transactions for #ahag4 #ga ,on the ,effect of ,heat in lessening the affinities of the ,elements of ,water3 by the ,rev4 ,thomas ,romney ,robinson1 ,d4,d4--,transactions of the ,royal ,irish ,academy1 vol4 xxi4 part #b4 #gb ,an ,inquiry concerning the ,chemical ,properties that have been attributed to ,light3 by ,benjamin1 ,count of ,rumford4--,philosophical ,transactions1 vol4 lxxxviii4 p4 #ddi4--,the results obtained by ,count ,rumford were probably due to the non-luminous heat-rays--parathermic rays--which are known to be given off by boiling water4 #gc ,for ,dr4 ,drapers paper1 see ,philosophical ,magazine for ,may1 #ahdg1 vol4 xxx4 #crd series4 #gd ,on the ,action of the ,rays of the ,solar ,spectrum on ,vegetable ,colours3 by ,sir ,j4 ,f4 ,w4 ,herschel1 ,bart4 ,the proof of the continuation of the visible prismatic spectrum beyond the extreme violet may be witnessed in the following manner3--8,paper stained with tincture of turmeric is of a yellow colour2 and1 in consequence1 the spectrum thrown in it1 if exposed in open daylight1 is considerably affected in its apparent colours1 the blue portion appearing violet1 and the violet very pale and faint2 but beyond the region occupied by the violet rays1 is distinctly to be seen a faint prolongation of the spectrum1 terminated laterally1 like the rest of it1 by straight and sharp outlines1 and which1 in this case1 affects the eye with the sensation of a pale yellow colour40--,philosophical ,transactions1 p4 #acc4 #ge ,the most complete exposition of the theory that animal heat is derived from chemical action only1 will be found in ,animal ,chemistry1 or ,chemistry in its applications to ,physiology and ,pathology1 by ,justus ,liebig3 translated by ,dr4 ,gregory4 ,the conclusions arrived at by the author1 notwithstanding his high--and deservedly high--position in chemical science1 must1 however1 be received with great caution1 many of them being founded on most incorrect premises1 and his generalizations being of the most hasty and imperfect character4 ,at page #bb the following passage occurs3--8,if we were to go naked1 like certain savage tribes1 or if in hunting or fishing we were exposed to the same degree of cold as the ,samoiedes1 we should be able1 with ease1 to consume ten pounds of flesh1 and1 perhaps1 a dozen of tallow candles into the bargain1 daily1 as warmly clad travellers have related with astonishment of these people4 ,we should then also be able to take the same quantity of brandy or train-oil without bad effects1 because the carbon and hydrogen of these substances would only suffice to keep up the equilibrium between the external temperature and that of our bodies40 ,a brief examination will exhibit the error of this4 ,the analysis of ,beef1 by ,d4 ,lyon ,playfair1 is as follows3-- ,carbon #eahc ,hydrogen #geg ,nitrogen #aeja ,oxygen #bacg ,ashes #dbc ,and the following has been given by ,chevreul as the composition of mutton tallow3-- ,carbon #if ,hydrogen #af ,nitrogen #af ,oxygen #dh ,about three times the quantity of oxygen to the carbon eaten1 is required to convert it into carbonic acid2 hence1 the ,samoiede1 eating more highly carbonized matter1 must inspire #bhh oz4 of oxygen daily1 or nearly eight times as much as the 8ordinary adult40 ,by the lungs he must take into the body #b1cjd cubic feet of air besides what will be absorbed by the skin4 ,his respirations must be so much quickened1 that at the lowest possible calculation he must have #ejj pulsations a minute4 ,under such conditions it is quite clear man could not exist4 ,there is no disputing the fact of the enormous appetites of these people2 but all the food is not removed from the system as carbonic acid gas4 #gf ,an interesting paper by ,dr4 ,davy1 ,on the ,temperature of ,man1 will be found in the ,philosophical ,transactions1 vol4 cxxxvi4 p4 #cai4--,sir ,humphry ,davy1 in his ,consolations in ,travel1 or the ,last ,days of a ,philosopher1 in his fourth dialogue1 ,the ,proteus1 has several ingenious speculations on this subject4 #gg ,expos de quelques rsultats obtenus par l'action combine de la chaleur et de la compression sur certains liquides1 tels que l'eau1 l'alcool1 l'ther sulfurique1 et l'essence de ptrole rectifie3 par ,m4 le ,baron ,cagniard de la ,tour4 ,the three following conclusions are arrived at3-- #a4 ,que l'alcool #cf degrs1 l'essence de ptrole rectifie #db degrs1 et l'ther sulfurique soumis l'action de la chaleur et de la compression1 sont susceptibles de se rduire compltement en vapeur sous un volume un peu plus que double de celui de chaque liquide4 #b4 ,qu'une augmentation de pression1 occasionne par la prsence de l'air dans plusieurs des experiences qui viennent d'tre cites1 n'a point apport d'obstacle l'vaporation du liquide dans le mme espace2 qu'elle a seulement rendu sa dilatation plus calme et plus facile suivre jusqu'au moment o le liquide semble s'vanouir tout--coup4 #c4 ,que l'eau1 quoique susceptible sans doute d'tre rduite en vapeur trs-comprime1 n'a pu tre soumise des experiences compltes1 faute de moyens suffisans pour assurer l'exacte fermeture de la marmite de compression1 non plus que dans les tubes de verre dont elle altre la transparence en s'emparant de l'alcali qui entre dans leur composition4--,annales de ,chimie1 vol4 xxi4 #gh ,sur les phnomnes qui prsentent les corps projets sur des surfaces chaudes3 par ,m4 ,boutigny 7d',evreux74--,annales de ,chimie et de ,physique1 vol4 xi4 p4 #af4 ,conglation du mercure en trois secondes1 en vertu de l'tat sphrodal dans un creuset incandescent3 by ,m4 ,faraday4--,ibid41 vol4 xix4 p4 #chc4 ,spheroidal ,condition of ,bodies 7,extrait d'une ,note de ,m4 ,boutigny d',evreux74 8,au nombre des proprits des corps l'tat sphrodal1 il en est cinq qui me paraissent caractristiques et fondamentales1 et c'est sur ces cinq proprits que je base la dfinition que je soumets aujourd'hui au jugement de l',acadmie4 ,ces cinq proprits sont3-- 8#a4 ,la forme arrondie que prend la matire sur une surface chauffe une certaine temprature4 8#b4 ,le fait de la distance permanente qui existe entre le corps l'tat sphrodal et le corps sphrodalisant4 8#c4 ,la proprit de rflchir le calorique rayonnant4 8#d4 ,la suspension de l'action chimique4 8#e4 ,la fixit de la temprature des corps l'tat sphrodal4 8,cela pos1 voici la dfinition que je propose3 un corps projet sur une surface chaude est l'tat sphrodal quand il revt la forme arrondie et qu'il se maintient sur cette surface au del du rayon de sa sphre d'activit physique et chimique2 alors il rflchit le calorique rayonnant1 et ses molcules sont1 quant la chaleur1 dans un tat d'quilibre stable2 c'est--dire1 une temprature invariable1 ou qui ne varie que dans des limites troites40--,comptes ,rendus1 #f ,mars1 #ahdh4 #gi ,some ,facts relative to the ,spheroidal ,state of ,bodies1 ,fire ,ordeal1 ,incombustible ,man1 c43 by ,p4 ,h4 ,boutigny 7d',evreux71 ,philosophical ,magazine1 ,no4 #bcc 7third1 series71 p4 #hj2 ,comptes ,rendus1 ,may #ad1 #ahdi4 #hj ,the theory of freezing mixtures is deduced from the doctrine of latent caloric4 ,these are mixtures of saline substances which1 at the common temperature1 by their mutual chemical action1 pass rapidly into the fluid form1 or are capable of being rapidly dissolved in water1 and1 by this quick transition to fluidity1 absorb caloric1 and produce degrees of cold more or less intense4--,rev4 ,francis ,lunn1 ,on ,heat3 ,encyclopdia ,metropolitana4 #ha ,proprits de l',acide ,carbonique liquide1 par ,m4 ,thilorier1 ,annales de ,chimie1 vol4 lx4 p4 #dbg4 ,solidification de l',acide ,carbonique3 ,ibid4 p4 #dcb4 #hb ,on the ,liquefaction and ,solidification of ,bodies generally existing as ,gases1 by ,michael ,faraday1 ,d4,c4,l41 ,f4,r4,s41 c42 ,philosophical ,transactions1 vol4 cxxxvi1 p4 #aee4 #hc ,burns1 in one of his most natural and pathetic letters4 ,,chapter ,,vii4 ,,light4 ,theories of the ,nature of ,light--,hypotheses of ,newton and ,huygens--,sources of ,light--,the ,sun--,velocity of ,light--,transparency--,dark ,lines of the ,spectrum--,absorption of ,light--,colour--,prismatic ,analysis--,rays of the ,spectrum--,rainbow--,diffraction--,inte rference--,goethe's ,theory--,polarisation--,magnetisation of ,light--,vision--,the ,eye--,analogy--,sound and ,light--,influence of ,light on ,animals and ,vegetables--,phosphorescence arising from several ,causes--,artificial ,light--,its ,colour dependent on ,matter4 ,light1 the first creation1 presents to the enquiring mind a series of phenomena of the most exalted character4 ,the glowing sunshine1 painting the earth with all the brilliancy of colour1 and giving to the landscape the inimitable charm of every degree of illumination1 from the grey shadow to the golden glow2--the calm of evening1 when1 weary of the 8excess of splendour10 the eye can repose in tranquillity upon the 8cloud-land0 of the west1 and watch the golden and the ruddy hues fade slowly into the blue tincture of night2--and the pale refulgence of the moon1 with the quiet sparkle of the sun-lit stars1--all tend to impress upon the soul1 the great truth that1 where there is light1 organisation and life are found1 and beyond its influence death and silence hold supreme dominion4#hd ,through all time we have evidences that this has been the prevailing feeling of the human race1 derived1 of course1 from their observation of the natural phenomena dependent upon luminous agency4 ,in the myths of every country1 impersonations of light prevail1 and to these are referred the mysteries of the perpetual renewal of life on the surface of the earth4 ,this presentiment of a philosophic truth1 in the instance of the poet sages of intellectual ,greece1 was advanced to the highest degree of refinement2 and the sublime exclamation of ,plato3 8,light is truth1 and ,god is light10 approaches nearly to a divine revelation4 ,as the medium of vision--as the cause of colour--as a power influencing in a most striking manner all the forms of organisation around us1 light presented to the inquiring minds of all ages a subject of the highest interest4 ,the ancient philosophers1 although they lost themselves in the metaphysical subtleties of their schools1 could not but discover in light an element of the utmost importance in natural operations4 ,the alchemists regarded the luminous principle as a most subtile fluid1 capable of interpenetrating and mingling with gross matter3 gold being supposed to differ from the baser metals only in containing a larger quantity of this ethereal essence4#he ,modern science1 after investigating most attentively a greater number of the phenomena of light1 has endeavoured to assist the inquiry by the aid of hypotheses4 ,newton1 in a theory1 which exhibits the refined character of that great philosopher's mind1 supposes luminous particles to dart from the surfaces of bodies in all directions--that these infinitely minute particles are influenced by the attracting and repelling forces of matter1 and thus turned back1 or reflected1 from their superficies in some cases1 and absorbed into their interstitial spaces in others4 ,huyghens1 on the contrary1 supposes light to be caused by the waves or vibrations of an infinitely elastic medium--,,ether--diffused through all space1 which waves are propagated in every direction from the luminous body4 ,in the first theory1 a luminous particle is supposed actually to come from the sun to the earth2 in the other1 the sun only occasions a disturbance of the ether1 which extends with great rapidity1 in the same manner as a wave spreads itself over the surface of a lake4 ,nearly all the facts known in the time of ,newton1 and those discovered by him1 were explained most satisfactorily by his hypothesis2 but it was found they could be interpreted equally as the effects of undulation1 with the exception of the production of colour by prismatic refraction4 ,although the labours of many gifted minds have been given1 with the utmost devotion1 to the support of the vibratory theory1 this simple fact has never yet received any satisfactory explanation2 and there are numerous discoveries connected with the molecular and chemical disturbances produced by the sun's rays1 which do not appear to be explained by the hypothesis of emission or of undulation4 ,in both theories a wave motion is admitted1 and every fact renders it probable that this mode of progression applies not only to light1 but to the so-called imponderable forces in general4 ,admitting1 therefore1 the undulatory movement of luminous rays1 we shall not stop to consider those points of the discussion which have been so ably dealt with by ,young1 ,laplace1 ,fresnel1 ,biot1 ,fraunhofer1 ,herschel1 ,brewster1 and others1 but proceed at once to consider the sources of light1 and its more remarkable phenomena4#hf ,the sun is the greatest permanently luminous body we are acquainted with1 and that orb is continually pouring off light from its surface in all directions at the rate1 through the resisting medium of space and of our own atmosphere1 of #aib1jjj miles in a second of time4 ,it has been calculated1 however1 that light would move through a vacuum with the speed of #aib1ejj miles in the same period4 ,we1 therefore1 learn that a ray of light requires eight minutes and thirteen seconds to come from the sun to us4 ,in travelling from the distant planet ,uranus1 nearly three hours are exhausted2 and from the nearest of the fixed stars each ray of light requires more than six years to traverse the intervening space between it and the earth4 ,allow the mind to advance to the regions of nebul1 and it will be found that hundreds of years must glide away during the passage of their radiations4 ,consequently1 if one of those masses of matter1 or even one of the remote fixed stars1 was 8blotted out of heaven0 to-day1 several generations of the finite inhabitants of this world would fade out of time before the obliteration could be known to man4 ,here the immensity of space assists us in our conception1 limited though it be1 of the for-ever of eternity4#hg ,all the planets of our system shine with reflected light1 and the moon1 our satellite1 also owes her silvery lustre to the sun's radiations4 ,the fixed stars are1 in all probability1 suns shining from the far distance of space1 with their own self-emitted lights4 ,by the photometric researches of ,dr4 ,wollaston1 we learn1 however1 that it would take #bj1jjj millions of such orbs as ,sirius1 the brightest of the fixed stars1 to afford as much light as we derive from the sun4 ,the same observer has proved that the brightest effulgence of the full moon is yet #hja1jgb times less than the luminous power of our solar centre4 ,the cultivators of modern science are a bold race2 not contented with endeavouring to understand the physical earth1 they are endeavouring to comprehend the condition of the solar surface4 ,the mind of man can penetrate far into nature1 and1 as it were1 feel out the mysteries of untraversed space4 ,the astronomer learns of a peculiar condition of light1 which is termed polarisation1 and he learns by this1 too1 that he can determine if from a bright luminous disc the light is derived from a solid mass in a state of intense ignition1 or from vapour in an incandescent condition4 ,he adds a polarising apparatus to his telescopes1 and he determines that the light we derive from the sun is due to an envelope of vapour--burning1 in all probability--only with greater intensity1 as the gas which we now employ4 ,this ,photosphere--as it has been called by the late ,french philosopher ,arago1 is found to be subjected to violent disturbances1 and the dark spots seen on the sun's disc are now known to be openings through this mysterious envelope of light1 which enable us to look in upon the dark body of the sun itself4 ,luminous phenomena may be produced by various means--chemical action is a source of light2 and1 under several circumstances in which the laws of affinity are strongly exerted1 a very intense luminous effect is produced4 ,under this head all the phenomena of combustion are included4 ,in the electric spark we have the development of light2 and the arc which is formed between charcoal points at the poles of a powerful voltaic battery affords us the most intense artificial illumination with which we are acquainted4 ,in addition to these1 we have the peculiar phenomena of phosphorescence arising from chemical1 calorific1 electrical1 actinic1 and vital excitation1 all of which must be particularly examined4 ,from whatever source we procure light1 it is the same in character1 differing only in intensity4 ,in its action upon matter1 we have the phenomena of transmission1 of reflection1 of refraction1 of colour1 of polarisation1 and of vision1 to engage our attention4 ,a beam of white light falls upon a plate of colourless glass1 and it passes freely through it1 losing but little of its intensity2 the largest portion being lost by reflection from the first surface upon which the light impinges4 ,if the glass is roughened by grinding1 we lose more light by absorption and by reflection from the asperities of the roughened surface2 but if we cover that face with any oleaginous fluid1 as1 for instance1 turpentine1 its transparency is restored4 ,we have thus direct proof that transparency to light is due to molecular condition4 ,this may be most strikingly shown by an interesting experiment of ,sir ,david ,brewster's3-- ,if a glass tube is filled with nitrous acid vapour1 which is of a dull red colour1 it admits freely the passage of the red and orange rays with some of the others1 and1 if held upright in the sunshine1 casts a red shadow on the ground2 by gently warming it with a spirit-lamp1 whilst in this position1 it acquires a much deeper and blacker colour1 and becomes almost impervious to any of the rays of light2 but upon cooling it again recovers its transparency4 ,it has also been stated by the same exact experimentalist1 that having brought a purple glass to a red heat1 its transparency was improved1 so that it transmitted green1 yellow1 and red rays1 which it previously absorbed2 but the glass recovered its absorptive powers as it cooled4 ,a piece of yellowish-green glass lost its transparency almost entirely by being heated4 ,native yellow orpiment becomes blood-red upon being warmed1 when nearly all but the red rays are absorbed2 and pure phosphorus1 which is of a pale yellow colour1 and transmits freely all the coloured rays upon being melted1 becomes very dark1 and transmits no light4 ,chemistry affords numerous examples of a very slight change of condition1 producing absolute opacity in fluids which were previously diaphanous4#hh ,charcoal absorbs all the light which falls upon it1 but in some of its states of combination1 and in the diamond1 which is pure carbon1 it is highly transparent4 ,gold and silver beaten into thin leaves are permeated by the green and blue rays1 and the metals in combination with acids are all of them more or less transparent4 ,what becomes of the light which falls upon and is absorbed by bodies1 is a question which we cannot yet1 notwithstanding the extensive observations that have been made by some of the most gifted of men1 answer satisfactorily4 ,in all probability1 as already stated1 it is permanently retained within their substances2 and many of the experiments of exciting light in bodies when in perfect darkness1 by the electric spark and other means1 appear to support the idea of light becoming latent or hidden4 ,no body is absolutely transparent2 some light is lost in passing even through ethereal space1 and still more in traversing our atmosphere4 ,amongst the most curious instances of absorption is that which is uniformly discovered in the solar spectrum1 particularly when we examine it with a telescope4 ,we then find that the coloured rays are crossed by a great number of dark bands or lines1 giving no light2 these are generally called ,fraunhofer's dark lines1 as it was to the indefatigable exertions of that experimentalist1 and by the aid of his beautiful instruments1 that most of them were discovered and measured1 and enumerated1 although they were previously noticed by ,dr4 ,wollaston4 ,it is quite clear that those lines represent rays which have been absorbed in their passage from the sun to the earth3 although some of them have no doubt undergone absorption within the limits of the earth's atmosphere1 we have every reason to believe1 with ,sir ,john ,herschel1 that the principal absorption takes place in the atmosphere of the sun4#hi ,it has been proved by ,dr4 ,miller1 that the number of those dark lines is continually varying with the alteration of atmospheric conditions2#ij and the evidences which have been afforded1 of peculiar states of absorption by the gaseous envelope of the earth1--during the prosecution of investigations on the chemical agencies of the sun's rays1--are of a sufficiently convincing character4 ,it has been calculated by ,bouguer1 that if our atmosphere1 in its purest state1 could be extended rather more than #gjj miles from the earth's surface instead of nearly #dj1 as it is at present1 the sun's rays could not penetrate it1 and this globe would roll on in darkness and silence1 without a vestige of vegetable form or of animal life4 ,in the ,hebrew version of the ,mosaic ,history1 the reading is1 8,let light appear30 may not this really mean that the earth's atmosphere was so cleared of obstructing vapours1 that the solar rays were enabled to reach the earth8 ,the same calculation supposes that sea-water loses all its transparency at the depth of #gcj feet2 but a dim twilight must prevail much deeper in the ocean4 ,the researches of ,professor ,edward ,forbes have proved1 that at the depth of #bcj fathoms in the gean sea1 the few shelled animals that exist are colourless3 no plants are found within that zone2 and that industrious naturalist fixes the zero of animal life of those waters at about #cjj fathoms4#ia ,since these zones mark the rapidly diminishing light1 it is evident that where life ceases to be must be beyond the limits to which life can penetrate4 ,our atmosphere1 charged with aqueous vapour1 serves to shield us from the intense action of the solar powers4 ,by it we are protected from the destructive influences of the sun's light and heat2 enjoy those modified conditions which are most conducive to the healthful being of organic forms2 to it we owe 8the blue sky bending over all10 and those beauties of morning and evening twilight of which ---- ,sound and motion own the potent sway4 ,responding to the charm with its own mystery4 ,to defective transparency1 or rather to the different degrees of it1 we must attribute1 in part1 the colours of permeable media4 ,thus1 a glass or fluid appears yellow to the eye1 because it has the property of admitting the permeation of a larger quantity of the yellow rays than of any others2--red1 because the red rays pass it with the greatest freedom2 and so on for every other colour4 ,in most cases the powers of transmission and of reflection are similar2 but it is not so in all2 a variety of fluor spar1 which1 while it transmits green light1 reflects blue1 and the precious opal1 are striking instances to the contrary4 ,some glasses1 which transmit yellow light have the singular power of dispersing blue rays from one surface2 and a solution of quinine in water acidulated with sulphuric acid1 although perfectly transparent and colourless when held between the eye and the light1 exhibits1 if viewed in a particular direction1 a lively cerulean tint4 ,these effects being supposed to be due to the conditions of the surface1 have been called epipolic phenomena4#ib ,the careful investigation of these phenomena has made us acquainted with some very interesting facts1 and indeed discovered to us a set of luminous rays which were previously unknown4 ,the dispersion of blue light from the surface of some yellow glasses--such as have been coloured by the oxide of silver--is of a different order from that which takes place with the solution of sulphate of quinine1 or with the fluor spar4 ,the first depends upon a peculiar condition of the surface1 while the latter phenomena are due to a dispersion which takes place within the solid or fluid4 ,in addition to the sulphate of quinine1 and the fluor spar1 we obtain the same results in a very marked manner by a canary yellow glass1 coloured with the oxide of uranium1 and by a decoction of the inner bark of the horse-chesnut tree4 ,mr4 ,stokes1 who has investigated this class of phenomena1 and proposes to call it ,fluorescence1 from its being naturally seen in fluor-spar1 has shown that the peculiar internal dispersion1 and the consequent alteration of the colour of the ray1 is due to an alteration in its refrangibility4 ,whether this hypothesis prove to be the correct one or not1 it is certain that there exists a set of rays of far higher refrangibility than those seen in the ordinary ,newtonian spectrum4 ,this may be shown in the following manner3 taking either of the solutions named1 or a block of uranium glass1 throw upon one face1 by means of a prism1 a very pure spectrum4 ,on looking into the glass or fluid there will be seen1 commencing amidst the most refrangible rays1 a new set of spectral rays1 struggling to make their way through the absorbent medium4 ,these are of a blue colour in the quinine or chesnut solution1 and green in the uranium glass1 and are seen extending themselves far beyond the most refrangible rays of the ordinary ,newtonian spectrum4 ,this is the space over which those rays which have the power of producing chemical changes1 such as are rendered familiar by the practice of ,photography1 are detected in their greatest activity4 ,it has1 therefore1 been supposed that these fluorescent rays are the chemical rays rendered luminous by the alteration of their refrangibility4 ,this view has received much support from the fact that the extra spectral rays are crossed with numerous dark lines1 and that in the chemical impressions these lines are marked by unchanged spaces which exactly coincide with them4 ,there is1 however1 much doubt of the correctness of this1 since1 in the uranium glass of such a thickness that these visible rays are quite absorbed1 the chemical rays still pass4 ,however1 the whole question requires1 and is receiving1 the most searching investigation4 ,the discovery of these phenomena1 which are included under the term of ,fluorescence1 is of that interesting and important character1 that it must be ranked as the most decided advance which has been made in physical optics since the days of ,newton4 ,it is not improbable that those rays of such high refrangibility may1 although they are under ordinary circumstances invisible to the human eye1 be adapted to produce the necessary degree of excitement upon which vision depends in the optic nerves of the night-roaming animals4 ,the bat1 the owl1 and the cat1 may see in the gloom of night by the aid of rays which are invisible to1 or inactive on the eyes of man1 or of those animals which require the light of day for perfect vision4 ,it is a general law of the radiant forces1 that whenever they fall upon any surface1 a portion is thrown back or reflected at the same time as other portions are absorbed or transmitted4 ,upon this peculiarity appear to depend the phenomena of natural colour in bodies4 ,the white light of the sun is well known to be composed of several coloured rays4 ,or rather1 according to the theory of undulations1 when the rate at which a ray vibrates is altered1 a different sensation is produced upon the optic nerve4 ,the analytical examination of this question shows1 that to produce a red colour the ray of light must give #cg1fdj undulations in an inch1 and #deh1jjjjjj1jjjjjj in a second4 ,yellow light requires #dd1jjj undulations in an inch1 and #ece1jjjjjj1jjjjjj in a second2 whilst the effect of blue results from #ea1aaj undulations within an inch1 and #fbb1jjjjjj1jjjjjj of waves in a second of time4#ic ,the determination of such points as these is among the highest refinements of science1 and1 when contrasted with the most sublime efforts of the imagination1 they must appear immeasurably superior4 ,if a body sends back white light unchanged1 it appears white2 if the surface has the property of altering the vibration to that degree which is calculated to produce redness1 the result is a red colour3 the annihilation of the undulations produces blackness4 ,by the other view1 or the corpuscular hypothesis1 the beam of white light is supposed to consist of certain coloured rays1 each of which has physical properties peculiar to itself1 and thus is capable of producing different physiological effects4 ,these rays falling upon a transparent or an opaque body suffer more or less absorption1 and being thus dissevered1 we have the effect of colour4 ,a red body absorbs all the rays but the red2 a blue surface1 all but the blue2 a yellow1 all but the yellow2 and a black surface absorbs the whole of the light which falls upon it4 ,that natural colours are the result of white light1 and not innate properties of the bodies themselves1 is most conclusively shown by placing coloured bodies in monochromatic light of another kind1 when they will appear either of the colour of that light1 or1 by absorbing it1 become black2 whereas1 when placed in light of their own character1 the intensity of colour is greatly increasing4 ,every surface has1 therefore1 a peculiar constitution1 by which it gives rise to the diversified hues of nature4 ,the rich and lively green1 which so abundantly overspreads the surface of the earth1 the varied colours of the flowers1 and the numberless tints of animals1 together with all those of the productions of the mineral kingdom1 and of the artificial combinations of chemical manufacture1 result from powers by which the relations of matter to light are rendered permanent1 until its physical conditions undergo some change4 ,there is a remarkable correspondence between the geographical position of a region and the colours of its plants and animals4 ,within the tropics1 where 8,the sun shines for ever unchangeably bright10 the darkest green prevails over the leaves of plants2 the flowers and fruits are tinctured with colours of the deepest dye1 whilst the plumage of the birds is of the most variegated description and of the richest hues4 ,in the people also of these climes there is manifested a desire for the most striking colours1 and their dresses have all a distinguishing character1 not of shape merely1 but of chromatic arrangement4 ,in the temperate climates everything is of a more subdued variety3 the flowers are less bright of hue2 the prevailing tint of the winged tribes is a russet brown2 and the dresses of the inhabitants of these regions are of a sombre character4 ,in the colder portions of the earth there is but little colour2 the flowers are generally white or yellow1 and the animals exhibit no other contrast than that which white and black afford4 ,a chromatic scale might be formed1 its maximum point being at the equator1 and its minimum at the poles4#id ,the influence of light on the colours of organized creation is well shown in the sea4 ,near the shores we find sea-weeds of the most beautiful hues1 particularly on the rocks which are left dry by the tides2 and the rich tints of the actini1 which inhabit shallow water1 must have been often observed4 ,the fishes which swim near the surface are also distinguished by the variety of their colours1 whereas those which live at greater depths are grey1 brown1 or black4 ,it has been found that after a certain depth1 where the quantity of light is so reduced that a mere twilight prevails1 the inhabitants of the ocean become nearly colourless4 ,that the sun's ray alone gives to plants the property of reflecting colour is proved by the process of blanching1 or etiolation1 produced by artificially excluding the light4 ,by a triangular piece of glass--a prism1--we are enabled to resolve light into its ultimate rays4 ,the white pencil of light which falls on the first surface of the prism is bent from its path1 and coloured bands of different colours are obtained4 ,these bands or rays observe a curious constancy in their positions3 the red ray is always the least bent out of the straight path3 the yellow class comes next in the order of refrangibility2 and the blue are the most diverted from the vertex of the prism4 ,the largest amount of illuminating power exists in the yellow ray1 and it diminishes towards either end4#ie ,it is not uninteresting to observe something like the same variety of colour occurring at each end of the prismatic spectrum4 ,the strict order in which the pure and mixed coloured rays present themselves is as follows3-- #a4 ,the extreme red3 a ray which can only be discovered when the eye is protected from the glare of the other rays by a cobalt blue glass1 is of a crimson character--a mixture of the red and the blue1 red predominating4#if #b4 ,the red3 the first ray visible under ordinary circumstances4 #c4 ,the orange3 red passing into and combining with yellow4 #d4 ,the yellow3 the most intensely luminous of the rays4 #e4 ,the green3 the yellow passing into and blending with the blue4 #f4 ,the blue3 in which the light very rapidly diminishes4 #g4 ,the indigo3 the dark intensity of blue4 #h4 ,the violet3 the blue mingled again with the red--blue being in excess4 #i4 ,the lavender grey3 a neutral tint1 produced by the combination of the red1 blue1 and yellow rays1 which is discovered most easily when the spectrum is thrown upon a sheet of turmeric paper4 #aj4 ,the fluorescent rays3 which are either a pure silvery blue or a delicate green4 ,newton regarded the spectrum as consisting of seven colours of definite and unvarying refrangibility4 ,brewster and others appear to have detected a great diffusion of the colours over the spectrum1 and regard white light as consisting only of three rays1 which in the prismatic images overlap each other2 and from these--red1 yellow1 and blue--all the others can be formed by combination in varying proportions4 ,the truth will probably be found to be1 that the ordinary prismatic spectrum is a compound of two spectra3--that is1 as we have the ordinary rainbow1 and a supplementary bow1 the colours of which are inverted1 so the extraordinary may be somewhat masked by the intense light of the ordinary spectrum2 and yet by overlapping produce the variations of colour in the rays4 ,we have already examined the heating power found in these coloured bands1 which1 although shown to be in a remarkable manner in constant agreement with the colour of a particular ray1 is not directly connected with it2 that is1 not as the effect of a cause1 or the contrary4 ,the chemical action of the solar rays1 to which from its important bearings we shall devote a separate chapter1 has1 in like manner with heat1 been confounded with the sun's luminous power2 but although associated with light and heat1 and modified by their presence1 it must be distinguished from them4 ,we find the maximum of heat at one end of the spectrum1 and that of chemical excitation at the other--luminous power observing a mean point between them4 ,without doubt we have these powers acting reciprocally1 modifying all the phenomena of each other1 and thus giving rise to the difficulties which beset the inquirer on every side4 ,we have beautiful natural illustrations of luminous refraction in the rainbow and in the halo3 in both cases the rays of light being separated by the refractive power of the falling rain drop1 or the vesicles which form the moisture constituting a fog4 ,in the simple toy of the child--the soap-bubble floating upon the air--the philosopher finds subjects for his contemplation2 and from the unrivalled play of colours which he discovers in that attenuated film1 he learns that the varying thicknesses of surfaces influence1 in a most remarkable manner1 the colours of the sunbeam4 ,films of oil floating upon water present similar appearances2 and the colours developed in tempering steel are due entirely to the thickness of the oxidized surface produced by heat4 ,there have lately been introduced some beautiful specimens of paper rendered richly iridescent by the following process3--,a solution of a gum resin in chloroform is floated upon water1 where it forms a film giving all the colours of ,newton's rings4 ,a sheet of paper which has been previously sunk in the water is carefully lifted1 and the film thus removed adheres with great firmness to the paper1 and produces this rich and curious play of colour4 ,the rich tints upon mother-of-pearl1 in the feathers of many birds1 the rings seen in the cracks of rock-crystal1 or between the unequal faces of two pieces of glass1 and produced by many chemical and indeed mechanical operations--are all owing to the same cause2--the refraction of the luminous pencil by the condition of the film or surface4 ,if we take one of those steel ornaments which are formed by being covered with an immense number of fine lines1 it will be evident that these stri present many different angles of reflection1 and that1 consequently1 the rays thrown back will1 at some point or another1 have a tendency to cross each other4 ,the result of this is1 that the quantity of light is augmented at some points of intersection1 and annihilated at others4#ig ,out of the investigation of the phenomena of diffraction1 of the effects of thin and thick plates upon light1 and the results of interference1 has arisen the discovery of one of the most remarkable conditions within the range of physical science4 ,two bright lights may be made to produce darkness4--,if two pencils of light radiate from two spots very close to each other in such a manner that they cross each other at a given point1 any object placed at that line of interference will be illuminated with the sum of the two luminous pencils4 ,if we suppose those rays to move in waves1 and the elevation of the wave to represent the maximum of luminous effect1 then the two waves meeting1 when they are both at the height of their undulation1 will necessarily produce a spot of greater intensity4 ,if now we so arrange the points of radiation1 that the systems of luminous waves proceed irregularly1 and that one arrives at the screen half an undulation before the other1 the one in elevation falling into the depression of the other1 a mutual annihilation is the consequence4 ,this fact1 paradoxical as it may appear1 was broadly stated by ,grimaldi1 in the description of his experiments on the inflection of light1 and has been observed by many others4 ,the vibratory hypothesis1 seizing upon the analogy presented by two systems of waves in water1 explains this plausibly1 and many similar phenomena of what is called the interference of light2 but still upon examination it does not appear that the explanation is quite free from objection4#ih ,another theory1 not altogether new to us1 it being indicated in ,mayer's hypothesis of three primary colours 7#agge71 and to be found as a problem in some of the ,encyclopdias of the last century1 has been put forth1 in a very original manner1 by that master-mind of intellectual ,germany1 ,goethe2 and from the very comprehensive views which this poet-philosopher has taken of both animal and vegetable physiology 7views which have been adopted by some of the first naturalists of ,europe71 we are bound to receive his theory of colours with every respect and attention4 ,goethe regards colour as the 8thinning0 of light2 for example1 by obstructing a portion of white light1 yellow is produced2 by reducing it still farther1 red is supposed to result2 and by yet farther retarding the free passage of the beam1 we procure a blue colour1 which is the next remove from blackness1 or the absence of light4 ,there is truth in this2 it bears about it a simplicity which will satisfy many minds2 by it many of the phenomena of colour may be explained3 but it is insufficient for any interpretation of several of those laws to which the other theories do give us some insight4 ,newton may have allowed himself to be misled by the analogy presented between the seven rays of the spectrum and the notes in an octave4 ,the mystic number1 seven1 may have clung like a fibre of the web of superstition to the cloak of the great philosopher2 but the attack made by ,goethe upon the ,newtonian philosophy betrays the melancholy fact of his being diseased with the lamentable weakness of too many exalted minds--an overweening self-esteem4 ,the polarization of light1 as it has been unfortunately called--unfortunately1 as conveying an idea of determinate and different points or poles1 which only exists in hypothetical analogy--presents to us a class of phenomena which promise to unclose the mysterious doors of the molecular constitution of bodies4 ,this remarkable condition1 as produced by the reflection of light from glass at a particular angle1 was first observed by ,malus1 in #ahjh1ii when amusing himself by looking at the beams of the setting sun1 reflected from the windows of the ,luxembourg ,palace through a double refracting prism4 ,he observed that when the prism was in one position1 the windows with their golden rays were visible2 but that turned round a quarter of a circle from that position1 the reflected rays disappeared although the windows were still seen4 ,the phenomenon of double refraction was noticed1 in the first instance1 by ,erasmus ,bartholin1 in ,iceland-spar1 a crystal the primary form of which is a rhombohedron2 who perceived that the two images produced by this body were not in the same physical conditions4#ajj ,it was also studied by ,huyghens and ,sir ,isaac ,newton1 and to our countryman we owe the singular idea that a ray of light emerging from such a crystal has sides4 ,this breaking up of the beam of light into two1--which is shown by looking through a pin-hole on a card through a crystal of ,iceland spar1 when two holes become visible1 is due to the different states of tension in which the different layers constituting the crystal exist4 ,in thus separating the ray of light into two rays1 the condition called polarisation has been produced1 and by experiment we discover that the single ray has properties different from those of the compound or ordinary ray4 ,it is somewhat difficult to explain what is meant by1 and what are the conditions of1 polarised light4 ,in the first instance let us see by what methods this peculiar state may be brought about4 ,if we reflect a ray of light from the surface of any body1 fluid or solid1 but not metallic1 at an angle between #ec and #fh it undergoes what has been called plane polarisation4 ,it may also be produced by the refraction of light from several refracting surfaces acting upon the pencil of light in succession2 as by a bundle of plates of glass4 ,each surface polarises a portion of the pencil1 and the number of plates necessary to polarise a whole beam depends upon the intensity of the beam and the angle of incidence4 ,thus1 the light of a wax candle is wholly polarised by forty-seven plates of glass at an angle of #dj #da'2 while at an angle of #gi #aa' it is polarised by eight plates4 ,again1 plane polarisation may be produced by the double refraction of crystals4 ,each of the two pencils is polarised1 like light reflected from glass at an angle of #ef #de'1 but in opposite planes4 ,non-scientific readers will still ask1--,what is this mysterious condition of light which is produced by reflection and refraction at peculiar angles to the incident ray4 ,it is one of the most difficult of problems to express in popular language4 ,the conditions are1 however1 these3-- ,an ordinary ray of light will be reflected from a reflecting surface at whatever angle that surface may be placed in relation to the incident beam4 ,a polarised ray of light is not reflected in all positions of the reflecting surface4 ,an ordinary ray of light is freely transmitted through a transparent medium1 as glass1 in whatever position it may be placed relative to the source of light4 ,a polarised ray of light is not transmitted in all the positions of the permeable medium4 ,supposing a plate of glass is presented at the angle #ef to a polarised ray1 and the plane of incidence or reflexion is at right angles to the plane of polarisation of the ray1 no light is reflected4 ,if we turn the plate of glass round through #ij1 when the plane of reflexion is parallel to that of polarisation the light is reflected4 ,if we turn the plate round another #ij1 so that the plane of reflexion and of polarisation are parallel to each other1 again no light is reflected2 and if we turn it through another #ij the reflection of the ray again takes place4 ,precisely the same result takes place when1 instead of being reflected1 the polarised ray is transmitted4 ,some substances have peculiar polarizing powers3 the tourmaline is a familiar example4 ,if a slice of tourmaline is taken1 and we look at a common pencil of light through it1 we see it in whatever position we may place the transparent medium4 ,if1 however1 we look at a pencil of polarised light1 and turn the crystal round1 it will be found that in two positions the light is stopped1 and that in two other positions it passes freely through it to the eye4 ,by way of endeavouring to conceive something of what may be the conditions which determine this very mysterious state1 let us suppose each ray of light to vibrate in two planes at right angles to each other3 one wave being vertical and the other horizontal4 ,we have many examples of this compound motion4 ,the mast of a ship1 by the force with which she is urged through the water1 describes a vertical wave1 while by the roll of the billows across which she sails1 a lateral undulation is produced at the same time4 ,we may sometimes observe the same thing when a field of corn is agitated by a shifting wind on a gusty day4 ,the hypothesis therefore is1 that every ray of ordinary light consists of two rays vibrating in different planes2 and that these rays1 separated one from the other1 have the physical conditions which we call polarized4 ,the most transparent bodies may be regarded as being made up of atoms arranged in certain planes4 ,suppose the plane of lamination of any substance to be vertical in position1 it would appear that the ray which has a vertical motion passes it freely1 whereas if we turn the body round so that the planes of lamination are at right angles to the plane of vibration of the ray1 it cannot pass4 ,that some action similar to that which it is here endeavoured to express in popular language does take place1 is proved by the correctness of the results deduced by rigid mathematical analyses founded on this hypothesis4 ,there are two other conditions of the polarization of light--called circular and elliptical polarization4 ,the first is produced by light when it is twice reflected from the second surface of bodies at their angle of maximum polarization1 and the second by reflexions from the surfaces of metals at angles varying from #gj #de' to #gh #cj'4 ,the motion of the wave in the first is supposed to be circular1 or to be that which is represented by looking along the centre of a corkscrew as it is turned round4 ,at every turn of the medium effecting circular polarization the colour of the ray of light is changed after a uniform order4 ,if turned in one direction1 they change through red1 orange1 yellow1 green1 and violet2 and if in the other direction1 the colours appear in the contrary order4 ,the variety of striking effects produced by the polarization of light2 the unexpected results which have sprung from the investigation of the laws by which it is regulated2 and the singular beauty of many of its phenomena1 have made it one of the most attractive subjects of modern science4 ,ordinary light passes through transparent bodies without producing any very striking effects in its passage2 but this extraordinary beam of light has the power of insinuating itself between the molecules of bodies1 and by illuminating them1 and giving them every variety of prismatic hue1 of enabling the eye to detect something of the structure of the mass4 ,the chromatic phenomena of polarized light are so striking1 that no description can convey an adequate idea of their character4 ,spectra more beautiful and intense than the prismatic image1--systems of rings far excelling those of thin plates1--and forms of the most symmetric order1 are constantly presenting themselves1 as the polarized ray is passed through various transparent substances2 the path of the ray indicating whether the crystal has been formed round a single nucleus or axis1 or whether it has been produced by aggregation around two axes4 ,the coloured rings1 and the dark or luminous crosses which distinguish the path of the polarized ray1 are respectively due to different states of tension amongst the particles1 although those differences are so slight1 that no other means is of sufficient delicacy to detect the variation4 ,the poetry which surrounds these1 in every way1 mysterious conditions of the solar beam1 is such1 that it is with difficulty that imagination is restrained by the stern features of truth4 ,the uses of this peculiar property in great natural phenomena are not yet made known to us2 but1 since we find on every side of us the natural conditions for thus separating the beam of light1 and effecting its polarization1 there must certainly be some most important end for which it is designed by ,him who said1 8,let there be ,light40 ,it must not be forgotten that we have at command the means of showing that the chromatic phenomena of polarized light are due to atomic arrangement4 ,by altering the molecular arrangement of transparent bodies1 either by heat or by mere mechanical pressure1 the unequal tension or strain of the particles is at once indicated by means of the polarized ray of light and its rings of colour4 ,differences in the chemical constitution of bodies1 too slight to be discovered by any other mode of analysis1 can be most readily and certainly detected by this luminous investigator of the molecular forces4#aja ,although we cannot enter into an examination of all the conditions involved in the polarization of1 and the action of matter on1 ordinary light1 it will be readily conceived1 from what has been already stated1 that some most important properties are indicated1 beyond those which science has made known4 ,almost every substance in nature1 in some definite position1 appears to have the power of producing this change upon the solar ray1 as may be satisfactorily shown by examining them with a polarizing apparatus4#ajb ,the sky at all times furnishes polarized light1 which is most intense where it is blue and unclouded1 and the point of maximum polarization is varied according to the relative position of the sun and the observer4 ,a knowledge of this fact has led to the construction of a 8,solar ,clock10#ajc with which the hour can be readily determined by examining the polarized condition of the sky4 ,it has been stated1 that chemical change on the ,daguerreotype plates and on photographic papers is more readily produced by the polarized than by the ordinary sunbeam4#ajd ,if this fact be established by future investigations1 we advance a step towards the discovery so much desiderated of the part it plays in natural operations4 ,the refined and accurate investigations of ,dr4 ,faraday stand prominently forward amid those which will redeem the present age from the charge of being superficial1 and they will1 through all time1 be referred to as illustrious examples of the influence of a love of truth for truth's sake1 in entire independence of the marketable value1 which it has been unfortunately too much the fashion to regard4 ,the searching examination made by this 8interpreter of nature0 into the phenomena of electricity in all its forms1 has led him onward to trace what connexion1 if any1 existed between this great natural agent and the luminous principle4 ,by employing that subtile analyzer1 a polarized ray1 ,dr4 ,faraday has been enabled to detect and exhibit effects of a most startling character4 ,he has proved magnetism to have the power of influencing a ray of light in its passage through transparent bodies4 ,a polarized ray is passed through a piece of glass or a crystal1 or along the length of a tube filled with some transparent fluid1 and the line of its path carefully observed2 if1 when this is done1 the solid or fluid body is brought under powerful magnetic influence1 such as we have at command by making a very energetic voltaic current circulate around a bar of soft iron1 it will be found that the polarized light is disturbed2 that1 indeed1 it does not permeate the medium along the same line4#aje ,this effect is most strikingly shown in bodies of the greatest density1 and diminished in fluids1 the particles of which are easily moveable over each other1 and has not hitherto been observed in any gaseous medium4 ,the question1 therefore1 arises1--does magnetism act directly upon the ray of light1 or only indirectly1 by producing a molecular change in the body through which the ray is passing8 ,this question1 so important in its bearings upon the connexion between the great physical powers1 will1 no doubt1 before long receive a satisfactory reply4 ,a medium is necessary to the production of the result1 and1 as the density of the medium increases1 the effect is enlarged3 it would therefore appear to be due to a disturbance by magnetic force of the particles which constitute the medium employed4 ,without any desire to generalize too hastily1 we cannot but express a feeling1--amounting to a certainty in our own mind1--that those manifestations of luminous power1 connected with the phenomena of terrestrial magnetism1 which are so evident in all the circumstances attendant upon the exhibition of ,aurora ,borealis1 and those luminous clouds which are often seen1 independent of the ,northern ,lights1 that a very intimate1 relation exists between the solar radiations and that power which so strangely gives polarity to this globe of ours4 ,in connexion with the mysterious subject of solar light1 it is important that we should occupy a brief space in these pages with the phenomena of vision1 which is so directly dependent upon luminous radiation4 ,the human eye has been rightly called the 8masterpiece of divine mechanism20 its structure is complicated1 yet all the adjustments of its parts are as simple as they are perfect4 ,the eye-ball consists of four coats4 ,the cornea is the transparent coat in front of the globe2 it is the first optical surface1 and this is attached to the sclerotic membrane1 filling up the circular aperture in the white of the eye2 the choroid coat is a very delicate membrane1 lining the sclerotic1 and covered with a perfectly black pigment on the inside2 and close to this lies the most delicately reticulated membrane1 the retina1 which is1 indeed1 an extension of the optic nerve4 ,these coats enclose three humours1--the aqueous1 the vitreous1 and the crystalline humours4 ,the eye1 in its more superficial mechanical arrangements1 presents exactly the same character as a camera obscura1 the cornea and crystalline lens receiving the images of objects refracting and inverting them2 but how infinitely more beautiful are all the arrangements of the organ of vision than the dark chamber of ,baptista ,porta6#ajf ,the humours of the eye are for the purpose of correcting the aberrations of light1 which are so evident in ordinary lenses1 and for giving to the whole an achromatic character4 ,both spherical and chromatic aberration are corrected1 the latter not entirely1 and by the agency of the cornea and the crystalline lens perfect images are depicted on the retina1 in a similar way to those very charming pictures which present themselves in the table of the camera obscura4 ,the seat of vision has been generally supposed to be the retina2 but ,mariotte has shown that the base of the optic nerve1 which is immediately connected with the retina1 is incapable of conveying an impression to the brain4 ,the choroid coat1 which lies immediately behind the retina1 is regarded by ,mariotte and ,bernoulli as the more probable seat of vision4 ,the retina1 being transparent1 offers no obstruction to the passage of the light onward to the black surface of the choroid coat1 from which the vibrations are1 in all probability1 communicated to the retina and conveyed to the brain4 ,howbeit1 upon one or the other of these delicate coats a distinct image is impressed by light1 and the communication made with the brain possibly by a vibratory action4 ,we may trace up the phenomena of vision to this point2 we may conceive undulations of light1 differing in velocity and length of wave1 occasioning corresponding tremors in the neuralgic system of the eye2 but how these vibrations are to communicate correct impressions of length1 breadth1 and thickness1 no one has yet undertaken to explain4 ,it has1 however1 been justly said by ,herschel3-- 8,it is the boast of science to have been able to trace so far the refined contrivances of this most admirable organ1 not its shame to find something still concealed from scrutiny2 for1 however anatomists may differ on points of structure1 or physiologists dispute on modes of action1 there is that in what we do understand of the formation of the eye1 so similar1 and yet so infinitely superior to a product of human ingenuity2 such thought1 such care1 such refinement1 such advantage taken of the properties of natural agents used as mere instruments for accomplishing a given end1 as force upon us a conviction of deliberate choice and premeditated design1 more strongly1 perhaps1 than any single contrivance to be found whether in art or nature1 and renders its study an object of the greatest interest40#ajg ,has the reader ever asked himself why it is1 having two eyes1 and consequently two pictures produced upon the tablets of vision1 that we see only one object8 ,according to the law of visible direction1 all the rays passing through the crystalline lenses converge to one point upon the retina1--and as the two images are coincident and nearly identical1 they can only produce the sensation of one upon the brain4 ,when we look at any round object1 as the ornamented moderator lamp before us1 first with one eye1 and then with the other1 we discover that1 with the right eye1 we see most of the right-hand side of the lamp1 and with the left eye more of the left-hand side4 ,these two images are combined1 and we see an object which we know to be round4 ,this is illustrated in a most interesting manner by the little optical instrument1 the ,stereoscope4 ,it consists either of two mirrors placed each at an angle of #de1 or of two semi-lenses turned with their curved sides towards each other4 ,to view its phenomena1 two pictures are obtained by the camera obscura on photographic paper of any object in two positions1 corresponding with the conditions of viewing it with the two eyes4 ,by the mirrors or the lenses these dissimilar pictures are combined within the eye1 and the vision of an actually solid object is produced from the pictures represented on a plane surface4 ,hence the name of the instrument2 which signifies1 ,solid ,i see4 ,analogy is often of great value in indicating the direction in which to seek for a truth2 but analogical evidence1 unless where the resemblance is very striking1 should be received with caution4 ,mankind are so ready to leap to conclusions without the labour necessary for a faithful elucidation of the truth1 that too often a few points of resemblance are seized upon1 and an inference is drawn which is calculated to mislead4 ,there is an idea that the phenomena of sound bear a relation to those of light1--that there exists a resemblance between the chromatic and the diatonic scales4 ,sound1 we know1 is conveyed by the beating of material particles--the air--upon the auditory membrane of the ear1 which have been set in motion by some distant disturbance of the medium through which it passes4 ,light has been supposed to act on the optic nerve in the same manner4 ,if we imagine colour to be the result of vibrations of different velocities and lengths1 we can understand that under some of these tremors1 first established on the nerves1 and through them conveyed to the brain1 sensations of pain or pleasure may result1 in the same way as sharp or subdued sounds are disagreeable or otherwise4 ,intensely coloured bodies do make an impression upon perfectly blind men2 and those who1 being born blind1 know no condition of light or colour1 will point out a difference between strongly illuminated red and yellow media4 ,when the eyes are closed we are sensible to luminous influence1 and even to differences of colour4 ,we must consequently infer that light produces some peculiar action upon the system of nerves in general2 this may or may not be independent of the chemical agency of the solar radiations2 but certainly the excitement is not owing to any calorific influence4 ,the system of nerves in the eye is more delicately organized1 and of course peculiarly adapted to all the necessities of vision4 ,thus far some analogy does appear to exist between light and sound2 but the phenomena of the one are so much more refined than those of the other--the impressions being all of them of a far more complicated character1 that we must not be led too far by the analogical evidence in referring light1 like sound1 to mere material motion4 ,it was a beautiful idea that real impressions of external objects are made upon the seat of vision1 and that they are viewed1 as in a picture1 by something behind the screen1--that these pictures become dormant1 but are capable of being revived by the operations of the mind in peculiar conditions2 but we can only regard it as a philosophical speculation of a poetic character1 the truth or falsehood of which we are never likely to be enabled to establish4#ajh ,that which sees will never itself be visible4 ,the secret principle of sensation1--the mystery of the life that is in us1--will never be unfolded to finite minds4 ,numerous experiments have been made from time to time on the influence of light upon animal life4 ,it has been proved that the excitement of the solar rays is too great for the healthful growth of young animals2 but1 at the same time1 it appears probable that the development of the functional organs of animals requires1 in some way1 the influence of the solar rays4 ,this might1 indeed1 have been inferred from the discovery that animal life ceases in situations from which light is absolutely excluded4 ,the instance of the ,proteus of the ,illyrian lakes may appear against this conclusion4 ,this remarkable creature is found in the deep and dark recesses of the calcareous rocks of ,adelsburg1 at ,sittich2 and it is stated1 also in ,sicily1 and in the ,mammoth caves of ,kentucky4 ,sir ,humphry ,davy describes the ,proteus anguinus as 8an animal to whom the presence of light is not essential1 and who can live indifferently in air and in water1 on the surface of the rock1 or in the depths of the mud40 ,the geological character of rocks1 however1 renders it extremely probable that these animals may have descended with the water1 percolating through fissures from very near the surface of the ground4 ,all the facts with which science has made us acquainted--and both natural and physical science has been labouring with most untiring industry in the pursuit of truth--go to prove that light is absolutely necessary to organization4 ,it is possible the influence of the solar radiations may extend beyond the powers of the human senses to detect luminous or thermic action1 and that consequently a development of animal and vegetable forms may occur where the human eye can detect no light2 and under such conditions the ,proteus may be produced in its cavernous abodes1 and also those creatures which live buried deep in mud4 ,some further consideration of the probable agency of light will occupy us1 when we come to examine the phenomena of vital forces4 ,light is essentially necessary to vegetable life2 and to it science refers the powers which the plant possesses of separating carbon from the air breathed by the leaves1 and secreting it within its tissues for the purpose of adding to its woody structure4 ,as1 however1 we have1 in the growing plant1 the action of several physical powers exerted to different ends at the same time1 the remarkable facts which connect themselves with vegetable chemistry and physiology are deferred for a separate examination4 ,the power of the solar rays to produce in bodies that peculiar gleaming light which we call phosphorescence1 and the curious conditions under which this phenomenon is sometimes apparent1 independent of the sun's direct influence1 present a very remarkable chapter in the science of luminous powers4 ,the phosphorescence of animals is amongst the most surprising of nature's phenomena1 and it is not the less so from our almost entire ignorance of the cause of it4 ,many very poetical fancies have been applied in description of these luminous creations2 and imagination has found reason why they should be gifted with these extraordinary powers4 ,the glow-worm lights her lamp to lure her lover to her bower1 and the luminous animalcules of the ocean are employed in lighting up the fathomless depths where the sun's rays cannot penetrate1 to aid its monsters in their search for prey4 8,the lamp of love--the pharos--the telegraph of the night1--which scintillates and marks1 in the silence of darkness1 the spot appointed for the lover's rendezvous10#aji is but a pretty fiction2 for the glow-worm shines in its infant state1 in that of the larva1 and when in its aurelian condition4 ,of the dark depths of the ocean it may be safely affirmed that no organized creation lives or moves in its grave-like silence to require this fairy aid4 ,fiction has frequently borrowed her creations from science4 ,in these cases science appears to have made free with the rights of fiction4 ,the glow-worms 7lampyris noctiluca71 it is well known1 have the power of emitting from their bodies a beautiful pale bluish-white light1 shining during the hours of night in the hedge-row1 like crystal spheres4 ,it appears1 from the observations of naturalists1 that these insects never exhibit their light without some motion of the body or legs2--from this it would seem that the phosphorescence was dependent upon nervous action1 regulated at pleasure by the insect2 for they certainly have the power of obscuring it entirely4 ,if the glow-worm is crushed1 and the hands or face are rubbed with it1 luminous streaks1 similar to those produced by phosphorus1 appear4 ,they shine with greatly increased brilliancy in oxygen gas and in nitrous oxide4 ,from these facts may we not infer that the process by which this luminosity is produced1 whatever it may be1 has a strong resemblance to that of respiration8 ,there are several varieties of flies1 and three species of beetles of the genus ,elater1 which have the power of emitting luminous rays4 ,the great lantern-fly of ,south ,america is one of the most brilliant1 a single insect giving sufficient light to enable a person to read4 ,in ,surinam a very numerous class of these insects are found1 which often illuminate the air in a remarkable manner4 ,in some of the bogs of ,ireland a worm exists which gives out a bright green light2 and there are many other kinds of creatures which1 under certain circumstances1 become luminous in the dark4 ,this is always dependent upon vitality2 for all these animals1 when deprived of life1 cease to shine4 ,at the same time we have many very curious instances of phosphorescence in dead animal and vegetable matter2 the lobster among the ,crustacea1 and the whiting among fishes1 are striking examples2 decayed wood also emits much light under certain conditions of the atmosphere4 ,this development of light does not appear to be at all dependent upon putrefaction2 indeed1 as this process progresses1 the luminosity diminishes4 ,we cannot but imagine that this light is owing1 in the first place1 to direct absorption by1 and fixation within1 the corpuscular structure of those bodies1 and that it is developed by the decomposition of the particles under the influence of our oxygenous atmosphere4 ,the pale light emitted by phosphorus in the dark is well known2 and this is evidently only a species of slow combustion1 a combination of the phosphorus with the oxygen of the air4 ,where there is no oxygen1 phosphorus will not shine2 its combustion in chlorine or iodine vapour is a phenomenon of a totally different character from that which we are now considering4 ,this phosphorescence of animal and vegetable matter has been regarded as something different from the slow combustion of phosphorus2 but1 upon examination1 all the chemical conditions are found to be the same1 and it is certainly due to a similar chemical change4 ,the luminous matter of the dead whiting or the mackerel may be separated by a solution of common salt or of sulphate of magnesia2 by concentrating these solutions the light disappears2 but it is again emitted when the fluid is diluted4 ,the entire subject is1 however1 involved in the mystery of ignorance1 although it is a matter quite within the scope of any industrious observer4 ,the self-emitted light of the carbuncle of the romancer is realized in these remarkable phenomena4 ,the phosphorescence of some plants and flowers is not1 perhaps1 of the same order as that which belongs to either of the conditions we have been considering4 ,it appears to be due rather to an absorption of light and its subsequent liberation4 ,if a nasturtium is plucked during sunshine1 and carried into a dark room1 the eye1 after it has reposed for a short time1 will discover the flower by a light emitted from its leaves4 ,the following remarkable example1 and an explanation of it by the poet ,goethe1 is instructive3-- 8,on the #aith of ,june1 #agii1 late in the evening1 when the twilight was deepening into a clear night1 as ,i was walking up and down the garden with a friend1 we very distinctly observed a flame-like appearance near the oriental poppy1 the flowers of which are remarkable for their powerful red colour4 ,we approached the place1 and looked attentively at the flowers1 but could perceive nothing further1 till at last1 by passing and repassing repeatedly1 while we looked side-ways on them1 we succeeded in renewing the appearance as often as we pleased4 ,it proved to be a physiological phenomenon1 and the apparent corruscation was nothing but the spectrum of the flower in the complementary blue-green colour4 ,the twilight accounts for the eye being in a perfect state of repose1 and thus very susceptible1 and the colour of the poppy is sufficiently powerful in the summer twilight of the longest days to act with full effect1 and produce a complementary image40#aaj ,the leaves of the nothera macrocarpa are said to exhibit phosphoric light when the air is highly charged with electricity4 ,the agarics of the olive-grounds of ,montpelier have been observed to be luminous at night2 but they are said to exhibit no light1 even in darkness1 during the day4 ,the subterranean passages of the coal mines near ,dresden are illuminated by the phosphorescent light of the rhizomorpha phosphoreus1 a peculiar fungus4 ,on the leaves of the ,pindoba palm1 a species of agaric grows which is exceedingly luminous at night2 and many varieties of the lichens1 creeping along the roofs of caverns1 lend to them an air of enchantment by the soft and clear light which they diffuse4 ,in a small cave near ,penryn1 a luminous moss is abundant2 and it is also found in the mines of ,hesse4 ,according to ,heinzmann1 the rhizomorpha subterranea and aidul are also phosphorescent4 ,it is but lately that a plant which abounds in the jungles in the ,madura district of the ,east ,indies was sent to this country1 which1 although dead1 was remarkably phosphorescent2 and1 when in the living state1 the light which it emitted was extraordinarily vivid1 illuminating the ground for some distance4 ,those remarkable effects may be due1 in some cases1 to the separation of phosphuretted hydrogen from decomposing matter1 and1 in others1 to some peculiar electric manifestation4 ,the phosphorescence of the sea1 or that condition called by fishermen brimy1 when the surface1 being struck by an oar1 or the paddle-wheels of a steamer1 gives out large quantities of light1 has been attributed to the presence of myriads of minute insects which have the power of emitting light when irritated4 ,the night-shining nereis 7,nereis noctiluca7 emits a light of great brilliancy1 as do several kinds of the mollusca4 ,the nereides attach themselves to the scales of fishes1 and thus frequently render them exceedingly luminous4 ,some of the crustace possess the same remarkable property2--twelve different species of cancer were taken up by the naturalists of the ,zaire in the ,gulf of ,guinea4#aaa ,the cancer fulgens1 discovered by ,sir ,joseph ,banks1 is enabled to illuminate its whole body1 and emits vivid flashes of light4 ,many of the medus also exhibit powerful phosphorescence4#aab ,these noctilucous creatures are1 many of them1 exceedingly minute1 several thousands being found in a tea-cup of sea water4 ,they float near the surface in countless myriads1 and when disturbed they give out brilliant scintillations1 often leaving a train of light behind them4#aac ,by microscopic examination no other fact has been elicited than that these minute beings contain a fluid which1 when squeezed out1 leaves a line of light upon the surface of water4 ,the appearance of these creatures is almost invariably on the eve of some change of weather1 which would lead us to suppose that their luminous phenomena must be connected with electrical excitation2 and of this1 the investigations of ,mr4 ,c4 ,peach1 of ,fowey1 communicated to the ,british ,association at ,birmingham1 furnish the most satisfactory proofs we have as yet obtained4 ,benvenuto ,cellini gave a curious account of a carbuncle which shone with great brilliancy in the dark4#aad ,the same thing has been stated of the diamond2 but it appears to be necessary to procure these emissions of light1 that the minerals should be first warmed near a fire4 ,from this it may be inferred that the luminous appearance is of a similar character to that of fluor spar1 and of numerous other earthy minerals1 which1 when exposed to heat1 phosphoresce with great brilliancy4 ,phosphorescent glow can also be excited in similar bodies by electricity1 as was first pointed out by ,father ,beccaria1 and confirmed by ,mr4 ,pearsall4#aae ,these effects1 it must be remembered1 are distinct from the electric spark manifested upon breaking white sugar in the dark1 or scratching sulphuret of zinc4 ,in the instances adduced there is not necessarily any exposure to the sunshine required4 ,it is probable that two1 if not three1 distinct phenomena are concerned in the cases above quoted1 and that all of them are distinct from animal phosphorescence1 or the luminous appearance of vegetables4 ,they1 however1 certainly prove1 either that light is capable of becoming latent1 or that it is only a condition of matter1 in which it may be made manifest by any disturbance of the molecular forces4 ,we have1 in answer to this1 very distinct evidence that some bodies do derive this property from the solar rays4 ,canton's phosphorus1 which is a sulphuret of calcium1 will1 having been exposed to the sun1 continue luminous for some time after it is carried into the dark2 as will also the ,bolognian stone1--a sulphuret of barium4 ,this result appears to be due to a particular class of the solar rays2 for it has been found1 if these sulphurets1 spread smoothly on paper1 are exposed to the influence of the solar spectrum for some little time1 and then examined in the dark1 that luminous spaces appear1 exactly corresponding with the most refrangible rays1 or those which excite chemical change2 and one very remarkable fact must not be forgotten--the dark rays of the spectrum beyond the violet produce a lively phosphorescence1 which is extinguished by the action of the rays of least refrangibility1 or the heat rays--whilst artificial heat1 such as a warm iron1 produces a very considerable elevation of the phosphorescent effect4#aaf ,it is not improbable1 that the fluorescent rays of ,mr4 ,stokes may be materially concerned in producing the phenomena of phosphorescence3 experiments are1 however1 required to prove this4 ,in these allied phenomena we have effects which are evidently dependent upon several dissimilar causes4 ,the phosphorescence of the living animal is due1 without doubt1 to nervous excitation3 that of the living vegetable to solar luminous influence2 and in the case of the mosses of caverns1 c4 to the chemical agency of the sun's rays1 which appears to be capable of conduction4 ,in the dead organic matter we have a purely chemical action developing the light1 and in the inorganic bodies we have peculiar molecular constitution1 by which an absorption of light appears to take place4 ,the subject is one of the greatest difficulty2 the torch of science is too dim to enable us to see the causes at work in producing these marvellous effects4 ,the investigation leads1 to a certain extent1 to the elucidation of many of the secrets of luminous action2 and the determination of the question1 whether light is an emanation from the sun1 or only a subtile principle diffused through all matter1 which is excited by solar influence1 is intimately connected with the inquiry4 ,it has been stated that matter is necessary to the development of light2 that no luminous effect would be produced if it were not for the presence of matter4 ,of this we not only have no proof1 but such evidence as we have is against the position4 ,there is no loss of light in the most perfect vacuum we can produce by any artificial means1 which should be the case if matter was concerned in the phenomena of light1 as a cause4 ,colour is certainly a property regulated by material bodies2 or rather1 the presence of matter is necessary to the production of colour4 ,chlorine gas is a pale yellow1 and nitrous vapour a yellowish red4 ,these and one or two other vapours1 which are near the point of condensation into fluids1 are the only coloured gaseous or vaporiform bodies4 ,the sky is blue1 because the material particles of the atmosphere reflect back the blue rays4 ,but we have more practical illustrations than this4 ,the flame of hydrogen burning with oxygen gives scarcely any light2 allow it to impinge on lime1 a portion of which is carried off by the heat of the flame1 and the most intense artificial light with which we are acquainted is produced4 ,hydrogen gas alone gives a flame in which nearly all but the blue rays are wanting3 place a brush of steel or asbestos in it1 and many of the other rays are at once produced4 ,an argand lamp1 and more particularly the lamp in which camphine--a purified turpentine1--is burnt1 gives a flame which emits most of the rays found in sunlight4 ,spirit of wine mixed with water1 warmed and ignited1 gives only yellow rays2 add nitrate of strontian and they become red2 but nitrate of barytes being mixed with the fluid1 they are changed to green and yellow2 salts of copper afford fine blue rays1 and common salt intense yellow ones4 ,many of these coloured rays and others can be produced in great power by the use of various solid bodies introduced into flame4 ,this has not been sufficiently pointed out by authors2 but it is clear from experiments that light requires the presence of matter to enable it to diffuse its coloured glories4 ,how is it that the oxygen and hydrogen flame gives so little light1 and with a solid body present1 pours forth such a flood of brilliancy8 ,the production of artificial light by electrical and chemical agencies will necessarily find some consideration under their respective heads4 ,there are numerous phenomena which connect themselves with luminous power1 or appear to do so1 which1 in the present state of our knowledge1 cannot come immediately under our attention4 ,we are compelled to reserve our limited space for those branches of science which we are enabled to connect with the great natural operations constantly going on around us4 ,many of these more abstruse results will1 however1 receive some incidental notice when we come to examine the operation of the combined physical forces on matter4 ,we see in light a principle which1 if it has not its source in the sun1 is certainly dependent upon that luminary for its manifestations and powers4 ,from that 8fountain of light0 we find this principle travelling to us at a speed which almost approaches the quickness of thought itself2 yet by the refinements of science we have been enabled to measure its velocity with the utmost accuracy4 ,the immortal poet of our own land and language1 in his creations of ,ariel1 that 8tricksy spirit10 who could creep like music upon the waters1 and of the fantastic ,puck1 who could girdle the earth in thirty minutes1 appears to have approached to the highest point to which mere imagination could carry the human mind as to the powers of things ethereal4 ,science has1 since then1 shown to man that this 8spirit1 fine spirit10 was a laggard in his tasks1 and a gross piece of matter1 when compared with the subtile essences which man1 like a nobler ,prospero1 has now subdued to do him service4 ,light is necessary to life2 the world was a dead chaos before its creation1 and mute disorder would again be the consequence of its annihilation4 ,every charm which spreads itself over this rolling globe is directly dependent upon luminous power4 ,colours1 and probably1 forms1 are the result of light2 certainly the consequence of solar radiations4 ,we know much of the mysterious influences of this great agent1 but we know nothing of the principle itself4 ,the solar beam has been tortured through prismatic glasses and natural crystals2 every chemical agent has been tried upon it1 every electrical force in the most excited state brought to bear upon its operations1 with a view to the discovery of the most refined of earthly agencies2 but it has passed through every trial without revealing its secrets1 and even the effects which it produces in its path are unexplained problems1 still to tax the intellect of man4 ,every animal and every plant alike proclaim that life and health are due to light2 and even the crystallizing forms of inorganic matter1 by bending towards it1 confess its all-prevailing sway4 ,from the sun to each planet revolving around that orb1 and to the remotest stars which gleam through the vast immensity of heaven1 we discover this power still in its brightness1 giving beauty and order to these unnumbered creations2 no less completely than to this small island of the universe which we call our ,earth4 ,through every form of matter we can mark its power1 and from all1 we can1 under certain conditions1 evoke it in lustre and activity4 ,over all and through all light spreads its ethereal force1 and manifests1 in all its operations1 powers which might well exalt the mind of ,plato to the idea of an omniscient and omnipresent ,god4 ,science1 with her ,ithuriel wand1 has1 however1 shown that light is itself the effect of a yet more exalted cause1 which we cannot reach4 ,indeed1 the attentive study of the fine abstractions of science lifts the mind from the grossness of matter1 step by step1 to the refinements of immateriality1 and there appear1 shadowed out beyond the physical forces which man can test and try1 other powers still ascending1 until they reach the ,source of every good and every perfect gift4 ,,footnotes3 #hd 8,these--oxygen1 hydrogen1 nitrogen1 and carbon--are the four bodies1 in fact1 which1 becoming animated at the fire of the sun1 the true torch of ,prometheus1 approve themselves upon the earth the eternal agents of organisation1 of sensation1 of motion and of thought40--,dumas1 ,leons de ,philosophie ,chimique1 p4 #ajj4 ,paris1 #ahcg4 #he ,it will be found in examining any of the works of the alchemists1--particularly those of ,geber1 ,de inveniendi arte ,auri et ,argenti1 and his ,de ,alchemi2 ,roger ,bacon's ,opus ,majus1 or ,alchymia ,major2 ,helvetius' ,brief of the ,golden ,calf2 or ,basil ,valentine's ,currus ,triumphalis1--that in the processes of transmutation the solar light was supposed to be marvellously effective4 ,in ,boyle's ,sceptical ,chemist the same idea will be found pervading it4 ,amid all their errors1 the alchemists were assiduous workmen1 and to them we are indebted for numerous facts4 ,of them1 and of their age1 as contrasted with our own1 ,gibbon remarks3--8,congenial to the avarice of the human heart1 it was studied in ,china1 as in ,europe1 with equal eagerness and equal success4 ,the darkness of the middle ages ensured a favourable reception to every tale of wonder2 and the revival of learning gave new vigour to hope1 and suggested more specious arts of deception4 ,philosophy1 with the aid of experience1 has at length banished the study of alchemy2 and the present age1 however desirous of riches1 is content to seek them by the humbler means of commerce and industry40--,decline and ,fall1 vol4 ii4 p4 #acg4 #hf ,on the two theories the following maybe consulted3--,young1 ,supplement to ,encyclopdia ,britannica1 article ,chromatics2 ,fresnel1 ,supplment la ,traduction ,franaise de la #e;ime dition du ,trait de ,chimie de ,thomson1 par ,riffault1 ,paris1 #ahbb2 ,herschel's ,article1 ,light1 in the ,encyclopdia ,metropolitana1 and the ,french ,translation of it by ,quetelet and ,verhulst2 ,airy's ,tract on the ,undulatory ,theory1 in his ,tracts1 #bnd edition1 ,cambridge1 #ahca2 ,powel1 ,the ,undulatory ,theory applied to ,dispersion1 c4 p4 #ahd2 ,lloyd's ,lectures1 ,dublin1 #ahcf-da2 ,cauchy1 ,sur le ,mouvement des ,corps lastiques1 ,mmoires de l',institut1 #ahbg1 vol4 ix4 p4 #aad2 ,thorie de la ,lumire1 ,ibid4 vol4 x4 p4 #bic2 ,m',cullagh1 ,on ,double ,refraction1 ,ibid41 vol4 xvi42 ,geometrical ,propositions applied to the ,wave ,theory of ,light1 ,ibid41 vol4 xvii42 ,sir ,david ,brewster's papers in the ,transactions of the ,royal ,society of ,edinburgh1 and the ,philosophical ,magazine4 #hg ,results of ,astronomical ,observations made during the years #ahcd-ch1 at the ,cape of ,good ,hope1 c4 ,by ,sir ,john ,herschel1 ,bart41 ,k4,h41 ,d4,c4,l41 ,f4,r4,s4--8,in the contemplation of the infinite1 in number and in magnitude1 the mind ever fails us4 ,we stand appalled before this mighty spectre of boundless space1 and faltering reason sinks under the load of its bursting conceptions4 ,but1 placed as we are on the great locomotive of our system1 destined surely to complete at least one round of its ethereal course1 and learning that we can make no apparent advance on our sidereal journey1 we pant with new ardour for that distant bourne which we constantly approach without the possibility of reaching it4 ,in feeling this disappointment1 and patiently bearing it1 let us endeavour to realise the great truth from which it flows4 ,it cannot occupy our mind without exalting and improving it40--,sir ,d4 ,brewster3 ,north ,british ,review4 #hh ,for examples of this1 consult ,graham's ,elements of ,chemistry2 ,brande's ,manual of ,chemistry2 or1 indeed1 any work treating of the science4 ,the formation of ink1 by mixing two colourless solutions1 one of gallic acid and another of sulphate of iron1 may be taken as a familiar instance4 #hi ,sir ,john ,herschel1 in his paper ,on the ,chemical ,action of the ,rays of the ,solar ,spectrum on ,preparations of ,silver1 remarks that1 8it may seem too hazardous to look for the cause of this very singular phenomenon in a real difference between the chemical agencies of those rays which issue from the central portion of the sun's disc1 and those which1 emanating from its borders1 have undergone the absorptive action of a much greater depth of its atmosphere2 and yet ,i confess myself somewhat at a loss what other cause to assign for it4 ,it must suffice1 however1 to have thrown out the hint2 remarking only1 that ,i have other1 and1 ,i am disposed to think1 decisive evidence 7which will find its place elsewhere7 of the existence of an absorptive solar atmosphere1 extending beyond the luminous one4 ,the breadth of the border1 ,i should observe1 is small1 not exceeding #je or #a_/g part of the sun's radius1 and this1 from the circumstances of the experiment1 must necessarily err in excess40--,philosophical ,transactions1 #ahdj4 #ij ,experiments and ,observations on some ,cases of ,lines in the ,prismatic ,spectrum1 produced by the passage of ,light through ,coloured ,vapours and ,gases1 and from certain ,coloured ,flames4 ,by ,w4 ,a4 ,miller1 ,m4,d41 ,f4,r4,s41 ,professor of ,chemistry in ,king's ,college1 ,london4--,philosophical ,magazine1 vol4 xxvii4 #ia ,report on the ,mollusca and ,radiata of the gean ,sea1 and on their distribution1 considered as bearing on ,geology4 ,by ,edward ,forbes1 ,f4,r4,s41 c4--,reports of the ,british ,association1 vol4 xii4 ,professor ,forbes remarks3--8,a comparison of the testacea1 and other animals of the lowest zones1 with those of the higher1 exhibits a very great distinction in the hues of the species1 those of the depths being1 for the most part1 white or colourless1 while those of the higher regions1 in a great number of instances1 exhibit brilliant combinations of colour4 ,the results of an enquiry into this subject are as follows3-- 8,the majority of shells of the lowest zone are white or transparent2 if tinted rose is the hue1 a very few exhibit markings of another colour4 ,in the seventh region1 white species are also very abundant1 though by no means forming a proportion so great as the eighth4 ,brownish red1 the prevalent hue of the brachiopoda1 also gives a character of colour to the fauna of this zone2 the crustacea found in it are red4 ,in the sixth zone the colours become brighter1 reds and yellows prevailing1--generally1 however1 uniformly colouring the shell4 ,in the fifth region many species are banded or clouded with various combinations of colours1 and the number of white species has greatly diminished4 ,in the fourth1 purple hues are frequent1 and contrasts of colour common4 ,in the second and third1 green and blue tints are met with1 sometimes very vivid2 but the gayest combinations of colour are seen in the littoral zone1 as well as the most brilliant whites4 8,the animals of ,testacea1 and the ,radiata of the higher zones1 are much more brilliantly coloured than those of the lower1 where they are usually white1 whatever the hue of the shell may be4 ,thus the genus ,trochus is an example of a group of forms mostly presenting the most brilliant hues both of shell and animal2 but whilst the animals of such species as inhabit the littoral zone are gaily chequered with many vivid hues1 those of the greater depth1 though their shells are almost as brightly covered as the coverings of their allies nearer the surface1 have their animals1 for the most part1 of a uniform yellow or reddish hue1 or else entirely white4 ,the chief cause of this increase of intensity of colour as we ascend is1 doubtless1 the increased amount of light above a certain depth40--p4 #agb4 #ib 4 ,on the ,epipolic ,dispersion of ,light1 being a paper entitled1 ,on a case of ,superficial ,colour presented1 by a homogeneous liquid internally colourless4 ,by ,sir ,j4 ,f4 ,w4 ,herschel1 ,bart1 ,k4,h41 ,f4,r4,s41 c4--,an epipolized beam of light 7meaning thereby a beam which has once been transmitted through a quiniferous solution1 and undergone its dispersing action7 is incapable of further undergoing epipolic dispersion4 ,in proof of this the following experiment may be adduced1-- ,a glass jar being filled with a quiniferous solution1 a piece of plate glass was immersed in it vertically1 so as to be entirely covered1 and to present one face directly to the incident light4 ,in this situation1 when viewed by an eye almost perpendicularly over it1 so as to graze either surface very obliquely1 neither the anterior nor posterior face showed the slightest trace of epipolic colour4 ,now1 the light1 at its egress from the immersed glass1 entered the liquid under precisely the same circumstances as that which1 when traversing the anterior surface of the glass jar1 underwent epipolic dispersion on first entering the liquid4 ,it had1 therefore1 lost a property which it originally possessed1 and could not1 therefore1 be considered qualitatively the same light4--,philosophical ,transactions1 vol4 cxxxvi4 #ic ,in connection with this view1 the ,newtonian theory should be consulted1 for which see--,a ,letter of ,mr4 ,isaac ,newton1 ,professor of the ,mathematicks in the ,university of ,cambridge2 containing his new ,theory about ,light and ,colors3 sent by the ,author to the ,publisher1 from ,cambridge1 ,feb4 #f1 #afga-gb1 in order to be communicated to the ,royal ,society4 #id ,in that admirable work1 ,the ,physical ,atlas of ,dr4 ,berghaus1 of which a very complete edition by ,alexander ,keith ,johnstone is published in this country1 the following order of the distribution of plants is given3-- #a4 ,the region of palms and bananas ,equatorial zone4 #b4 ,tree ferns and figs ,tropical zone4 #c4 ,myrtles and laurels ,sub-tropical zone4 #d4 ,evergreen trees ,warm temperate zone4 #e4 ,european trees ,cold temperate zone4 #f4 ,pines ,sub-arctic zone4 #g4 ,rhododendrons ,arctic zone4 #h4 ,alpine plants ,polar zone4 ,consult ,humboldt1 ,essai sur la ,gographie des ,plantes1 ,paris1 #ahjg2 ,de ,distributione ,geographic ,plantarum1 ,paris1 #ahag4 ,schouw1 ,grundzge der ,pflanzengeographie4 ,also his ,earth1 ,plants1 and ,man2 translated by ,henfrey1 in ,bohn's ,scientific ,library4 ,lamouroux1 ,gographie ,physique4 ,the ,plant1 a ,biography3 by ,schleiden2 translated by ,henfrey4 ,physical ,geography3 by ,mrs4 ,somerville4 #ie ,fraunhofer's measure of illuminating power is as follows3-- ,at the #bbnd degree of the red #jjcb #cdth degree of the red #jjid #bbnd degree of the orange #jfdj #ajth degree of the yellow #ajjj #dbnd degree of the yellow #jdhj #bnd degree of the blue #jagj #afth degree of the indigo #jjca #dcrd degree of the violet #jjjef #if ,herschel1 ,on the ,action of ,crystallized ,bodies on ,homogeneous ,light1 and on the causes of the deviation from ,newtons scale in the tints which many of them develope on exposure to a polarized ray4--,phil4 ,trans41 vol4 cx41 p4 #hh4 #ig ,on the ,nature of ,light and ,colours3 ,lecture #ci1 in ,young's ,lectures on ,natural ,philosophy1 ,kelland's ,edition1 p4 #cgc1 and the authorities there quoted4 #ih ,brewster's ,optics3 ,lardner's ,cabinet ,cyclopdia4 ,herschel1 ,on ,light3 ,encyclopdia ,metropolitana4 #ii ,malus1 ,sur une ,proprit de la ,lumire ,rflchie3 ,mmoires d',arcueil4 ,numerous memoirs by ,sir ,david ,brewster1 in the ,philosophical ,transactions4 #ajj ,bartholin1 ,on ,iceland ,crystals3 ,copenhagen1 #affi4 ,an ,accompt of sundry ,experiments made and communicated by that ,learn'd ,mathematician ,dr4 ,erasmus ,bartholin1 upon a ,chrystal like ,body sent to him out of ,island3 in connection with which ,dr4 ,matthias ,paissenius writes3--,the observations of the excellent ,bartholin upon the ,island ,chrystal are1 indeed1 considerable1 as well as painful4 ,we have here1 also1 made some tryals of it upon a piece he presented me with1 which confirm his observations4 ,mean time he found it somewhat scissile and reducible by a knife into thin laminas or plates1 which1 when single1 shew'd the object single1 but laid upon one another shew'd it double2 the two images appearing the more distant from one another1 the greater the number was of those thin plates laid on one another4 ,with submission to better judgements ,i think it to be a kind of ,selenites4 ,some of our curious men here were of opinion that the ,rhomboid figure proper to this stone was the cause of the appearances doubled thereby4 ,but having tryed whether in other transparent bodies of the like figure the like would happen1 we found no such thing in them1 which made us suspect some peculiarity in the very ,body of the stone4--,phil4 ,trans4 for #afgj1 vol4 v4 #aja ,on the ,application of the ,laws of ,circular ,polarization to the ,researches of ,chemistry3 by ,m4 ,biot4--,nouvelles ,annales du ,musum d',histoire ,naturelle1 vol4 iii41 and ,scientific ,memoirs1 vol4 i4 p4 #fjj4 ,on ,circular ,polarization3 by ,dr4 ,leeson4--,memoirs of the ,chemical ,society4 #ajb ,in ,sir ,david ,brewster's ,treatise ,on ,optics1 chap1 xviii41 ,on ,polarization1 the best arrangements for a polarizing apparatus will be found described4 #ajc ,this beautiful application was recently made by ,professor ,wheatstone1 the particulars of which will be found in his interesting communication4--,on a means of determining the apparent ,solar ,time by the diurnal changes of the ,plane of ,polarization at the ,northern ,pole of the ,sky3 ,report of the ,eighteenth ,meeting of the ,british ,association4 #ajd ,on the ,polarization of the ,chemical ,rays of ,light3 by ,john ,sutherland1 ,m4,d41 in which the author refers to the following experiment of ,m4 ,j4 ,e4 ,brard--8,i received the chemical rays directed into the plane of the meridian on an unsilvered glass1 under an incidence of #ce #fa'4 ,the rays reflected by the first glass were received upon a second1 under the same incidence4 ,i found that when this was turned towards the south1 the muriate of silver exposed to the invisible rays which it reflected was darkened in less than half an hour2 whereas1 when it was turned towards the west1 the muriate of silver exposed in the place where the rays ought to have been reflected1 was not darkened1 although it was left exposed for two hours4 ,it is consequently to be presumed that the chemical rays can undergo double refraction in traversing certain diaphanous bodies2 and lastly1 we may say that they enjoy the same physical properties as light in general40--,philosophical ,magazine1 vol4 xx4 ,dr4 ,leeson has stated that ,daguerreotype pictures can be taken more readily under the influence of polarized light1 than by ordinary radiation4 #aje ,on the ,magnetization of ,light1 and the ,illumination of ,magnetic ,lines of ,force3 by ,michael ,faraday1 ,d4,c4,l41 ,f4,r4,s4--,philosophical ,transactions1 vol4 cxxxvii4--,the following remarks are to the point of doubt referred to in the text4--8,the magnetic forces do not act on the ray of light directly and without the intervention of matter1 but through the mediation of the substance in which they and the ray have a simultaneous existence2 the substances and the forces giving to and receiving from each other the power of acting on the light4 ,this is shown by the non-action of a vacuum1 of air or gases1 and it is also further shown by the special degree in which different matters possess the property4 ,that magnetic force acts upon the ray of light always with the same character of manner1 and in the same direction1 independent of the different varieties of substance1 or their states of solid or liquid1 or their specific rotative force1 shows that the magnetic force and the light have a direct relation2 but that substances are necessary1 and that these act in different degrees1 shows that the magnetism and the light act on each other through the intervention of the matter4 ,recognising or perceiving matter only by its powers1 and knowing nothing of any imaginary nucleus abstract from the idea of these powers1 the phenomena described must strengthen my inclination to trust in the views ,i have advanced in reference to its nature40--,phil4 ,mag4 vol4 xxiv4 #ajf ,the invention of the camera obscura certainly belongs to ,giambattista ,porta1 and is described in his ,magi ,naturalis1 sive de ,miraculis ,rerum ,naturalium1 ,libri ,viginti2 ,antwerp1 #aefa4 ,an ,english translation made in #afeh exists1 but ,i have not seen it4 ,hooke1 in one of the earliest volumes of the ,philosophical ,transactions1 describes as new many of the phenomena mentioned by ,porta1 and particularly the images of the dark chamber4 #ajg ,herschel1 ,on ,light1--,encyclopdia ,metropolitana4 #ajh 8,i would here observe that a consideration of many such phenomena 7the obliteration and revival of photographic drawings7 has led me to regard it as not impossible that the retina itself may be photographically impressed by strong light1 and that some at least of the phenomena of visual spectra and secondary colours may arise from the sensorial perception of actual changes in progress in the physical state of that organ itself subsequent to the cessation of the direct stimulant40--,on the action of the ,rays of the ,solar ,spectrum on ,vegetable ,colours1 c43 by ,sir ,j4 ,f4 ,w4 ,herschel1 ,bart4 #aji ,dumeril4 #aaj ,theory of ,colours3 by ,goethe2 translated by ,eastlake4 #aaa ,see ,tuckey's ,narrative of the ,expedition of the ,zaire4 #aab ,the most complete examination of this subject will be found in two ,memoirs3-- #a4 ,experiments and observations on the light which is spontaneously emitted with some degree1 of permanency from various bodies4--,phil4 ,trans41 vol4 xc4 #b4 ,a continuation of the above1 with some experiments and observations on solar light1 when imbibed by ,canton's phosphorus3 by ,nathaniel ,hulm1 ,m4,d4--,phil4 ,trans41 vol4 xci42 and in the ,monograph of the ,british ,naked-eyed ,medus1 by ,professor ,edward ,forbes 7published for the ,ray ,society74 ,see ,wilson's note to the account of ,pennalata phosphorea in ,johnston's ,zoophytes1 #bnd edition4 #aac ,a ,general ,outline of the ,animal ,kingdom3 by ,thomas ,rymer ,jones1 ,f4,l4,s4--,acaleph1 p4 #fd4 ,lettre ,m4 ,dumas sur la ,phosphorescence des ,vers luisants3 par ,m4 ,ch4 ,matteucci4--,annales de ,chimie1 vol4 ix4 p4 #ga1 #ahdc4 #aad ,memoirs of ,benvenuto ,cellini--,bohn's ,standard ,library4 ,see also his ,treatise on his ,art as a ,sculptor and ,engraver4 ,florence1 #aefh4 #dto4 #aae ,phosphorescence of the ,diamond3 by ,m4 ,reiss 7,revue ,scientifique et ,industrielle1 vol4 xxiii4 p4 #ahe74--8,the diamond1 phosphorescent by insulation1 lost rapidly its phosphorescence when submitted to the action of the red rays of the solar spectrum4 ,on the contrary1 the blue rays are those which render the diamond the most luminous in the dark4 ,it is probable that the phosphorescence produced by heat is equally diminished by the action of the red rays of the solar spectrum40 ,giovanni ,battista ,beccaria published his experiments in #agfi4 ,see ,priestley's ,history of ,electricity2 and ,on the ,effects of ,electricity upon ,minerals which are ,phosphorescent by ,heat2 and ,further ,experiments on the communication of ,phosphorescence and ,colour to bodies of ,electricity2 by ,thomas ,j4 ,pearsall4--,journal of the ,royal ,institution of ,great ,britain1 ,oct4 #ahcj1 ,feb4 #ahca4--,these two memoirs contain the most complete set of experiments on this subject which have yet been made2 see ,placidus ,heinrich1 ,phosphorescenz der ,krper1 vol4 iv42 ,gmelin's ,handbuch der ,chemie1 part #a42--,on the ,phosphorescence of ,minerals1 ,brewster3 ,edinburgh ,philosophical ,journal1 vol4 i4 p4 #acg42--,the ,arial ,noctiluca1 or some ,new ,phenomena1 and a process of a factitious self shining substance3 ,boyle's ,works1 vol4 iv4 #aaf ,des ,effets produits sur les corps par les ,rayons ,solaires3 par ,m4 ,edmond ,becquerel4--,annales de ,chimie1 vol4 ix4 p4 #beg4 #ahdc4 ,m4 ,becquerel has applied the term phosphorognique to those rays producing phosphorescence4 ,,chapter ,,viii4 ,,actinism--,,chemical ,,radiations4 ,the ,sun-ray and its ,powers--,darkening of ,horn ,silver--,niepce's ,discovery--,prismatic ,spectrum--,refrangibility of ,light1 ,heat1 and ,actinism--,daguerre's ,discovery--,photography--,chemical ,effects produced by ,solar ,radiations--,absorption of ,actinism--,phenomena of the ,daguerreotype--,chemical ,change produced upon all ,bodies--,power of ,matter to restore its ,condition--,light protects from ,chemical ,change--,photographs taken in ,darkness--,chemical ,effects of ,light on organized ,forms--,chemical ,effects of ,solar ,heat--,influence of ,actinism on ,electricity--,radiations in ,darkness--,moser's ,discoveries1 c4 ,heat and light are derived from the sun1 and we have attempted to show1 not only that the phenomena of these two principles are different1 but that they can scarcely1 in the present condition of our knowledge1 be regarded as modified manifestations of one superior power4 ,associated with these two remarkable elements1 others may exist in the solar rays4 ,electrical phenomena are certainly developed by both heat and light1 and peculiar electric changes are produced by exposure to sunshine4 ,electricity may be merely excited by the solar rays1 or it may flow like light from the sun4 ,chemical action may be only due to the disturbance of some diffused principle2 or it may be directly owing to some agency which is radiated at once from the sun4 ,a sun ray is a magical thing3 we connect it in our fancy with the most ethereal of possible creations4 ,yet in its action on matter it produces colour2 it separates the particles of solid masses farther from each other1 and it breaks up some of the strongest forces of chemical affinity4 ,to modern science is entirely due the knowledge we have gained of the marvellous powers of the sunbeam2 and it has rendered us familiar with phenomena1 to which the incantation scenes of the ,cornelius ,agrippas of the dark ages were but ill-contrived delusions1 and their magic mirrors poor instruments4 ,the silver tablets of the photographic artist receiving fixed impressions of the objects represented in the dark chamber by a lens1 are far superior as examples of natural magic4 ,in the dark ages1 or rather as the earliest gleams of the bright morning of inductive research were dispelling the mists of that phantom-peopled period1 it was observed1 for the first time1 that the sun's rays turned a white compound black4 ,man must have witnessed1 long before1 that change which is constantly taking place in all vegetable colours3 some darkening by exposure to sunlight1 while others were bleached by its influence4 ,yet those phenomena excited no attention1 and the world knew nothing of the mighty changes which were constantly taking place around them4 ,the alchemists--sublime pictures of credulous humanity--toiling in the smoke of their secret laboratories1 waiting and watching for every change which could be produced by fire1 or by their 8royal waters10 caught the first faint ray of an opening truth2 and their wild fancy1 that light could change silver into gold1 if they but succeeded in getting its subtile beams to interpenetrate the metal1 was the clue afforded to the empirical philosopher to guide him through a more than ,cretan labyrinth4#aag ,the first fact recorded upon this1 point was1 that horn silver blackened when exposed to the light4 ,without doubt many anxious thoughts were given by these alchemists to that fact4 ,here was1 as it appeared1 a mixing up of light and matter1 and behold the striking change6 ,it was a step towards the realization of their dreams4 ,alas6 poor visionaries6 in pursuing an ideality they lost the reality which was within their grasp4 ,truths come slowly upon man1 and long it is before these angel visits are acknowledged by humanity4 ,the world clings to its errors1 and avoids the truth1 lest its light should betray their miserable follies4 ,at length a man of genius announced that 8,no substance can be exposed to the sun's rays without undergoing a chemical change20 but his words fell idly upon the ear4 ,his friends looked upon his light-produced pictures as singular2 they preserved them in their cabinets of curiosities2 but the truths which he enunciated were soon forgotten4 ,howbeit his words were recorded1 and it is due to the solitary experimentalist of ,chlons on the ,sane1 to couple the name of ,niepce with the discovery of a fact which is scarcely second to the development of the great law of universal gravitation4#aah ,but an examination awaits us1 which1 for its novelty1 has more charms than most branches of science1 and which1 for the extensive views it opens to the inquirer1 has an interest in nowise inferior to any other physical investigation4 ,the prismatic spectrum affords us the means of examining the conditions of the solar rays with great facility4 ,in bending the ray of white light out of its path1 by means of a triangular piece of glass1 we divide it in a remarkable manner4 ,we learn that heat is less refracted by the glass than the other powers2 we find the maximum point of the calorific rays but slightly thrown out of the right line1 which the solar pencil would have taken1 had it not been interrupted by the prism2 and the thermic action is found to diminish with much regularity on either side of this line4 ,we discover that the luminous power is subject to greater refraction1 and that its maximum lies considerably above that of heat2 and that1 in like manner1 on each side the light diminishes1 producing orange1 red1 and crimson colours below the maximum point1 and green1 blue1 and violet above it4 ,again1 we find that the radiations which produce chemical change are more refrangible than either of the others1 and the maximum of this power is found at the point where light rapidly diminishes1 and where scarcely any heat can be detected3 it extends in full activity1 above its maximum1 to a considerable distance1 where no trace of light under ordinary conditions exists1 and below that point1 until light1 appearing to act as an interfering agent1 quenches its peculiar properties4 ,these are strong evidences that light and actinism--as this principle has been named--are not identical3 and we may separate them most easily and effectually from each other4 ,certain glasses1 stained dark blue1 with oxide of cobalt1 admit scarcely any light2 but they offer no interruption to the passage of actinism or the chemical rays2 on the contrary1 a pure yellow glass1 or a yellow fluid1 which does not sensibly reduce the intensity of any one colour of the chromatic band of luminous rays1 completely cuts off this chemical principle1 whatever it may be4 ,in addition to these1 there are other results which we shall have to describe1 which prove that1 although associated in the solar beam1 light and actinism are in constant antagonism4 ,when ,daguerre first published his great discovery1 the ,european public regarded his metal tablets with feelings of wonder3 we have grown accustomed to the beautiful phenomena of this art1 and we have become acquainted with a number of no less beautiful processes on paper1 all of which1 if studied aright1 must convince the most superficial thinker1 that a world of wonder lies a little beyond our knowledge1 but within the reach of industrious and patient research4 ,photography is the name by which the art of sun-painting will be for ever known4 ,we regard this as unfortunate1 conveying as it does a false idea1--the pictures not being light-drawn4 ,could we adopt the name given by ,niepce to the process1 the difficulty would be avoided1 since ,heliography involves no hypothesis1 and strictly tells the undeniable truth1 that our pictures are sun-drawn4 ,that pictures can be produced by the rays from artificial sources1 presents no objection to this2 these rays were still originally derived from the sun4 ,by whatever name we determine to convey our ideas of these phenomena1 it is certain that they involve a series of effects which are of the highest interest to every lover of nature1 and of the utmost importance to the artist and the amateur4 ,by easy manipulation we are now enabled to give permanence to the charming pictures which are produced by means of that pleasing invention of ,baptista ,porta1 the ,camera ,obscura4 ,any image1 which being refracted by the lens of this instrument falls upon the table in its dark chamber1 may be secured with its most delicate gradations of shadows1 upon either a metallic or a paper tablet4 ,but let us proceed to the examination of a few of the more striking phenomena of these chemical changes4 ,to commence with some of the more simple but no less important results4 ,chlorine and hydrogen will not unite in darkness1 nor will chlorine and carbonic oxide2 but1 if either of those gaseous mixtures is exposed to sunshine1 they combine rapidly1 and often with explosion4 ,a solution of the sulphate of iron in ordinary water may be preserved for a long time in the dark without undergoing any change2 expose it to the sunshine1 and a precipitation of oxide of iron is very rapidly produced4 ,the mineral chameleon1 the manganesiate of potash in solution1 is almost instantly decomposed in daylight2 but it is a long time before it undergoes any change in darkness4 ,the same thing occurs with a combination of platinum and lime3 indeed1 it appears that precipitation is at all times1 and under all circumstances1 accelerated by the solar rays4 ,as these precipitations are in exact agreement with the quantity of actinic radiation to which the solutions have been exposed1 we may actually weigh off the relative quantities1 representing in grains the equivalent numbers to the amount of actinism which has influenced the chemical compound4#aai ,we have evidence which appears to prove that this chemical agent may be absorbed by simple bodies1 and that by this absorption an actual change of condition1 is produced1 in many respects analogous to those allotropic changes which we have previously considered4 ,chlorine1 in its ordinary state1 does not combine with hydrogen in the dark4 ,if we employ the yellow medium of chlorine gas1 for the purpose of analyzing the sun's rays previously to their falling upon some chemical compound which is sensitive to actinic power1 we shall find that the chlorine obstructs all this actinism1 and1 however unstable the compound1 it remains unchanged4 ,but the chlorine gas which has interrupted this wonderful agent1 appears to have absorbed it1 and it is so far altered in its constitution that it will unite with hydrogen in the dark4#abj ,in like manner1 if1 of two portions of the same solution of sulphate of iron1 one is kept in the dark and the other exposed to the sunshine1 it will be found that the solution which has been exposed will precipitate gold and silver from their combinations much more speedily than that which has been preserved in darkness--the temperature and every other condition being the same4 ,the phenomena of the ,daguerreotype involve many strange conditions4 ,a plate of silver1 on which a slight chemical action has been established by the use of iodine1 is exposed to the lenticular image in the camera obscura4 ,if allowed to remain under the influence of these radiations for a sufficient length of time1 a faithful picture of the illuminated objects is delineated on the plate1 as shown by the visible decomposition and darkening of the iodized surface4 ,the plate is not1 however1 in practice allowed to assume this condition2 after an exposure of a few seconds the radiant influence is cut off1 and the eye cannot detect any evidence of change upon the yellow plate4 ,it is now exposed to the vapour of mercury1 and that metal in a state of exceedingly fine division is condensed upon the plate2 but the condensation is not uniformly spread upon its face4 ,the deposit of mercurial vapour is in exact proportion to the amount of chemical action produced4 ,is the change1 by which this peculiar power of condensation is effected1 a chemical1 calorific1 electrical1 or merely a molecular one8 ,the evidences1 at present1 are not sufficient to determine the question4 ,it has lately been suggested1 that the mercury acts chemically only1 and effects the full decomposition of the iodide of silver2 and that the picture is due to this1 and not to the deposition actually of the mercury vapour4 ,in all probability we have the involved action of several forces4 ,we have some experiments which show1 clearly enough1 that mercury is deposited in proportions which correspond with the intensity of solar action4 ,a chemically prepared surface is not necessary to exhibit this result4 ,a polished plate of metal1 of glass1 of marble1 or a piece of painted wood1 being partially exposed1 will1 when breathed upon1 or presented to the action of mercurial vapour1 show that a disturbance has been produced upon the portions which were illuminated1 whereas no change can be detected upon the parts which were kept in the dark4 ,it was thought1 until lately1 that a few chemical compounds1 such as the iodide of silver1 the material employed in the ,daguerreotype and ,calotype1--chloride of silver1 the ordinary photographic agent1--a few salts of gold1 and one or two of lead and iron1 were the only materials upon which these very remarkable changes were produced4 ,we now know that it is impossible to expose any body1 simple or compound1 to the sun's rays1 without its being influenced by this chemical and molecular disturbing power4 ,to take our examples from inorganic nature1 the granite rock which presents its uplifted head in firmness to the driving storm1 the stones which genius has framed into forms of architectural beauty1 or the metal which is intended to commemorate the great acts of man1 and which in the human form proclaims the hero's deeds and the artist's talent1 are all alike destructively acted upon during the hours of sunshine1 and1 but for provisions of nature no less wonderful1 would soon perish under the delicate touch of the most subtile of the agencies of the universe4 ,niepce was the first to show that all bodies which underwent this change during daylight possessed the power of restoring themselves to their original conditions during the hours of night1 when this excitement was no longer influencing them4 ,resins1 the ,daguerreotype plate1 the unprepared metal tablet1 and numerous photographic preparations1 prove this in a remarkable manner4#aba ,the picture which we receive to-day1 unless we adopt some method of securing its permanency1 fades away before the morrow1 and we try to restore it in vain4 ,with some of our chemical preparations this is very remarkably shown1 but by none in so striking a manner as by paper prepared with the iodide of platinum1 which1 being impressed with an image by heliographic power1 which is represented by dark brown tints1 restores itself in the dark1 in a few minutes1 to its former state of a yellow colour1 and recovers its sensibility to sunshine4#abb ,the inference we alone can draw from all the evidences which the study of actino-chemistry affords1 is1 that the hours of darkness are as necessary to the inorganic creation as we know night and sleep to be to the organic kingdom4 ,but we must not forget that there does exist in the solar rays a balance of forces which materially modifies the amount of disturbing influence exerted by them on matter4 ,not only do we find that the chemical action is not extended over the whole length of the prismatic spectrum1 but we discover that over spaces1 which correspond with the maximum points of light and heat1 a protective action is exerted4 ,that is1 that highly sensitive photographic agents1 which blacken rapidly under exposure to diffused daylight1 are entirely protected from change in full sunshine1 if at the same time as a strong light is thrown upon them by reflection1 the yellow and extra red rays are brought to bear upon their surface4 ,not only so1 but by employing media which will cut off all the chemical rays of the spectrum1 admitting freely at the same time the luminous and calorific rays1 we find that a protected band1 the length of the spectrum1 remains white1 whilst every other portion has blackened4#abc ,among the many curious instances of natural magic1 none are more remarkable than an experiment not long since proposed1 by which ,daguerreotype pictures may be taken in absolute darkness to the human eye4 ,this is effected in the following manner3--,a large prismatic spectrum is thrown upon a lens fitted into one side of a dark chamber2 and as we know that the actinic power resides in great activity beyond the violet ray1 where there is no light1 the only rays which we allow to pass the lens into the chamber are those which are extra-spectral and non-luminous4 ,these are directed upon1 any white object1 and from that object radiated upon a highly sensitive plate in a camera obscura4 ,thus a copy of the subject will be obtained by the agency of radiations which produce no sensible effect upon the optic nerve4 ,this experiment is the converse of those which show us that we may illuminate any object with the strongest sunlight which has passed through yellow glass1 the yellow solution of sulphuret of calcium1 or of the bichromate of potash--these being non-transparent to the chemical rays--and yet fail to secure any ,daguerreotype copy of it1 even upon the most exquisitely sensitive plate4 ,indeed1 the image of the sun itself1 when setting through an atmosphere which reduces its light to a red or rich yellow colour1 not only produces no chemical change1 but protects an iodized plate from it2 and whilst every other part of the tablet gives a picture of surrounding objects in the ordinary character1 the bright sun itself is represented by a spot upon which no change has taken place4#abd ,in tropical climes1 where a brilliant sun is giving the utmost degree of illumination to all surrounding objects1 all photographic preparations are acted upon relatively more slowly than in the climate of ,england1 where the light is less intense4 ,as a remarkable instance of this fact1 a circumstance may be mentioned1 which is curiously illustrative of the power of light to interfere with actinism3-- ,a gentleman1 well acquainted with the ,daguerreotype process1 obtained in the city of ,mexico all the necessary apparatus and chemicals1 expecting1 under the bright light and cloudless skies of that climate1 to produce pictures of superior excellence4 ,failure upon failure was the result2 and although every care was used1 and every precaution adopted1 it was not until the rainy season set in that he could secure a good ,daguerreotype of any of the buildings of that southern city4 ,the first attempts1 which were made at the instigation of ,m4 ,arago1 by order of the ,french ,government1 to copy the ,egyptian tombs and temples1 and the remains of the ,aztecs in ,central ,america1 were failures4 ,although the photographers employed succeeded to admiration in ,paris1 in producing pictures in a few minutes1 they found often that an exposure of an hour was insufficient under the bright and glowing illumination of a southern sky4 ,experiments with the spectrum have been made in different latitudes1 and it is found1 that1 as we proceed towards the equator1 a band which is always left unchanged1 corresponding exactly with the rays of greatest illuminating power1 regularly enlarges in size1 thus proving the increase of light over actinism--and the interfering power of the former4 ,by increasing the sensibility of the photographic preparation1 this difficulty is overcome1 and particularly when any organic compound enters into the preparation4 ,so that we are now enabled to copy nature in all her varying moods1 whether we employ our photographic tablets in temperate ,europe1 or in tropical ,africa4 ,the degree of sensibility which has been attained is remarkable4 ,mr4 ,fox ,talbot1 by uniting a process devised by ,dr4 ,woods1 of ,parsonstown1 and another which was first introduced by the author of this volume1 and combining them with an ether1 obtains a most unstable compound1 which he thus employs4 ,a glass plate is covered with albumen united with the above solution1 and then with nitrate of silver3 this forms the sensitive surface4 ,the plate being placed in the dark1 in a camera1 it is so adjusted that the image of a printed bill fixed upon a wheel may fall upon it when uncovered1 and the wheel illuminated4 ,the wheel is made to revolve with the utmost rapidity1 in a perfectly dark room1 and the sensitive plate uncovered4 ,then the whirling bill is illuminated for an inappreciably short space of time by the discharge of a ,leyden jar4 ,notwithstanding the rapid rate at which the pointed paper is moving1 and the instantaneous nature of the illumination--a miniature flash of lightning--the bill is found to be copied with unfailing fidelity upon the photographic plate4 ,it unfortunately happens1 that the preparation by which this extraordinary degree of sensibility is obtained1 is very uncertain in its action--and hence it is not generally useful2 but here we have the evidence to show that at a speed as rapid as that of a rifle-ball an impression may be made upon a photographic plate4 ,there are1 however1 some new processes which promise eventually to rival the above for sensibility1 and to be by no means of difficult manipulation4 ,of this character is the collodion process4 ,the gun cotton dissolved in ether possesses some very great accelerating properties1 and in combination with the silver salts1 and one of the vegetable acids1 it forms a sensitive surface upon which pictures may be obtained in less than a second of time4 ,colour1 natural colour too1 has been very decidedly secured4 ,the sun has been solicited to display his palette1 and the answer has been a picture in which colour for colour in all their fidelity have been impressed4 ,the plate upon which this result has been obtained is of a dark brown colour1 and the chromatic variety is1 as it were1 eaten out by the solar rays4 ,these colours have not yet been permanently fixed upon the plate employed1 but from the temporary degree of fixedness which has been obtained1 we may fairly hope that in a short time colour may be rendered as permanent on the productions of the photographer as on those of the painter4 ,it is a curious and striking fact1 that in the preparation of these plates1 salts are used which give colours to flame2 and according to the colour which is produced by them when burning1 so1 on the photographic plate1 is that colour impressed with greater intensity than the others4 ,to what is this leading us8 ,mysteries surround our advances on the domain of truth4 ,we dare not speculate upon them3 the time of their full development will arrive4 ,by the aid of this beautiful art1 we are enabled to preserve the lineaments of those who have benefited their race by their intellect1 or their heroism4 ,we can hand down to future ages portraits of our own ,wellington1 and the illustrious ,arago1 unerring in their truthfulness4 ,how great would be the joy of all1 could we now obtain a daguerreotype portrait of a ,greek poet1 or of a ,roman philosopher1 of a ,sophocles1 or of a ,seneca6 ,how much discussion would be prevented did we possess a calotype portrait of the ,bard of ,avon1 or of the ,philosopher of ,grantham6 ,by the agency of those very rays which give life and brilliancy to the laughing eye and the roseate cheek1 we can at once correctly trace the outline of the features we admire1 with all those shadowy details which give a reality to the 8presentment40 ,the objects of our love may be for ever present with us in these self-painted pictures4 ,the vicious1 whom we would avoid1 may be made known to us by this unerring painter4 ,the process which nature employs is perfect2 the imperfections are those of man1 and these being few1 he may soon learn to remedy4 ,to the traveller1 how valuable are the processes of photography6 ,he secures representations of those remains of temples which were in their glory when ,moses wrote4 ,he copies by one operation a tomb at ,karnac1 covered with myriads of hieroglyphics1 or an inscribed stone in ,arabia1 which it would occupy him days to trace4 ,these he can carry to his home and read at his leisure4 ,the relics of hoar antiquity speaking to the present of the past1 and recording the histories of races which have fleeted away like shadows1 are thus preserved to tell their wondrous tales4 ,the admirer of nature may copy her arrangements with the utmost fidelity4 ,every modulation of the landscape1 each projecting rock or beetling tor--the sinuous river in its rapid flow--the meandering stream1 8gliding like happiness away20 and the spreading plains over which are scattered the homes of honest industry and domestic peace1 intermingled with the towers of those humble temples in which simple-hearted piety delights to 8bow the head and bend their knee20 these1 all of these1 may1 by the sunbeam which illuminates the whole1 be faithfully pencilled upon our chemical preparations4 ,our art enables us to do more even than this2 we have but to present our sensitive tablet to the moon1 and she1 by her own light1 prints her mountains and her valleys1 and indicates with all truth the physical conditions of her surface4 ,any reference to the chemical agency of ,,light--the luminous rays as distinguished from the chemical and calorific rays--has been avoided until we came to the consideration of this particular question of chemical change4 ,upon organic compounds1 as1 for instance1 upon the colouring matter of leaves and flowers1 light does exert a chemical power3 and it is found that vegetable colours are bleached1 not by rays of their own colour1 but by those which are complementary to them4 ,a red dye fades under the influence of a green ray1 and a yellow under that of a violet one1 much more speedily than when exposed to rays of any other colour2 and this1 it must be remembered1 is due to the coloured ray itself1 and not to any actinic power masked1 as it were1 behind the colour1 as is generally believed4#abe ,it was long a question whether the decomposition of carbonic acid by plants was due to the luminous or the chemical rays4 ,it is now clearly established that the luminous rays are the most active in producing this effect2 which they do indirectly1 by exciting the vital powers of the organized structures4 ,therefore we would refer this phenomenon of gaseous decomposition to a vital power quickened by luminous excitement4#abf ,we have already noticed some chemical phenomena due to heat1 particularly those experiments of ,count ,rumford's1 which appeared to him to prove that the chemical agency of the sun's rays was due to its calorific power4 ,certain chemical phenomena1 we know1 may be produced by thermic action2 but the only variety of thermo-chemical action which connects itself immediately with the solar radiations1 belongs to a class of rays to which the name of ,parathermic has been given1 and to which the scorching1 as it is called1 of plants1 the browning of the autumnal leaves1 and the ripening of fruits1 appear to be due4#abg ,when we come to the consideration of those physical phenomena which belong to the growth of plants1 all these peculiarities of solar action must be attended to in detail4 ,the manner in which we find the actinic power influencing electrical action1 also shows us that the equilibrium of forces is continued through all the great principles of nature4 ,if a galvanic arrangement is made1 by which small quantities of metals may be slowly precipitated at one of the poles in the dark1 and a similar arrangement be exposed to sunshine1 it will be found that no metal is deposited3 the sun's rays have interfered with the decomposing power of the electrical current4 ,at the same time we learn1 that by throwing a beam of light upon a plate of copper which forms one of a galvanic pair1 whilst it is under the influence of an acidulated solution1 an additional excitation takes place1 and the galvanometer will indicate the passage of an increased current of electricity4 ,these two dissimilar actions appear enigmatical2 but they may1 there is no doubt1 receive some solution from the influence of different rays on the contrary poles of the battery4 ,one thing is quite evident1--electricity suffers a disturbance of one order1 by light2 and an excitement of another by its associated principles in the sunbeam4 ,if a yellow glass is interposed between the galvanic arrangement and the sun1 the electro-chemical precipitation goes on in the same manner as it would in perfect darkness1 and no extra excitement is produced upon the plates of the battery4 ,from this it would appear that actinism and not light is to be regarded as the disturbing power4#abh ,it has already been shown that yellow media possess the power of stopping back the chemical agent4 ,we have already1 detailed many of the peculiarities of the different varieties of ,phosphori1 which would seem to be the result of light4 ,phosphorescence is probably excited by those rays which produce no direct effect upon the eye4 ,if we spread sulphuret of calcium upon paper1 and expose it to the action of the solar spectrum1 it is found to glow 7in the dark7 only over those spaces occupied by the violet rays and the ordinarily dark rays beyond them2 proving that the excitation necessary to the development of the phenomena of phosphorescence is due to a class of rays distinct from the true light-giving principle1 and more nearly allied to that principle or power which sets up chemical decomposition4 ,whether the fluorescent rays1 before mentioned1 which are found so abundantly over the space which produces the greatest phosphorescent effect1 are active in producing the phenomena1 is as yet an unsolved problem4 ,vision and colour1 calorific action1 chemical change1 molecular disturbance1 electrical phenomena1 and phosphorescent excitation1 all1 each one with a strange duality1 are connected with the sunbeam4 ,we find1 when we receive solar spectra upon iodized plates1 or on several kinds of photographic paper1 that a line1 over which no action takes place1 is preserved at the top and bottom of the impressed image1 and in many cases along the sides also4 ,the only way in which this can be accounted for1 as the spectrum represents the sun in a distorted form1 is by supposing that rays come from the edges of the sun of a different character from those which proceed from the centre of that orb4#abi ,light from the centre of the solar disc is under different conditions from that which comes from the edge of the sun3 this is due to the varying angle1 which is presented to us by a circular body3 calorific action seems to be more strongly manifested when the envelope of light1 extending like an atmosphere to the sun1 is thrown into great agitation1 and waves1 and great hollows--solar spots--are produced4 ,there is some indication of the existence of a third condition on the sun's surface1 to which probably belongs the mighty chemical power which we call actinism4 ,electricity may be1 as some have speculated1 the exciting agent2 a constant and violent ,aurora ,borealis may exist on the sun1 and under the excitation of this force the others named may be quickened into full activity4 ,that actinism is one of the great powers of creation we have abundant proof4 ,nearly all the phenomena of chemical change which have been referred to light1 are now proved to be dependent upon actinic power2 and beyond the influence which has been ascertained to be exerted by it upon all inorganic bodies1 we shall have occasion to show still further the dependence of the vegetable and animal worlds upon its agency4 ,the influence of the solar beams on vegetation is proved by common experience2 the closer examination of its action on vegetable life is reserved for the chapter devoted to its phenomena4 ,of its influence on animals nothing is very correctly known2 but some early experiments prove that they1 like other organised bodies1 are subject to all the radiant forces1 as indeed1 independent of experiment1 every observation must teach4 ,certain it is1 that organisation can take place only where the sun's rays can penetrate3 where there is unchanging darkness1 there we find all the silence of death4 ,prometheus stole fire from heaven1 and gave the sacred gift to man1 as the most useful to him of all things in his necessities3 by the aid of it he could temper the severities of climate1 render his food more digestible and agreeable1 and illuminate the hours of darkness4 ,so says the beautiful fiction of the ,grecian mind1--which appears as the poetic dream or prophetic glance of a gifted race1 who felt the mysterious truth they were yet unable to describe4 ,pheaton and ,apollo are only other foreshadowings of the creative energies which dwell in the glorious centre of our universe4 ,the poetry of the ,hellenic people ascended above the littlenesses of merely human action1 and sought to interpret the great truths of creation4 ,reflective1 they could not but see that some mysterious powers were at work around them2 imaginative1 they gave to fine idealisations the government of those inexplicable phenomena4 ,modern science has shown what vastly important offices the solar rays execute1 and that the principles discovered in a sunbeam are indeed the exciters of organic life1 and the disposers of inorganic form4 ,it must not be forgotten that we have already alluded to a speculation which supposes this actinic influence to be diffused through all nature1 to be indeed the element to which chemical force in all its forms is to be referred1 and that it is merely excited by the solar rays4 ,this hypothesis receives some support from the very peculiar manner in which chemical action once set up is carried on1 independent of all extraneous excitement1 after the first disturbance has been produced4 ,if any of the salts of gold are exposed in connection with organic matter1 as on paper1 to sunshine for a moment1 an action is begun1 which goes on unceasingly in the dark1 until the gold is reduced to its most simple state4#acj ,the same thing occurs with chromate of silver1 some of the salts of mercury1 argentine preparations combined with protosulphate of iron or gallic acid1 and some other chemical combinations4 ,these progressive influences point to some law not yet discovered1 which seems to link this radiant actinism with the chemical agent existing in all matter4 ,this problem also connects itself with another class of facts which1 although due1 in all probability1 to a great extent1 to calorific radiations1 and hence known under the general term of ,thermography1 appear to involve both chemical and electrical excitation4 ,from the investigations of ,moser and of others1 we learn the very extraordinary fact1 that even inanimate masses act and react upon each other by the influence of some dark radiations1 and seem to exchange some of the peculiarities which they possess4 ,this appears generally in the curious experiments which have been referred to1 as confined merely to form or structure4 ,thus an engraved plate will give to a polished surface of metal or glass placed near it1 after a very little time1 a neat distinct image of itself2 that is1 produce such a structural disturbance as will occasion the plate to receive vapour differently over those spaces opposite to the parts in cameo or in intaglio1 from what it does over the opposite4 ,if a piece of wood is used instead of a metal1 there will1 by similar treatment1 be produced a true picture of the wood1 even to the representation of its fibres4#aca ,it is also probable that chemical decomposition is produced by the mere juxtaposition of different bodies4 ,iodide of gold or silver1 perfectly pure1 has been placed upon a plate of glass1 and a plate of copper covered with mercury suspended over it3 a gradual decomposition of those salts is said to have been observed1 iodide of mercury to be formed1 and the gold or silver salts reduced to a finely divided metallic state4#acb ,a body whose powers of radiating heat are low1 being brought near another whose radiating powers are more extensive1 will1 in the course of a short time1 undergo such an amount of molecular disturbance as will effect a complete change in the arrangement of its surface1 and an impression of the body having the highest radiating powers will be made upon the other4 ,this impression is dormant1 but may be developed under the influence of vapour1 or of oxidation4#acc ,a body1 such as charcoal1 of low conducting power1 being placed near another1 such as copper1 which is a good conductor1 will1 in a very short time1 produce1 in like manner1 an impression of itself upon the metal plate4 ,thus any two bodies1 whose conducting or radiating powers are dissimilar1 being brought near each other1 will occasion a molecular disturbance1 or impress the one with the image of the other4 ,however small the difference may be1 an effect is perceived1 and that of the most extraordinary kind1 giving rise to the production of actual images upon each surface exposed4 ,it is thus that a print on paper may be copied on metal1 by merely suspending it near a well-polished plate of silver or copper for a few days4 ,the white and black lines radiate very differently2 consequently an effect is produced on the bright metal in the parts corresponding to the black lines1 dissimilar to that which takes place opposite to the white portions of the paper2 and1 on the application of vapour1 a true image of the one is found impressed upon the other4#acd ,bodies which are in different electrical states act upon each other in an analogous manner4 ,thus arsenic1 which is highly electro-negative1 will1 when placed near a piece of electro-positive copper1 readily impart to its surface an impression of itself1 and so in like manner will other bodies if in unlike conditions4 ,every substance physically different 7it signifies not whether as it regards colour1 chemical composition1 mechanical structure1 calorific condition1 or electrical state17 has a power of radiation by which a sensible change can be produced in a body differently constituted4 ,fable has told us that the magicians of the ,east possessed mirrors in which they could at will produce images of the absent4 ,science now shows us that representations quite sufficient to deceive the credulous can be produced on the surface of polished metals without difficulty4 ,a highly polished plate of steel may be impressed with images of any kind1 which would remain invisible1 the polished surface not being in the least degree affected1 as it regards its reflecting powers2 but by breathing over it1 the dormant images would develope themselves1 and fade away again as the condensed moisture evaporated from the surface4#ace ,these1 which are but a few selected from a series of results of an equally striking character1 serve to convince us that nature is unceasingly at work1 that every atom is possessed of properties by which it influences every other atom in the universe1 and that a most important class of natural phenomena appear to connect themselves directly with the radiant forces4 ,the alchemists observed that a change took place in chloride of silver exposed to sunshine4 ,wedgwood first took advantage of that discovery to copy pictures4 ,niepce pursued a physical investigation of the curious change1 and found that all bodies were influenced by this principle radiated from the sun4 ,daguerre produced effects from the solar pencil which no artist could approach to2 and ,talbot and others extended the application4 ,herschel took up the inquiry2 and he1 with his usual power of inductive search and of philosophical deduction1 presented the world with a class of discoveries which showed how vast a field of investigation was opening for the younger races of mankind1--a field in which a true spirit may reap the highest reward in the discovery of new facts1 and to which we must look for a further development of those great powers with which we have already some slight acquaintance1 and for the discovery of higher influences which are not yet dreamed of in our philosophy4 ,if music1 with its mysteries of sound1 ,gives to the human heart a heavenward feeling2 ,the beauty and the grandeur which are found ,spread like a vesture this fair earth around1 ,creation's wond'rous harmonies revealing1 ,and to the soul in truth's strong tongue appealing1 ,with all the magic of those secret powers1 ,which1 mingling with the lovely band of light1 ,the sun in constant undulation showers ,to mould the crystals1 and to shape the flowers1 ,or give to matter the immortal might ,of an embracing soul--should1 from this sod1 ,exalt our aspirations all to ,god4 ,,footnotes3 #aag ,see ,researches on ,light1 by the ,author4--,reference to any of the works of the alchemists will prove the prevalence of the idea expressed in the text4 ,we find that gold was considered to be always under the influence of light and solar heat4--8,it is said of gold that it waxeth cold towards daylight1 insomuch that they who wear rings of it may perceive when the day is ready to dawn40--,speculum ,mundi1 or a ,glass representing the face of the ,world4 ,cambridge1 #afdc4 #aah ,daguerre's ,report to the ,academy of ,sciences3 ,la ,daguerrotype ,historique1 et description des procds du ,daguerrotype et du ,diorama 7,paris1 #ahci72 particularly the description of ,heliography1 by ,m4 ,niepce4 ,see also the letters by ,niepce1 published for the first time in ,researches on ,light4 #aai 8,if a solution of peroxalate of iron be kept in a dark place1 or if it be exposed to #bab of ,fahr4 for several hours1 it does not undergo any sensible change in its physical properties1 nor does it exhibit any phenomenon which may be considered as the result of any elementary action4 8,if1 however1 it be exposed to the influence of solar light in a glass vessel provided with a tube1 the concentrated solution of oxalate of iron soon presents a very interesting phenomenon3 in a short time the solution receiving the solar rays1 developes an infinite number of bubbles of gas1 which rise in the liquor with increasing rapidity1 and give the solution the appearance of a syrup undergoing strong fermentation4 ,this ebullition always becomes stronger1 and almost tumultuous1 when an unpolished glass tube is immersed in it with a small piece of wood2 the liquid itself is afterwards thrown into ascending and descending currents1 becomes gradually yellowish1 turbid1 and eventually precipitates protoxalate of iron1 in the form of small brilliant crystals of a lemon-yellow colour1 gas continuing to evolve40 ,chemical action of light1 and formation of ,humboldtine by it2 ,phil4 ,mag41 #ahcb1 second series4--8,when a solution of platinum in nitro-muriatic acid1 in which the excess of acid has been neutralized by the addition of lime1 and which has been well cleared by filtration1 is mixed with lime-water in the dark1 no precipitation to any considerable extent takes place for a long while1--indeed1 none whatever1 though after very long standing a slight flocky sediment is formed1 after which the action is arrested entirely4 ,but if the mixture1 either freshly made or when cleared by subsidence of this sediment1 is exposed to sunshine1 it instantly becomes milky1 and a copious formation of a white precipitate 7or a pale yellow one1 if the platinic solution be in excess7 takes place1 which subsides quickly and is easily collected4 ,the same takes place more slowly in cloudy daylight40--,on the action of light in determining the precipitation of ,muriate of ,platinum by ,lime water2 being an extract from a letter from ,sir ,john ,f4 ,w4 ,herschel1 ,k4,h41 ,f4,r4,s41 c41 to ,dr4 ,daubeny4--,phil4 ,mag4 #ahcb4 #abj ,on a change produced by ,exposure to the ,beams of the ,sun1 in the properties of an elementary substance1 by ,professor ,draper2 ,on the changes which bodies undergo in the dark1 by ,robert ,hunt3 ,report of the ,thirteenth ,meeting of the ,british ,association1 vol4 xii1--,description of the ,tithonometer1 an instrument for measuring the chemical force of the ,indigo-tithonic rays3 by ,j4 ,w4 ,draper1 ,m4,d4--,philosophical ,magazine1 ,dec4 #ahdc1 vol4 xxiii4 #aba ,for several illustrations of this remarkable phenomenon1 see ,on the ,action of the ,rays of the ,solar ,spectrum on ,vegetable ,colours1 and on some new ,photographic ,processes2 by ,sir ,john ,f4 ,w4 ,herschel1 ,bart41 ,k4,h41 ,f4,r4,s4--,phil4 ,trans4 ,june1 #ahdb1 vol4 cxxxiii42 ,on certain improvements on ,photographic ,processes described in a former communication1 and on the ,parathermic ,rays of the ,solar ,spectrum2 by ,sir ,john ,f4 ,w4 ,herschel1 ,bart41 ,k4,h41 ,f4,r4,s41 c41 in a letter addressed to ,s4 ,hunter ,christie4--,phil4 ,trans4 #ahdc1 vol4 cxxxiv4 #abb ,sir ,j4 ,f4 ,w4 ,herschel2 see also ,researches on ,light1 by the ,author4 #abc ,attention has been directed to the protecting action of certain rays of the spectrum by ,sir ,john ,herschel and others4 ,see the ,eighteenth ,report of the ,british ,association for an experiment by the ,author1 in which it was proved that all the ,,light rays protected photographic papers from chemical change1 and1 therefore1 convincingly show that light and actinism were not similar powers4 #abd 8,having noticed1 one densely foggy day1 that the disc of the sun was of a deep red colour1 ,i directed my apparatus towards it4 ,after ten seconds of exposure1 ,i put the prepared plate in the mercury box1 and ,i obtained a round image perfectly black2--the sun had produced no photogenic effect4 ,in another experiment1 ,i left the plate operating for twenty minutes2 the sun had passed over a certain space of the plate1 and there resulted an image seven or eight times the sun's diameter in length2 it was black throughout1 so that it was evident1 wherever the red disc of the sun had passed1 not only was there a want of photogenic action1 but the red rays had destroyed the effect produced previous to the sun's passage4 ,i repeated these experiments during several days successively1 operating with a sun of different tints of red and yellow4 ,these different tints produced nearly the same effect2 wherever the sun had passed1 there existed a black band40--,mr4 ,claudet1 ,on different properties of ,solar ,radiation1 modified by coloured glass media1 c43 ,phil4 ,trans4 #ahdg4 ,part #b4 #abe 8,it may also be observed that the rays effective in destroying a given tint are1 in a great many cases1 those whose union produces a colour complementary to the tint destroyed1 or at least one belonging to that class of colours to which such complementary tint may be referred4 ,for example1 yellows tending towards orange are destroyed with more energy by the blue rays2 blue by the red1 orange1 and yellow rays2 purples and pinks by yellow and green rays40--,sir ,j4 ,f4 ,w4 ,herschel1 ,on the action of the rays of the ,solar ,spectrum on ,vegetable ,colours3 ,phil4 ,trans41 vol4 cxxxiii4 #ahdb4 #abf ,the following memoirs and works are necessary to a complete history of the inquiry3--,experiments and observations relating to various branches of natural philosophy1 with a continuation of the observation on air3 by ,dr4 ,priestley4 ,london1 #aggi4 ,mmoires ,physico-chimiques1 c43 by ,j4 ,senebier4 ,expriences sur les vgtaux1 by ,de la ,ville3 ,paris1 #aghb2 and ,phil4 ,trans4 #aghb4 ,observations sur les expriences de ,m4 ,ingenhousz3 by ,de la ,ville2 ,roz4 obs4 #bc1 #bij4 ,expriences propres dvelopper les effets de la lumire sur certaines plantes3 by ,tessier2 ,mm4 de l',ac4 des ,sc4 de ,paris1 #aghc1 p4 #acb2 ,licht4 ,mag4 iv4 #d1 #adf4 ,sur la vertu de l'eau impregne d'air fixe pour en obtenir1 par le moyen des plantes et de la lumire du soleil1 de l'air dphlogistiqu3 by ,ingenhousz2 ,roz4 obs4 #bd1 #ccg4 ,expriences sur l'action de la lumire solaire dans la vgtation3 by ,senebier2 ,genve et ,paris1 #aghh1 p4 #fa4 ,extrait des expriences de ,m4 ,senebier sur l'action de la lumire solaire dans la vgtation3 by ,hasenfratz2 ,ann4 ,chim4 iii4 #bnd4 ser4 #bff4 ,expriences relatives l'influence de la lumire sur quelques vgtaux3 by ,de ,candolle2 ,jour4 de ,ph4 lii4 #abd3 ,voigt's ,mag4 ii4 #dhc2 ,gilb4 ,ann4 xiii4 #cgb2 ,mm4 des ,sav4 ,etr4 i4 #cbi4 ,recherches chimiques sur la vgtation3 by ,saussure2 ,ann4 ,chim4 l4 #bbe2 ,jour4 de ,ph4 lvii4 p4 #cic2 ,gilb4 ,ann4 xviii #bjh4 ,recherches sur la respiration des plantes exposes la lumire du soleil2 by ,ruhland2 ,ann4 ,ch4 ,ph4 iii4 #daa2 ,jour4 de ,ph4 #ahaf4 ,on the action of light upon plants1 and of plants upon the atmosphere3 by ,dr4 ,daubeny2 ,phil4 ,trans4 cxxvii ,january1 #ahcf4 ,on the action of yellow light in producing the green colour1 and of indigo light on the movements of plants3 by ,p4 ,gardner2 ,phil4 ,mag4 xxiv42 ,bibl4 ,univ4 xlix4 p4 #cgf1 and lii4 p4 #cha4 ,on the influence of light on plants3 by ,r4 ,hunt2 ,phil4 ,mag4 xxiv4 p4 #if2 ,bibl4 ,univ4 xlix4 p4 #chc2 ,athen4 #ahdd4 ,note on the decomposition of carbonic acid by the leaves of plants1 under the influence of yellow light3 by ,draper2 ,phil4 ,mag4 xxv4 p4 #afi4 ,on the action of the yellow rays of light on vegetation3 by ,harkness2 ,phil4 ,mag4 xxv4 p4 #cci4 ,influence des rayons solaires sur la vgtation3 by ,zantedeschi2 ,inst4 ,no4 #eda1 p4 #aeg4 #abg ,sir ,john ,herschel's ,memoirs already referred to2 and ,reports on the influence of the ,solar ,rays on the growth of ,plants1 by ,robert ,hunt3 ,report of the ,british ,association for the ,advancement of ,science1 for #ahdg4 #abh ,memoir on the ,constitution of the ,solar ,spectrum1 presented at the meeting of the ,academy of ,sciences1 #ahdb1 by ,m4 ,edmond ,becquerel2 ,des effets produits sur les corps par les rayons solaires1 par ,m4 ,edmond ,becquerel1 aide au ,musum d',histoire ,naturelle3 ,mmoire prsent l',acadmie des ,sciences1 le #bc ,octobre1 #ahdc4--8;,dans le courant de ce mmoire1 j'ai employ les noms de rayons lumineux1 chimiques1 et phosphorogniques1 pour dsigner1 dans chaque cas1 la portion des rayons solaires qui agit pour produire1 en particulier1 les effets lumineux1 chimiques1 et phosphorogniques2 mais cela est sans prjudice de l'opinion que je viens d'mettre touchant l'existence d'un seul et mme rayonnement40 8,my reply is this10 says ,m4 ,arago1 in his paper entitled ,considerations relative to the action of ,light3 8,it is by no means proved that the photogenic modifications of sensitive substances result from the action of the solar light itself4 ,the modifications are1 perhaps1 engendered by invisible radiations mixed with light properly so called1 proceeding with it1 and being similarly refracted4 ,in this case1 the experiment would prove not only that the spectrum formed by these invisible rays is not continuous1 that there are solutions of continuity as in the visible spectrum1 but also that in the two superposed spectra these solutions correspond exactly4 ,this would be one of the most curious1 one of the most strange results of physics40--,taylor's ,scientific ,memoirs4 #abi ,the chemical evidence of this will be found in ,sir ,john ,herschel's ,memoir ,on the ,solar ,spectrum1 and particularly as exemplified in the changes produced on the tartrate of silver4 ,similar influences are described as observed on a ,daguerreotype plate1 in a paper entitled ,experiments and ,observations on ,light which has permeated coloured media1 and on the ,chemical ,action of the ,solar ,spectrum2 by ,robert ,hunt4--,philosophical ,magazine1 vol4 xxvi4 #ahdj4 #acj ,this peculiar continuance of an effect has frequently been observed in many of the photographic processes4 ,in a note to a memoir ,on certain improvements in ,photographic processes1 ,sir ,john ,herschel thus refers to this property3--8,the excitement is produced on such paper by the ordinary moisture of the atmosphere1 and goes on slowly working its effect in the dark1 apparently without other limit than is afforded by the supply of ingredients present4 ,in the case of silver it ultimately produces a perfect silvering of all the sunned portions4 ,very singular and beautiful photographs1 having much resemblance to ,daguerreotype pictures1 are thus produced2 the negative character changing by keeping1 and by quite insensible gradations to positive1 and the shades exhibiting a most singular chatoyant change of colour from ruddy-brown to black1 when held more or less obliquely4 ,no doubt1 also1 gold pictures with the metallic lustre might be obtained by the same process1 though ,i have not tried the experiment40 #aca ,the details of this curious subject may be studied in the following memoir and communications3--,on vision and the action of light on all bodies3 by ,professor ,ludwig ,moser1 of ,knigsberg2 from ,poggendorff's ,annalen1 vol4 lvi4 p4 #agg1 ,no4 #f1 #ahde4 ,some remarks on ,invisible ,light3 by ,professor ,ludwig ,moser1 of ,knigsberg2 from ,poggendorff's ,annalen1 vol4 lvi4 p4 #efi1 ,no4 #h4 ,on the power which light possesses of becoming latent3 by ,professor ,ludwig ,moser1 of ,knigsberg2 from ,poggendorff's ,annalen1 vol4 lvii4 ,no4 #i1 p4 #a4 #ahdb4 ,on certain spectral appearances1 and on the discovery of latent light3 by ,j4 ,w4 ,draper1 ,m4,d41 ,professor of ,chemistry in the ,university of ,new ,york2 ,phil4 ,mag4 p4 #cdh1 ,nov4 #ahdb4 ,on a new imponderable substance1 and on a class of chemical rays analogous to the rays of dark heat3 by ,professor ,draper2 ,phil4 ,mag41 ,dec4 #ahdb4 ,on the action of the rays of the solar spectrum on the ,daguerreotype plate2 by ,sir ,j4 ,f4 ,w4 ,herschel1 ,bart42 ,phil4 ,mag41 ,feb4 #ahdc4 ,see remarks in this paper on the use which ,moser has made of coloured glasses3 also a communication by ,professor ,draper1 ,on the rapid ,detithonizing power of certain gases and vapours1 and on an instantaneous means of producing spectral appearances3 ,phil4 ,mag41 ,march #ahdc2 and ,on the causes which concur in the production of the images of ,moser3 ,comptes ,rendus1 ,nov4 #ahdb4 ,see ,scientific ,memoirs1 vol4 iii4 #acb ,this fact was first observed by myself1 and described in the paper already referred to1 ,philosophical ,magazine1 vol4 xxii4 p4 #bgj4 ,it does not1 however1 appear to have attracted the attention of any other observer4 #acc ,on ,thermography1 or the ,art of copying ,engravings or any printed characters from paper or plates of metal1 and on the recent discovery of ,moser1 relative to the formation of images in the dark1 by ,robert ,hunt3 ,reports of the ,royal ,cornwall ,polytechnic ,society for #ahdb1 and ,philosophical ,magazine1 vol4 xxi4 p4 #dfb4--,on the ,spectral ,images of ,m4 ,moser1 by ,robert ,hunt3 ,philosophical ,magazine1 vol4 xxiii4 p4 #dae4 #acd ,catalytic force1 or attraction of surface concerned in the diffusive power of gases3 an occult energy or power in saturated saline solutions2 ,prater4--,mechanic's ,magazine1 vol4 xlv4 p4 #ajf4 ,ueber elektrische ,abbildungen2 by ,g4 ,karsten4--,poggendorff's ,annalen1 vol4 lvii4 p4 #djb4--,melloni and ,brewster may be consulted for much that is most remarkable connected with radiation from coloured surfaces4 #ace ,cornelius ,agrippa is said to have possessed such a mirror4 ,the ,chinese make mirrors which1 when placed in a particular light1 show upon their polished faces the pattern on the back of the metal1 although it is invisible in every other position4 ,this is effected by giving different degrees of hardness to the various parts of the metal4 ,in ,natural ,magic1 by ,sir ,david ,brewster1 several curious experiments belonging to this class are named4 ,,chapter ,,ix4 ,,electricity4 ,discovery of ,electrical ,force--,diffused through all ,matter--,what is ,electricity8--,theories--,frictional ,electricity--,conducting ,power of ,bodies--,hypothesis of two ,fluids--,electrical ,images--,galvanic ,electricity--,effects on ,animals--,chemistry of ,galvanic ,battery--,electricity of a ,drop of ,water--,electro-chemical ,action--,electrical ,currents--,thermo-,electricity--,animal ,electricity--,gymnotus--,torpedo--,atmo spheric ,electricity--,lightning ,conductors--,earth's ,magnetism due to ,electrical ,currents--,influence on ,vitality--,animal and ,vegetable ,development--,terrestrial ,currents--,electricity of ,mineral ,veins--,electrotype--,influence of ,heat1 ,light1 and ,actinism on ,electrical ,phenomena4 ,if a piece of amber1 electrum1 is briskly rubbed1 it acquires the property of attracting light bodies4 ,this curious power excited the attention of ,thales of ,miletus2 and from the investigations of this ,grecian philosopher we must date our knowledge of one of the most important of the natural forces--,electricity4 ,if an inquiring mind had not been led to ask why does this curious natural production attract a feather1 the present age1 in all probability1 would not have been in possession of the means by which it is enabled to transmit intelligence with a rapidity which equals the poet's dream of the 8swift-winged messengers of thought40 ,to this age of application a striking lesson does this amber teach4 ,modern utility would have regarded ,thales as a madman4 ,holding a piece of yellow resin in his hand1 rubbing it1 and then picking up bits of down1 or catching floating feathers1 the old ,greek would have appeared a very imbecile1 and the cui bono generation would have laughed at his silly labours4 ,but when he announced to his school that this amber held a soul or essence1 which was awakened by friction1 and went forth from the body in which it previously lay dormant1 and brought back the small particles floating around it1 he gave to the world the first hint of a great truth which has advanced our knowledge of physical phenomena in a marvellous manner1 and ministered to the refinements and to the necessities of civilisation4 ,each phenomenon which presents itself to us1 however simple it may appear to be1 is an outward expression of some internal truth1 the interpretation of which is only to be arrived at by assiduous study1 but which1 once discovered1 directs the way to new knowledge1 and gives to man a great increase of power4 ,there is no truth so abstract that it will not find its useful application1 and every example of the ministration of ,physical ,science to the purposes of humanity is an evidence of the value of abstract study1 and a reply to the utilitarian in his own language4 ,electricity appears to be diffused through all nature2 and it is1 beyond all doubt1 one of the most important of the physical forces1 in the great phenomena of creation4 ,in the thunder-cloud1 swelling with destruction1 it resides1 ready to launch its darts and shake the earth with its explosions3 in the arial undulations1 silent and unseen1 it passes1 giving the necessary excitement to the organisms around which it floats4 ,the rain-drop--the earth-girdling ocean--and the ringing waters of the hill-born river1 hold locked this mighty force4 ,the solid rocks--the tenacious clays which rest upon them--the superficial soils--and the incoherent sands1 give us evidence of the presence of this agency2 and in the organic world1 whether animal or vegetable1 the excitement of electrical force is always to be detected4 ,in the solar radiations we have perhaps the prime mover of this power4 ,in our atmosphere1 when calm and cloudless1 a great ocean of light1 or when sombre with the mighty aspect of the dire tornado1 we can constantly detect the struggle between the elements of matter to maintain an equilibrium of electrical force4 ,diffused throughout matter1 electricity is ever active2 but it must be remembered that although it is evidently a necessary agent in all the operations of nature1 that it is not the agent to which everything unknown is to be referred4 ,doubtless the influence of this force is more extensive than we have yet discovered2 but that is an indolent philosophy which refers1 without examination1 every mysterious phenomenon to the influence of electricity4 ,the question1 what is electricity8 has ever perplexed1 and still continues to agitate1 the world of science4 ,while one set of experimentalists have endeavoured to explain the phenomena they have witnessed1 upon the theory that electricity is a peculiar subtile fluid pervading matter1 and possessing singular powers of attraction and repulsion1 another party find themselves compelled to regard the phenomena as giving evidence of the action of two fluids which are always in opposite states2 while again1 electricity has been considered by others as1 like the attraction of gravitation1 a mere property of matter4#acf ,certain it is1 that in the manifestations of electrical phenomena we have1 as it appears1 the evidence of two conditions of force2 but of the states of positive or negative1 of vitreous or resinous electricity1 we have a familiar explanation in the assumption of some current flowing into or out of the material body1--of some principle which is ever active in maintaining its equilibrium1 which1 consequently1 must act in two directions1 and always exhibit that duality which is a striking characteristic of this subtile agent4 ,it is a curious1 and it should be an instructive fact1 that each of the three theories of electricity is capable of proof1 and has1 indeed1 been most ably supported by the rigorous analysis of mathematics4 ,when we remember that some of the most enlightened investigators of this and the past age have severally maintained1 in the most able manner1 these dissimilar views1 we should hesitate before we pronounce an opinion upon the cause or causes of the very complicated phenomena of electrical force4 ,although we discover1 in all the processes of nature1 the manifestations of this principle or force in its characteristic conditions1 it will be necessary1 before we regard the great phenomena1 to examine the known sources from which we can most readily evoke the mighty power of electricity4 ,if we rub a piece of glass or resin1 we readily render this agent active2 these substances appear1 by this excitement1 to become surrounded by an attractive or a repellent atmosphere4 ,let us rub a strip of writing paper with ,indian rubber1 or a strip of ,gutta ,percha with the fingers1 in the dark1 and we have the manifestation of several curious phenomena4 ,we have a peculiar attracting power2 we have a luminous discharge in the shape of a spark2 and we have very sensible evidence of muscular disturbance produced by applying the knuckle to the surface of the material4 ,in each case we have the development of the same power4 ,every substance in nature is an electric1 and1 if so disposed that its electricity may not fly off as it is developed1 we may1 by friction1 manifest its presence1 and1 indeed1 measure its quantity or its force4 ,all bodies are not1 however1 equally good electrics2 shell-lac1 amber1 resins1 sulphur1 and glass1 exhibiting more powerfully the phenomena of frictional or mechanical electricity1 than the metals1 charcoal1 or plumbago4 ,solid bodies allow this peculiar principle to pass along them also in very different degrees4 ,thus electricity travels readily through copper and most other metals1 platinum being the worst metallic conductor4 ,it also passes through living animals and vegetables1 smoke1 vapour1 rarified air1 and moist earth2 but it is obstructed by resins and glass1 paper when dry1 oils1 and dry metallic oxides1 and in a very powerful manner by ,gutta ,percha4#acg ,if1 therefore1 we place an electric upon any of those non-conducting bodies1 the air around being well dried1 we are enabled to gather a large quantity of the force for the production of any particular effect4 ,taking advantage of this fact1 arrangements are made for the accumulation and liberation at pleasure of any amount of electricity4 ,a ,leyden phial1--so called from its inventor1 ,musschenbroek1 having resided at ,leyden1--is merely a glass bottle lined within and without1 to within a few inches of the top1 with a metal coating4 ,if a wire or chain1 carrying an electric current1 is allowed to dip to the bottom of the bottle1 the inner coat of the jar becomes charged1 or gathers an excess1 whilst the outer one is in its natural condition--one is said to be in a positive1 and the other in a negative state4 ,if the two coatings are now connected by a good conductor1 as a piece of copper wire1 passing from one to the other1 the outside to the inside1 a discharge1 arising from the establishment of the equilibrium of the two coatings1 takes place2 and1 if the connection is made through the medium of our bodies1 we are sensible of a severe disturbance of the nervous system4 ,the cause of the conducting and non-conducting powers of bodies we know not2 they bear some relation to their conducting powers for caloric2 but they are not in exact obedience to the same laws4 ,when we consider that resin1 a comparatively soft body1 in which1 consequently1 cohesive attraction is not very strong1 is an imperfect conductor1 and that copper1 in which cohesion is much more powerful1 is a good conductor1 we may be disposed to consider that it is regulated by the closer approximation of the particles of matter4 ,but in platinum the corpuscular arrangement must be much more dense than it is in copper1 and yet it is1 compared with it1 a very bad conductor4#ach ,we have now learnt that we may1 by friction1 excite the electricity in a vitreous substance2 but it must not be forgotten that we cannot increase the quantity which is1 under ordinary conditions1 natural to the electric2 to do so1 we must in some way establish a channel of communication with the earth1 from which1 through the medium we excite1 we draw our supply4 ,we have the means of confining this mighty force within certain limits of quantity and of time4 ,if we place bodies which are susceptible of electrical excitation in a sensible degree upon insulating ones1 we may retain for a considerable time the evidences of the excitement1 in the same way as with the ,leyden jar2 but there is a constant effort to maintain a balance of conditions1 and the body in which we have accumulated any extraordinary quantity by conduction soon returns to its natural state4 ,a very simple means may be adopted of showing what is thought to be one of the many evidences in favour of two electricities4 ,if the wire carrying the current flowing from the machine1 is passed over paper covered with nitrate of silver1 it produces no change upon it2 but if the wire which conveys the current to the instrument1 when it is excited1 is passed over the same paper1 the silver salt is decomposed4#aci ,we may1 however1 explain this result in a satisfactory manner1 upon the hypothesis that the decomposition is produced by the abstraction of electricity1 rather than by any physical difference in the fluid itself4 ,by frictional electricity we may produce curious molecular disturbances1 and give rise to molecular re-arrangements1 which have been called 8electrical images10 in glass1 in stone1 and in the apparently less tractable metals3 these images are rendered visible by the manner in which1 according to their electrical states1 some lines receive any particular powder1 or vapour1 which is repelled from other spaces4 ,many of the great natural phenomena1 such as ,lightning and ,thunder1 the ,aurora ,borealis1 and ,meteors1 may be imitated in a curiously exact manner by the electrical machine and a few familiar arrangements4#adj ,voltaic electricity1 as the active force produced by chemical change is commonly called1 in honour of the illustrious ,volta1 is now to be considered4 ,it differs from frictional electricity in this3--the electricity developed by friction of the glass plate or cylinder of the electrical machine is a discharge with a sort of explosion4 ,it is electricity suddenly liberated from the highest state of tension1 whereas that which is generated by chemical action in the voltaic battery is a steady flowing current4 ,we may compare one to the ignition of a mass of gunpowder at once1 and the other to the slow burning of the same quantity spread out into a very prolonged train4 ,there are numerous ways in which we may excite the phenomena of ,voltaism1 but in all of them the decomposition of one of the elements employed appears to be necessary4 ,this is the case in the arrangements of batteries in which two dissimilar metals1 zinc and copper1 silver and platinum1 or the like1 is immersed in fluids2 the zinc or the silver are gradually converted into soluble salts1 which are dissolved1 whilst the copper or platinum is protected from any action4 ,the most simple manner of illustrating the development of this electricity is by placing a piece of silver on the tongue1 and a piece of zinc or lead underneath it4 ,no effect will be observed so long as the two metals are kept asunder1 but when their edges are brought together1 a slight tremulous sensation will pass through the tongue1 a saline taste be distinguished by the palate1 and if in the dark1 light will be observed by the eye4 ,this1 the germ of the most remarkable of the sciences1 was noticed by ,sulzar1 fifty years before ,galvani observed the convulsions in the limbs of frogs1 when excited by the action of dissimilar metals2 but the former paid little attention to the phenomenon1 and the discovery led to no results4 ,when ,galvani's observant mind was directed to the remarkable fact that the mere contact of two dissimilar metals with the moist surface of living muscles produced convulsions1 there was an awakening in the soul of that philosopher to a great fundamental truth1 which was nurtured by him1 tried and tested1 and preserved to work its marvels for future ages4 ,although the world of science looks back to ,volta as the man who gave the first true interpretation of this discovery1 yet the ordinary world will never disconnect this important branch of physical science from the name of ,galvani1 and chemical electricity in all its forms will for ever be known under the familiar name of ,galvanism4 ,and it must not be forgotten1 that the phenomena of the manifestation of electricity1 in connection with the conditions of vitality1 are entirely due to ,galvani4 ,let us examine the phenomena of ,galvanism in its most simple phases3-- ,if we place a live flounder upon a plate of zinc1 put a shilling on its back1 and then touch both metals with the ends of a metallic wire1 the fish will exhibit painful convulsions4 ,the zinc becomes oxidized by the separation of oxygen from the fluid on the surface with which it is in contact1 whilst hydrogen gas is liberated at that surface touched by the other metal4 ,here we have1 in the first place1 a chemical change effected1 then a peculiar muscular disturbance4 ,each successive combination or decomposition1 like a pulsation1 is transmitted along the circuit from one extremity to the other4 ,how the impulse which is derived from the zinc is transmitted through the body of the animal1 or the tongue1 to the silver or copper is the next consideration4 ,we can only understand this upon the supposition that a series of impulses are communicated in the most rapid manner along the connecting line2 the idea of a current1 although the term is commonly employed1 tends to convey an imperfect impression to the mind4 ,it would seem rather that a disturbance throughout the entire circuit is at once set up by a series of vibrations or impulses communicated from particle to particle1 and along the strange net-work of nerves4 ,one set of chemical elements have a tendency to develope themselves at that point where vibration is first communicated to the mass from a better conductor than it is1 and another set at the point where it passes from the body to a better conductor than itself4 ,the cause of this is to be sought for in the laws which regulate molecular constitution--by which chemical affinity is disturbed1--and a new attractive force exerted1 in obedience to which the vital energy is itself agitated4 ,we must not1 however1 forget that it is probable after all1 although not yet susceptible of proof1 that the electricity does nothing more than disturb or quicken the unknown principles upon which chemical and vital phenomena depend2 being1 indeed1 a secondary agent4#ada ,notwithstanding our long acquaintance with the phenomena of galvanism1 there are but few who entertain a correct idea of the enormous amount of electricity which is necessary to the existing conditions of matter4 ,to ,faraday we are indebted for the first clear set of deductions from a series of inductive researches1 which are of the most complete order4 ,he has proved1 by a series of exceedingly conclusive experiments1 that if the electrical power which holds a grain of water in combination1 or which causes a grain of oxygen and hydrogen to unite in the right proportions to form water1 could be collected and thrown into the condition of a voltaic current1 it would be exactly the quantity required to produce the decomposition of that grain of water1 or the liberation of its elements1 hydrogen and oxygen4#adb ,by direct experiment it has been proved that one equivalent of zinc in a voltaic arrangement evolves such a quantity of electricity in the form of a current1 as1 passing through water1 will decompose exactly one equivalent of that fluid4 ,the law has been thus expressed3--,the electricity which decomposes1 and that which is evolved by the decomposition of a certain quantity of matter1 are alike4 ,the equivalent weights of bodies are those quantities of them which contain equal quantities of electricity2 electricity determining the equivalent number1 because it determines the combining force4#adc ,the same elegant and correct experimentalist has shown that zinc and platinum wires1 one-eighteenth of an inch in diameter1 and about half an inch long1 dipped into water in which is mixed sulphuric acid so weak that it is not sensibly sour to the tongue1 will evolve more electricity in one-twentieth of a minute than is given by thirty turns of a large and powerful plate electrical machine in full action1 a quantity which1 if passed through the head of a cat1 is sufficient to kill it as by a flash of lightning4 ,pursuing this interesting inquiry yet further1 it is found that a single grain of water contains as much electricity as could be accumulated in #hjj1jjj ,leyden jars1 each requiring thirty turns of the large machine of the ,royal ,institution to charge it1--a quantity equal to that which is developed from a charged thunder-cloud4 8,yet we have it under perfect command1--can evolve1 direct1 and employ it at pleasure2 and when it has performed its full work of electrolisation1 it has only separated the elements of a single grain of water40 ,it has been argued by many that the realities of science will not admit of anything like a poetic view without degrading its high office2 that poetry1 being the imaginative side of nature1 has nothing in common with the facts of experimental research1 or with the philosophy which generalises the discoveries of severe induction4 ,if our science was perfect1 and laid bare to our senses all the secrets of the inner world2 if our philosophy was infallible1 and always connected one fact with another through a long series up to the undoubted cause of all--then poetry1 in the sense we now use the term1 would have little business with the truth2 it would1 indeed1 be lost or embodied1 like the stars of heaven1 in the brightness of a meridian sun4 ,but to take our present fact as an example1 how important a foundation does it offer upon which to build a series of thoughts1 capable of lifting the human mind above the materialities by which it is surrounded1--of exalting each common nature by the refinement of its fresh ideas to a point higher in the scale of intelligence1--of quickening every impulse of the soul1--and of giving to mankind the most holy longings4 ,what does science tell us of the drop of water8 ,two gases1 the one exciting life and quickening combustion1 the other a highly inflammable air1 are1 by the influence of a combination of powers1 brought into a liquid globe4 ,we can1 from this crystal sphere1 evoke heat1 light1 electricity1 and actinism in enormous quantities2 and beyond these we can see powers or forces1 for which1 in the poverty of our ideas and our words1 we have not names2 and we learn that each one of these principles is engaged in maintaining the conditions of the drop of water which refreshes organic nature1 and gives gladness to man's dwelling-place4 ,has poetry a nobler theme than this8 ,agencies are seen like winged spirits of infinite power1 each one working in its own peculiar way1 and all to a common end1--to produce1 under the guidance of omnipotent rule1 the waters of the rivers and the seas4 ,as the great ocean mirrors the bright heaven which overspreads it1 and reflects back the sunlight and the sheen of the midnight stars in grandeur and loveliness2 so every drop of water1 viewed with the knowledge which science has given to us1 sends back to the mind reflections of yet distant truths which1 rightly followed1 will lead us upwards and onwards in the tract of higher intelligences1-- 8,to the abodes where the eternals are40 ,in the discoveries connected with electricity1 we have results of a more tangible character than are as yet connected with the other physical forces2 and it does appear that this science has advanced our knowledge of nature and of the mysteries of creation far more extensively than any other department of purely experimental inquiry4 ,the phenomena of electro-chemical action are so strange that we must return for a moment to the consideration of the decomposition of water1 and the appearance of hydrogen at one pole1 and of oxygen at the other4 ,it appears that some confusion of our ideas has arisen from the views which have been received of the atomic constitution of bodies4 ,we have been accustomed to regard water1--to take that body as an example of all1--as a compound of two gases1 hydrogen and oxygen2 an equivalent1 or one atom of the first1 united to an equivalent or one atom of the last1 forming one atom of water4 ,this atom of water we regard as infinitely small2 consequently a drop of water is made up of many hundreds of these combined atoms1 and a pint of water of not less than #aj1jjj drops4 ,now1 if this pint of water is connected with the wires of a galvanic battery1 although their extremities may be some inches apart1 for every atom of oxygen liberated at one pole1 an atom of hydrogen is set free at the other4 ,it has been thought that an atom has undergone decomposition at one point1 its oxygen being torn from it1 and then there has arisen the difficulty of sending the atom of hydrogen through all the combined atoms of water across to the other pole4 ,a series of decompositions and recompositions have been supposed to take place1 and the communication of effects from particle to particle4 ,an attracting power for one class of bodies has been found in one pole1 which is repellent to another class2 and the reverse order has been detected at the opposite pole of a galvanic arrangement4#add ,that is1 the wire which carries the current from an excited zinc plate has a relation to all bodies1 which is directly opposite to that which is exhibited by the wire conveying the current from1 or completing the circuit with1 the copper plate4 ,the one1 for instance1 collects and carries acids and the like1 the other the metallic bases4 ,at the extremity of one galvanic wire1 placed into a drop of water1 oxygen is always liberated2 and at the end of the other1 necessary to complete the circuit with the battery1 hydrogen is set free4 ,it appears necessary1 to a clear understanding of what takes place in this experiment1 that we should regard each mass1 howsoever large1 as the representative of a single atom4 ,nor is this difficult1 as the following illustration will show4 ,let us take one particle of common salt 7chloride of sodium7 weighing less than a grain1 and put it into a hundred thousand grains of distilled water4 ,in a few minutes the salt has diffused itself through the whole of the fluid1 and in every drop we can detect chlorine and soda4 ,we cannot believe that this grain of salt has split itself up into a hundred thousand parts2 we conceive rather that the phenomenon of solution is one of diffusion4 ,one infinitely elastic body has interpenetrated with another4 ,instead of an experiment with a pint of water1 let us take our stand on ,dover heights1 and1 with a gigantic battery at our command1 place one wire into the ocean on our own shores1 and convey the other through the air across the channel1 and let its extremity dip into the sea off ,calais pier--the experiment is a practicable one--we have now an electrical circuit of which the ,british channel forms a part1 and the result will be exactly the same as that which we may observe in a watch-glass with a drop of water4 ,we cannot suppose that the instantaneous and simultaneous effect which takes place in the water at ,calais and at ,dover1 is due to anything like what we have studied under the name of convection1 when considering ,heat4 ,a thousand balls are placed in a line touching each other2 the first ball receives a blow1 and the last ball flies off with a force exactly equal to the power applied to the first2 none of the intermediate balls being moved4 ,we cannot conceive that the particle ,a excites the particle ,b next it1 and so on through the series between the two shores2 but regarding the channel as one large drop1 charged with the electric principle as we know it to be1 it is excited by undulation or tremor throughout its width1 and we have an equivalent of oxygen thrown off on one side of the line1 and an exact equivalent of hydrogen at the other1 the electro-chemical influence being exerted only where the current or motion is transferred from one medium to another4#ade ,the imperfect character of this view is freely admitted2 no other1 consistent with known facts1 presents itself by which the effect can be explained4 ,the fact stands as a truth2 the hypothesis by which it is attempted to be interpreted is open to doubt1 and it is opposed to some favourite theories4 ,before we pass to the consideration of the other sources of electricity1 it is important we should understand that no chemical or physical change1 however slight it may be1 can occur without the development of electrical power4 ,if we dissolve a salt in water1 if we mix two fluids together1 if we condense a gas1 or convert a fluid into vapour1 electricity is disturbed1 and may be made manifest to our senses4#adf ,it has been shown that this power may be excited by friction 7machine electricity7 and by chemical action 7voltaic electricity1 galvanism72 it now remains to speak of the electricity developed by heat 7thermo-electricity71 the electricity exhibited under nervous excitement by the gymnotus and torpedo 7animal electricity72 magnetism and its phenomena being reserved for a separate consideration4 ,if a bar of metal is warmed at one end and kept cool at the other1 an electrical current circulates through the bar1 and may be carried off by connection with any good conductor1 and shown to exhibit the properties of ordinary electricity4 ,the metals best suited for showing the effects of thermo-electricity appear to be bismuth and antimony4 ,by binding two bars of these metals together at one end1 and connecting the other ends with a galvanometer1 it will be discovered that an electric current passes off through the instrument by the slightest variation of temperature4 ,merely clasping the two metals1 where bound together1 with the finger and thumb1 is sufficient to exhibit the phenomenon4 ,by a series of such arrangements1--which form what have been called thermo-electric multipliers1--we obtain the most delicate measurers of heat with which philosophers are acquainted1 by the aid of which ,melloni has been enabled to pursue his beautiful researches on radiant caloric4 ,that this electricity is identical with the other forms has been proved by employing the current thus excited for the purpose of producing chemical decomposition1 magnetism1 and electric light4#adg ,the phenomenon of thermo-electricity--the discovery of ,seebeck1 is another proof of the very close connection of the physical forces4 ,we witness their being resolved as it were into each other1 electricity producing heat1 and heat again electricity2 and it is from these curious results that the arguments in favour of their intimate relations and actual identity have been drawn4 ,it will1 however1 be found to be the best philosophy to regard these forces as dissimilar1 until we are enabled to prove them to be only modified forms of one principle or power4 ,at the same time it must not be forgotten that in natural operations we invariably find the combined action of several forces producing a single phenomenon4 ,the important fact to be particularly regarded is1 that we have evidence that every substance which is unequally heated becomes the source of this very remarkable form of electricity4#adh ,there exist a few fishes gifted with the very extraordinary power of producing electrical phenomena by an effort of muscular or nervous energy4 ,the ,gymnotus electricus1 or electrical eel1 and the ,raia torpedo1 a species of ray1 are the most remarkable4 ,this power is1 it would appear1 given to these curious creatures for purposes of defence1 and also for enabling them to secure their prey4 ,the ,gymnotus of the ,south ,america rivers1 will1 it is said1 when in full vigour1 send forth a discharge of electricity sufficiently powerful to knock down a man1 or to stun a horse2 while it can destroy fishes1 through a considerable space1 by exerting its strange artillery4#adi ,faraday's description of a ,gymnotus1 paralyzing and seizing its prey1 is too graphic and important to be omitted4 8,the ,gymnotus can stun and kill fish which are in very various positions to its own body2 but on one day1 when ,i saw it eat1 its action seemed to me to be peculiar4 ,a live fish1 about five inches in length1 caught not half a minute before1 was dropped into the tub4 ,the ,gymnotus instantly turned round in such a manner as to form a coil1 inclosing the fish1 the latter representing a diameter across it2 a shock passed1 and there1 in an instant1 was the fish struck motionless1 as if by lightning1 in the midst of the waters1 its side floating to the light4 ,the ,gymnotus made a turn or two to look for its prey1 which1 having found1 he bolted1 and then went about searching for more4 ,a second smaller fish was given him1 which being hurt in the conveyance1 showed but little signs of life1 and this he swallowed at once1 apparently without shocking it4 ,the coiling of the ,gymnotus round its prey had1 in this case1 every appearance of being intentional on its part1 to increase the force of the shock1 and the action is evidently well suited for that purpose1 being in full accordance with the well-known laws of the discharge of currents in masses of conducting matter2 and though the fish may not always put this artifice in practice1 it is very probable he is aware of its advantages1 and may resort to it in cases of need40#aej ,animal electricity has been proved to be of the same character as that derived from other sources4 ,the shock and the spark are like those of the machine2 and the current from the animal1 circulating around soft iron1 like galvanic electricity1 has the property of rendering it magnetic4 ,it is important that we should now review these conditions of electrical force in connexion with the great physical phenomena of nature4 ,it is sufficiently evident1 from the results which have been examined1 that all matter1 whatever may be its form or condition1 is for ever under the operation of the physical forces1 in a state of disturbance4 ,from the centre to the surface all is in an active condition3 a state of mutation prevails with every created thing2 and science clearly shows that influences are constantly in action which prevent the possibility of absolute repose4 ,under the excitement of the several agencies of the solar beams1 motion is given to all bodies by the circulation of heat1 and a full flow of electricity is sent around the earth to perform its wondrous works4 ,the solar influences1 which regulate1 and possibly determine1 every physical force with which we are acquainted1 are active in effecting an actual change of state in matter4 ,the sunbeam of the morning falls on the solid earth1 and its influence is felt to the very centre4 ,the mountain-top catches the first ray of light1 and its base1 still wrapt in mists and darkness1 is disturbed by the irradiating power4 ,the crystalline gems1 hidden in the darkness of the solid rock1 are dependent1 for that form which makes them valued by the proud and gay1 on the influence of those radiations which they are one day to refract in beauty4 ,the metals locked in the chasms of the rifted rocks are1 for all their physical peculiarities1 as dependent on solar influence as is the flower which lifts its head to the morning sun1 or the bird which sings 8at heaven's high gate40 ,let us1 then1 examine how far electricity1 as distinguished from the other powers1 acts in producing any of these effects4 ,we find electricity in the atmosphere1 which the electrical kite of ,dr4 ,franklin proved to be identical with that principle produced by the friction of glass4 ,in the grandeur and terror of a thunderstorm1 many see nothing but manifestations of ,almighty wrath4 ,when the volleys of the bursting cloud are piercing the disturbed air1 and the thunders of the discharge are pealing their dreadful notes above our heads1 the chemical combinations of the noxious exhalations arising from the putrefying animal and vegetable masses of this earth are effected1 elements fitted for the purposes of health and vegetation are formed1 and brought to the ground in the heavy rains which usually follow these storms4 ,science has taught man this--has shown him that the 8partial evil0 arising from the 8winged bolt0 is a 8universal good20 and1 more than this1 it has armed him with the means of protecting his life and property from the influence of lightnings4 ,so that1 like ,ajax1 he can defy the storm4 ,by metallic rods1 carried up a chimney1 a tower1 or a mast1 we may form a channel through which the whole of the electricity of the most terrific thunder-cloud may be carried harmlessly into the earth or the sea2 and it is pleasing to observe that at length prejudice has been overcome1 and 8conductors0 are generally attached to high buildings1 and to most of the ships of our navy4#aea ,it was discovered that the devastating hailstorms of the south of ,france and ,switzerland1 so destructive to the vineyards and crops1 were accompanied by evidences of great electrical excitation1 and it was proposed to discharge the electricity from the air by means of pointed metallic rods4 ,these have been adopted1 and1 it is said1 with real advantage--each rod protecting an area of one hundred yards4 ,thus it is that science ministers to our service2 and how much more pleasing is it to contemplate the lightning1 with the philosopher1 as an agent destroying the elements of pestilence1 and restoring the healthfulness of the air we breathe1 than with the romancer1 to see in it only the dreaded aspect of a demon of destruction4 ,the laws which regulate the spread of a pestilence are unknown4 ,the difficulties of the investigation are great1 but they are by no means insurmountable4 ,a plague passes from the east to the west across the world--it spreads mourning over the gayest cities1 and sorrow sitteth in the streets4 ,the black death rises in the ,orient3 it goes on in unchecked strength1 and only finishes its course when it has made the circuit of the civilized world4 ,the cholera spreads its ebon wings--mankind trembles--watches its progress1 and looks upon the path which is marked by the myriads of the dead1 who have fallen before the dire fiend4 ,the diseases pass away--the dead are buried1 and all is forgotten4 ,the rush and the riot of life are pursued3 and until man is threatened with another advent1 he cares not to trouble himself4 ,accompanying the last visitation1 there appear certain peculiar meteorological conditions1 which point a line of inquiry4 ,it may or may not be the path which leads to the truth1 but certainly its indications are worthy of careful examination4 ,it may be asked1 can weak man stop a pestilence2 can a mortal's puny hand retard the afflictions of the ,almighty8 ,the question asked--it must be answered in reverence1 yet without fear4 ,no human power can produce a change in the physical conditions of the earth1 or of the air2 and if our diseases are connected with those changes1 as beyond all doubt a number of them are1 they lie above man's control4 ,but when there are indications that causes secondary to these are producing some dire effect1 and when we know that these secondary causes may be modified1 it is sufficient evidence to prove that man is permitted to control thus far the afflictions which are sent to try his powers4 ,we find a disease winging its way from lane to alley and closed court1 sweeping with destructive violence its way through damp cellars and crowded attics2 it is rife with mischief along the banks of reeking ditches1 and on the borders of filthy streams4 ,certain it is1 therefore1 that some ultimate connexion exists between the conditions of dirt and this speedy death4 ,can science tell of these8 has it yet searched out the connecting link8 ,let the question be answered by a few facts4 ,when the cholera first made its appearance1 and subsequently1 it has been observed that the electrical intensity of the atmosphere was unusually low4 ,the disease has departed1 and it is then found that the electricity of the air has been restored to its ordinary condition4 ,this appears to show some connexion2 but how do these conditions link this physical force with the ditch-seeking disease8 ,from all stagnant places1 from all the sinks of overcrowded humanity1 from fermenting vegetable and from putrefying animal matter1 there are constantly arising poisonous exhalations to do their work of destruction4 ,where death and decay is a law1 this must of necessity constantly occur2 but the poisonous reek may be diffused1 or it may be concentrated1 and ,nature has provided for this1 and ordered the means for rendering the poison harmless4 ,by the agency of electricity1--probably1 too1 by the influence of light1--the oxygen in the air undergoes a peculiar change1 by which it is rendered far more energetic than it is in its ordinary state4 ,this is the condition to which the name of ozone has been applied4 ,now1 this ozone1 or this peculiar oxygen1 always exists in the air we breathe2 but its quantity is subject to great and rapid variations4 ,it is found that when electrical intensity is high the quantity of this principle is great2 when the electrical intensity is low1 as in the cholera years1 the proportion of ozone is relatively low4 ,this remarkable chemical agent possesses the power of instantly combining with organic matter1--of removing with singular rapidity all noxious odours2 and it would appear to be the most active of all known disinfectants4 ,may we not infer from the facts stated that the pestilence we dread is the result of organic poison1 which from a deficiency of ozone1--its natural antidote1--exerts its baneful influences on humanity4 ,this deficiency is due to alterations in the electrical character of the air1 possibly dependent upon phenomena taking place in the sun itself1 or it may be still more directly influenced by variations in the character of solar light1 which we have not yet detected1 by which the conditions of the electric power are determined4 ,this may be a line along which it is fair to push enquiry4 ,but such an enquiry must be made in all the purity of the highest inductive philosophy1 and speculation must be held firmly in the controlling chains of experiment and observation4 ,in the truths1 however1 which are known to us1 there is so much harmony and consistence that even the melancholy theme links itself--a tragedy--with the ,poetry of ,science4 ,it has been thought1 and much satisfactory evidence has been brought forward to support the idea1 that the earth's magnetism is due to currents of electricity circulating around the globe2 as a great natural current from east to west--that1 indeed1 it has an unvarying reference to the motion of the earth in relation to the sun4#aeb ,these terrestrial currents1 as they have without doubt a very important bearing on the structural conditions of the rock-formations and the distribution of minerals1 require an attentive consideration2 but we must1 in the first place1 examine1 as far as we know1 the influences exerted1 or supposed to be exerted1 by electricity1 in its varied forms4 ,the phenomena of vitality have1 by many1 been considered as immediately dependent upon its influence2 and a rather extensive series of experiments has been made in support of this hypothesis4 ,the researches of ,philip on the action of the organs of digestion1 when separated from their connection with the brain1 but united with a galvanic battery1 have been proved by ,dr4 ,reid to be delusive2#aec since1 as the organ is not removed from the influence of the living principle1 it is quite evident that the electricity here is only secondary to some more important power4 ,matteucci has endeavoured to show that nervous action is intimately connected with electric excitation1 and that electricity may be made a measurer of nervous irritability4#aed ,there can be no doubt that a peculiar susceptibility to excitement exists in some systems1 and this is very strikingly shown in the disturbances produced by electric action2 but in the experiments which have been brought forward we have only the evidence that a certain number of muscular contractions are exhibited in one animal by a current of electricity1 giving a measured effect by the voltameter1 which are different from those produced upon another by a current of the same power4 ,an attempt has recently been made by ,mr4 ,a4 ,smee to reduce the electrical phenomena connected with vitality to a more exact system than had hitherto been done4 ,we cannot1 however1 regard the attempt as successful4 ,the author has trusted almost entirely to analogical reasoning1 which is in science always dangerous4#aee ,in the development of electricity during the operation of the vital force1 we see only the phenomena produced by the action of any two dissimilar chemical compounds upon each other4 ,it has been thought that the structure of the brain presents an analogy to that of the galvanic battery1 and the nerves represent the conducting wires4 ,although1 however1 some of the conditions appear similar1 there are many which have no representatives in either the mechanical structure or the physical properties of the brain1 so far as we know it4 ,that the brain is the centre1 the source1 and termination of sensation is very clearly proved by physiological investigations4 ,that the nerves are the media by which all sensation is conveyed to the brain1 and also the instruments by which the will exerts its power over the muscles1 is equally well established4 ,but to say that we have any evidence to support the idea that electricity has aught to do directly with these great physiological phenomena1 would be a bold assertion1 betraying a want of due caution on the part of the investigator4 ,that electric effects are developed during the operations of vitality is most certain4 ,such must be the case1 from the chemical changes taking place during respiration and digestion1 and the mechanical movements by which1 even during external repose1 the necessary functions of the body are carried on4 ,whether electricity is the cause of these1 or an effect arising from them1 we need not stop to examine1 as this is1 in the present state of our knowledge1 a mere speculation4 ,we have no evidence that electricity is an exciting power1 but rather that it is one of those forces which tend to establish the equilibrium of matter4 ,when disturbed--when its equilibrium is overset--it does1 in its efforts to regain its stability1 produce most remarkable effects4 ,an electrical machine must be rubbed to exhibit any force4 ,in all galvanic arrangements1 even the most simple1 dissimilar bodies are brought together1 and the latent electricity of both is disturbed2 and1 even in the magnet1 it is only when this takes place that its electrical powers are developed4 ,in the ,gymnotus1 electricity appears to be dependent upon the power of the will of the animal2 but even in this extraordinary fish1 it is only under peculiar conditions that the electrical excitement takes place1 and 8what they inflict1 they feel0 during the restoration of that equilibrium which is necessary to their healthy state4 ,in every case1 therefore1 we see that some power far superior to this is the ultimate cause2 indeed1 light and heat1 and probably actinism1 appear to stand superior to this principle2 and on these1 in some combined mode of action1 in all probability1 sensible electricity is dependent4 ,beyond even these elements1 largely as they are engaged in the organic and inorganic changes of this world1 there are occult powers which may never be understood by finite beings4 ,we advance step by step from the most solid to the most ethereal of material creations1 and we examine a series of extraordinary effects produced by powers which we know not whether to regard as material or immaterial1 so subtile are they4 ,on these1 it appears1 we may exhaust our inductive investigations--we may discover the laws by which these principles act upon the grosser elements1 and develope phenomena of a very remarkable kind which have been unobserved or misunderstood4 ,whether light1 heat1 and electricity are modifications of one power1 or different powers very closely united in action1 is a problem we may possibly solve2 but to know what they are1 appears to be beyond the hopes of science2 and it were idle to dream of elucidating the causes hidden beyond these forces1 and by which they are regulated in all their actions on dead or living matter4 ,m4 ,du ,bois ,raymond1 from a series of researches remarkable alike for their difficulty and the delicacy with which they have been pursued1 draws the following1 amongst many others1 as his conclusions as to the connection of electricity and vital phenomena4 ,the muscles and nerves1 including the brain and the spinal chord1 are endowed during life with an electromotive power1 which acts according to a definite law4 ,the electromotive power lasts after death1 or in dissected nerves and muscles after separation from the body of the animal1 as long as the excitability of the nervous and muscular fibre2 whether these fibres are permitted to die gradually from the cessation of the conditions necessary to the support of life1 or whether they are suddenly deprived of their vital properties by heat or chemical action4 ,let us not suppose for a moment that these conclusions indicate in the remotest degree that electricity is life1--that vital power is due to electricity4 ,during life1 with every motion1 and1 indeed1 with every emotion1 whether we move a muscle or exert the mind1 there is a change of state4 ,the result of this is chemical phenomena1--heat and electricity2 but these are not life4 ,we excite them equally by giving motion to a dead mass4 ,notwithstanding the assertions of those who have zealously followed the path of ,mesmer1 and examined1 or they have thought so1 the psychological effects dependent upon some strange physiological conditions1 there is not an experiment on record1--there is not an observation worthy of credit1 which shows that electricity has any connection with their results4 ,all around their subject is uncertainty3 doubt involves every experiment1 and deception clouds a large number4 ,some few grains of truth1 and these are sufficiently strange1 are mixed up in an enormous mass of error4 ,all the phenomena of life1--of the vis vit or vitality1 are beyond human search4 ,all the physical forces1 or elements1 we may examine by the test of experiment3 but the principle on which sensation depends1 the principle even upon which vegetable life depends1 cannot be tested4 ,life is infinitely superior to every physical force2 it holds them all in control1 but is not itself controlled by them2 it keeps its state sacred from human search1--the invisible hidden behind the veil of mortality4 ,during changes in the electrical conditions of the earth and atmosphere1 vegetables give indications of being in a peculiar manner influenced by this power4 ,it is proved by experiments that the leaves of plants are among the best conductors of electricity1 and it has hence been inferred that it must necessarily be advantageous to vegetation4 ,that vegetable growth is1 equally with animal growth1 subject to electricity1 as one of its quickening powers1 must be admitted2 but all experiments which have been fairly tried with the view of stimulating the growth of plants by its agency1 have given results of a negative character4#aef ,that a galvanic arrangement may produce chemical changes in the soil1 which may be advantageous to the plant1 is probable2 but that a plant can be brought to maturity sooner1 or be made to develope itself more completely1 under the direct action of electrical excitation1 appears to be one of those dreams of science which will have a place amongst the marvels of alchemy and the fictions of astrology4 ,an attentive examination of all the conditions necessary for the satisfactory development of the plant1 will render it evident1 that although the ordinary electrical state of the earth and atmosphere must influence the processes of germination and vegetable growth1 yet that any additional excitement must be destructive to them4 ,the wonders wrought by electrical power are marvellous2 a magic influence is exerted by it1 and naturally the inquiring mind is led at first to believe that electricity is the all-powerful principle of creation2 but a little reflection will serve to convince us that it is a subordinate agent1 although a powerful one4 ,in proceeding with our examination of the phenomena which present themselves in connection with the terrestrial currents1 we purposely separate magnetism from those more distinct electro-chemical agencies which play so important a part in the great cosmical operations4 ,electricity1 we have already stated1 flows through or involves all bodies2 but1 like heat1 it appears to undergo a very remarkable change in becoming associated with some forms of matter4 ,we have the phenomena of magnetism when an electric current circulates through a metallic wire1 and it would appear that all other bodies acquire a peculiar polar condition under the influence of this principle1 which will be explained in the next chapter4 ,the rocks1 taken as masses1 will not conduct an electric current when dry3 granite1 porphyry1 slate1 and limestone1 obstructing its passage even through the smallest spaces4 ,but all the metallic formations admit of its circulating with great freedom4 ,this fact it must1 however1 be remembered does not in any way interfere with the hypothesis of the existence of electricity in all bodies1 in what we must regard as its latent state1 from which1 under prescribed conditions1 it may be readily liberated4 ,neither does it affect the question of circulation1 in relation to the great diffusion of electricity which we suppose to exist through all nature1 and to move in obedience to some fixed law4 ,we know that through the superficial strata electric currents circulate freely1 whether they are composed of clay1 sand1 or any mixture of these with decomposed organic matter2 indeed1 that with any substance in a moist state they suffer no interruption4 ,the electricity of mineral veins has attracted much attention1 and numerous investigations into the phenomena which these metalliferous formations present1 have been made from time to time4#aeg ,by inserting into the mass of a copper lode1 or vein1 in situ1 a metallic wire1 which shall be connected with a measurer of galvanic action1 a wire also from the instrument being brought into contact with another lode1 an immediate effect is generally produced1 showing that a current is traversing through the wires from one lode to the other1 and completing the circulation probably over the dark face of the rock in which the fissures forming the mineral veins exist4#aeh ,the currents thus detected are often sufficiently active to deflect a magnetic needle powerfully1 to produce1 slowly1 electro-chemical decomposition1 and to render a bar of iron magnetic4 ,these currents must not be confounded with the great electrical movements around the earth4 ,they are only to be detected in those mineral formations in which there is evidence of chemical action going on1 and1 the greater the amount of this chemical operation1 the more energetic are the electrical currents4#aei ,we have1 however1 very good evidence that these local currents have1 of themselves1 many peculiar influences4 ,it not unfrequently happens that owing to some great disturbance of the crust of the earth1 a mineral vein is dislocated1 and one part either sinks below1 or is lifted above its original position2 the fissures formed between the two being usually filled in with clay or with crystalline masses of more recent formation than the fissure itself4 ,it is frequently found that these 8cross courses10 as they are called in mining language1 contain ores of a different character from those which constitute the mineral vein2 for instance1 in them nickel1 cobalt1 and silver are not unfrequently discovered4 ,when these metals are so found1 they almost invariably occur between the ends of the dislocated lode1 and often take a curvilinear direction1 as if they were deposited along a line of electrical force4#afj ,in the laboratory such an arrangement has been imitated1 and in a mass of clay fixed between the galvanic plates1 after a short period a distinct formation of a mineral vein has taken place4#afa ,by the action1 too1 of weak electrical currents1 ,becquerel1 ,crosse1 and others1 have been successful in imitating nature so far as to produce crystals of quartz and other minerals4 ,in addition to this evidence1 in support of the electrical theory of the origin of mineral veins1 it can be experimentally shown that a schistose structure may be given to clays and sandstone by voltaic action4#afb ,there is often a very remarkable regularity in the direction of mineral veins3 throughout ,cornwall1 for instance1 they most commonly have a bearing from the ,e4 of ,n4 to the ,w4 of ,s4 ,it has hence been inferred that they observe some relation to the magnetic poles of the earth4 ,however this may be1 it is certain that the ore in any lodes which are in a direction at right angles1 or nearly so1 to this main line1 differs in character from that found in these1 so called1 east and west lobes4#afc ,the sources of chemical action in the earth are numerous4 ,water percolating through the soil1 and finding its way to great depths through fissures in the rocks1 carries with it oxygen and various salts in solution4 ,water again rising from below1 whether infiltrated from the ocean or derived from other sources1 is usually of a high temperature1 and it always contains a large quantity of saline matter4#afd ,by these causes alone chemical action must be set up4 ,chemical change cannot take place without a development of electricity3 and it has been proved that the quantity of electricity required for the production of any change is equal to that contained in the substances undergoing such change4 ,thus a constant activity is maintained within the caverns of the rock by the agency of the chemical and electrical elements1 and mutations on a scale of great grandeur are constantly taking place under some directive force4 ,the mysterious gnome1 labouring--ever labouring--in the formation of metals1 and the mischievous ,cobalus of the mine1 are the poor creations of superstition4 ,a vague fear is spread amongst great masses of mankind relative to the condition of the dark recesses of the earth2 a certain unacknowledged awe is experienced by many on entering a cavern1 or descending a mine3 not the natural fear arising from the peculiarity of the situation1 but the result of a superstitious dread1 the effect of a depraved education1 by which they have been taught to refer everything a little beyond their immediate comprehension to supernatural causes4 ,the spirit of demon worship1 as well as that of hero worship1 has passed from the early ages down to the present2 and under its influence the genii of the ,east and the demons of the ,west have preserved their traditionary powers4 ,fiction has employed itself with the utmost license in giving glowing pictures of treasures hidden in the earth's recesses4 ,the caverns of ,chilminar1 the cave of ,aladdin1 the abodes of the spirits of the ,hartz1 and the dwellings of the fairies of ,england1 are gem-bespangled and gold-glistening vaults1 to which man has never reached4 ,the pictures are pleasing2 but although they have the elements of poetry in them1 and delight the young mind1 they want the sterling character of scientific truth2 and the wonderful researches of the plodding mineralogist have developed more beauty in the caverns of the dark rock than ever fancy painted in her happiest moments4 ,in all probability the action of the sun's rays upon the earth's surface1 producing a constantly varying difference of temperature1 and also the temperature which has been observed as existing at great depths1 give rise to thermo-electrical currents1 which may play an important part in the results thus briefly described4 ,in connection with these great natural operations1 explaining them1 and being also1 to some extent1 explained by them1 we have the very beautiful application of electricity to the deposition of metals1 called the ,electrotype4 ,applying the views we have adopted to this beautiful discovery1#afe the whole process by which these metallic deposits are produced will be yet more clearly understood4 ,by the agency of the electric fluid1 liberated in the galvanic battery1 a disturbance of the electricity of the solution of copper1 silver1 or gold1 is produced1 and the metal is deposited2 but1 instead of allowing the acid in combination to escape1 it has presented to it some of the same metal as that revived1 and1 consequently1 it combines with it1 and this compound1 being dissolved1 maintains the strength of the solution4#aff ,a system of revival1 or decomposition1 is carried on at one pole1 and one of abrasion1 or more correctly speaking1 of composition and solution1 at the other4 ,by taking advantage of this very extraordinary power of electricity1 we now form vessels for ornament or use1 we gild or silver all kinds of utensils1 and give the imperishability of metal to the most delicate productions of nature--her fruits1 her flowers1 and her insects2--and over the finest labours of the loom we may throw coatings of gold or silver to add to their elegance and durability4 ,nor need we employ the somewhat complex arrangement of the battery3 we may take the steel magnet1 and1 by mechanically disturbing the electricity it contains1 we can produce a current through copper wires1 which may be used1 and is extensively employed1 for gilding and silvering4#afg ,the earth itself may be made the battery1 and1 by connecting wires with its mineral deposits1 currents of electricity have been secured1 and used for the production of electrotype deposit4#afh ,the electrotype is but one of the applications of electricity to the uses of man4 ,this agent has been employed as the carrier of thought2 and with infinite rapidity1 messages of importance1 communications involving life1 and intelligences outstripping the speed of coward crime1 have been communicated4 ,there will be no difficulty in understanding the principle of this1 although many of the nice mechanical arrangements1 to ensure precision1 are of a somewhat elaborate character4 ,the entire action depends on the deflection of a compass-needle by the passage of an electric current along its length4 ,if at a given point we place a galvanic battery1 and at twenty or one hundred miles distance from it a compass-needle1 between a wire brought from1 and another returning to the battery1 the needle will remain true to its polar direction so long as the wires are unexcited2 but the moment connection is made1 and the circuit is complete1 the electricity of the whole extent of wire is disturbed1 and the needle is thrown at right angles to the direction of the current4 ,provided a connection between two points can be secured1 however remote they are from each other1 we thus1 almost instantaneously1 convey any intelligence4 ,the effects of an electric current would appear at a distance of #egf1jjj miles in a second of time2 and to that distance1 and with that speed1 it is possible1 by ,professor ,wheatstone's beautiful arrangements1 to convey whispers of love or messages of destruction4 ,the enchanted horse of the ,arabian magician1 the magic carpet of the ,german sorcerer1 were poor contrivances1 compared with the copper wires of the electrician1 by which all the difficulties of time and the barriers of space appear to be overcome4 ,in the ,scandinavian mythology we find certain spiritual powers of evil enabled to pass with imperceptible speed from one remote point to another1 sowing the seeds of a common ruin amongst mankind4 ,such is the morbid creation of a wild yet highly endowed imagination4 ,the spirit of evil diffuses itself in a remarkable manner1 and1 indeed1 we might almost assign to it the power of ubiquity2 but in reality its advance is progressive1 and time enters as an element into any calculation on its diffusion4 ,electricity is instantaneous in action2 as a spirit of peace and good-will it can overtake the spirit of evil1 and divert it from its designs4 ,may we not hope that the electrical telegraph1 making1 as it must do1 the whole of the civilized world enter into a communion of thought1 and1 through thought1 of feeling with each other1 will bind us up in one common brotherhood1 and that1 instead of misunderstanding and of misinterpreting the desires and the designs of each other1 we shall learn to know that such things as 8natural enemies0 do not exist8 ,to hope to break down the great barrier of language is perhaps too much2 but assuredly we may hope that1 as we must do when closer and more intimate relations are secured by the aids of science1 the barrier of prejudice may be razed to the ground1 and not one stone left to stand upon another8 ,our contentions1 our sanguinary wars1 consecrated to history by the baptism of blood1 have in every1 or in nearly every1 instance sprung from the force of prejudice1 or the mistakes of politicians1 whose minds were narrowed to the limits of a convention formed for perpetuating the reign of ignorance4 ,and can anything be more in accordance with the spirit of all that we revere as holy1 than the idea that the elements employed by the ,all ,infinite in the works of physical creation shall be made1 even in the hands of man1 the ministering angels to the great moral redemption of the world8 ,associate the distant nations of the earth1 and they will find some common ground on which they may unite4 ,mortality compels a dependence2 and there are charities which spring up alike in the breast of the savage and the civilized man1 which will not be controlled by the cold usages of pride1 but which1 like all truths1 though in a still small voice1 speak more forcibly to the heart than errors can1 and serve as links in the great chain which must bind mankind in a common brotherhood4 8,none are all evil10 and the best have much to learn of the amenities of life from him who yet lives in a 8state of nature10 or rather from him whose sensualities have prevailed over his intellectual powers1 but who still preserves many of the noblest instincts1 to give them no higher term1 which other races1 proud of their intelligence1 have thrown aside4 ,time and space have hitherto prevented the accomplishment of this2 electricity and mechanics promise to subdue both2 and we have every reason to hope those powers are destined to accelerate the union of the vast human family4 ,electrical power has also been employed for the purpose of measuring time1 and by its means a great number of clocks can be kept in a state of uniform correctness1 which no other arrangement can effect4 ,a battery being united with the chief clock1 which is itself connected by wires with any number of clocks arranged at a distance from each other1 has the current continually and regularly interrupted by the beating of the pendulum1 which interruption is experienced by all the clocks included in the electric circuit2 and1 in accordance with this breaking and making contact1 the indicators or hands move over the dial with a constantly uniform rate4 ,instead of a battery the earth itself has supplied the stream of electric fluid1 with which the rate of its revolutions has been registered with the utmost fidelity4#afi ,electricity1 which is now employed to register the march of time1 rushes far in advance of the sage who walks with measured tread1 watching the falling sands in the hour-glass4 ,the earth is spanned and the ocean pierced by the wires of the electric telegraph4 ,already1 from the banks of the ,thames to the shores of the ,adriatic1 our electric messenger will do our bidding4 ,the telegraph is making its way through ,italy1 and it is dipping its wires in the ,mediterranean1 soon to reach the coast of ,africa4 ,they will then run along the ,african shores to ,egypt and ,turkey1 and still onward until they unite with the telegraphs of ,india1 of which three thousand miles are in progress4 ,from ,hindostan these wondrous wires will run from island to island in the ,indian ,archipelago1 and thus connect ,australia and ,new ,zealand with ,europe4 ,in a few years we may expect to have an instantaneous report in ,london of the extraordinary 8nugget0 discovered by some fortunate gold-digger2 and the exile from his native land in the ,islands of the ,south ,pacific ,ocean1 may learn every hour1 if he will1 of the doings of his family and friends in some village home of ,england4 ,,footnotes3 #acf ,trait de ,physique3 ,m4 ,biot1 vol4 vii4 ,becquerel3 ,annales de ,chimie1 vol4 xlvi4-xlix4 ,faraday's ,experimental ,researches in ,electricity1 #b vols41 #ahcj-ahdd4 ,a ,speculation touching ,electric ,conduction and the ,nature of ,matter3 by ,michael ,faraday1 ,d4,c4,l41 ,f4,r4,s42 ,philosophical ,magazine1 vol4 xxiv41 #ahcf4 ,objections to the theories severally of ,franklin1 ,dufay1 and ,ampre1 with an attempt to explain ,electrical ,phenomena by statical or undulatory polarization3 by ,robert ,hare1 ,m4,d41 ,emeritus ,professor of ,chemistry in the ,university of ,pennsylvania4 #acg 8,a good piece of gutta percha will insulate as well as an equal piece of shell-lac1 whether it be in the form of sheet1 or rod1 or filament2 but being tough and flexible when cold1 as well as soft when hot1 it will serve better than shell-lac in many cases where the brittleness of the latter is an inconvenience4 ,thus it makes very good handles for carriers of electricity in experiments on induction2 not being liable to fracture in the form of thin band or string1 it makes an excellent insulating suspender2 a piece of it in sheet makes a most convenient insulating basis for anything placed on it4 ,it forms excellent insulating plugs for the stems of gold-leaf electrometers1 when they pass through sheltering tubes1 and larger plugs form good insulating feet for electrical arrangements2 cylinders of it1 half an inch or more in diameter1 have great stiffness1 and form excellent insulating pillars4 ,in these and in other ways its power as an insulator may be useful40--,on the use of ,gutta ,percha in ,electrical ,insulation3 by ,dr4 ,faraday2 ,philosoph4 ,mag41 ,march1 #ahdh4 ,the following deductions have been given by ,faraday1 in his ,researches in ,electricity1 a work of most extraordinary merit1 being one of the most perfect examples of fine inductive philosophy which we possess in the ,english language3-- 8,all bodies conduct electricity in the same manner from metals to lacs and gases1 but in very different degrees4 8,conducting power is in some bodies powerfully increased by heat1 and in others diminished1 yet without one perceiving any accompanying essential electrical difference1 either in the bodies1 or in the change occasioned by the electricity conducted4 8,a numerous class of bodies insulating electricity of low intensity1 when solid1 conduct it very freely when fluid1 and are then decomposed by it4 8,but there are many fluid bodies which do not sensibly conduct electricity of this low intensity2 there are some which conduct it and are not decomposed2 nor is fluidity essential to decomposition4 8,there are but two bodies 7sulphuret of silver and fluoride of lead7 which1 insulating a voltaic current when solid1 and conducting it when fluid1 are not decomposed in the latter case4 8,there is no strict electrical distinction of conduction which can as yet be drawn between bodies supposed to be elementary1 and those known to be compounds40 #ach ,faraday's ,speculation on the ,nature of ,matter1 already referred to4 #aci ,experimental ,researches3 by ,dr4 ,faraday4 ,chemical ,decomposition1 p4 #aea4 #adj ,karsten2 ,poggendorff's ,annalen1 vol4 lvii4 #ada ,trait ,exprimental de l'lectricit et du ,magntisme3 ,becquerel1 #ahcd1 ,priestley's ,introduction to ,electricity4 ,on ,electricity in ,equilibrium3 ,dr4 ,young's ,lectures4 #adb ,faraday's ,experimental ,researches on ,electricity4 ,this philosopher has shown1 by the most conclusive experiments1 8that the electricity which decomposes1 and that which is evolved by the decomposition of1 a certain quantity of matter1 are alike4 ,what an enormous quantity of electricity1 therefore1 is required for the decomposition of a single grain of water6 ,we have already seen that it must be in quantity sufficient to sustain a platinum wire #a_/ajd of an inch in thickness1 red hot1 in contact with the air1 for three minutes and three quarters4 ,it would appear that #hjj1jjj charges of a ,leyden battery1 charged by thirty turns of a very large and powerful plate machine1 in full action--a quantity sufficient1 if passed at once through the head of a rat or cat1 to have killed it as by a flash of lightning--are necessary to supply electricity sufficient to decompose a single grain of water2 or1 if ,i am right1 to equal the quantity of electricity which is naturally associated with the elements of that grain of water1 endowing them with their mutual chemical affinity40 #adc ,experimental ,researches3 ,faraday4 #add ,the appearance of acid and alkaline matter1 in water acted on by a current of electricity1 at the opposite electrified metallic surfaces1 was observed in the first chemical experiments made with the column of ,volta--7see ,nicholson's ,journal1 vol4 iv4 p4 #ahc1 and vol4 iv4 p4 #bfa1 for ,mr4 ,cruickshank's ,experiments2 and ,annales de ,chimie1 tom4 xxxvii4 p4 #bcc1 for those of ,m4 ,desormes73 ,on some ,chemical ,agencies in ,electricity3 by ,sir ,humphry ,davy4--,philosophical ,transactions for #ahjg4 ,the various theories of electro-chemical decomposition are carefully stated by ,faraday1 in his fifth series of ,experimental ,researches on ,electricity1 in which he thus states his own views3--8,it appears to me that the effect is produced by an internal corpuscular action exerted according to the direction of the electric current1 and that it is due to a force either superadded to or giving direction to the ordinary chemical affinity of the bodies present4 ,the body under decomposition may be considered as a mass of acting particles1 all those which are included in the course of the electric current contributing to the final effect2 and it is because the ordinary chemical affinity is relieved1 weakened1 or partly neutralized by the influence of the electric current in one direction parallel to the course of the latter1 and strengthened or added to in the opposite direction1 that the combining particles have a tendency to pass in opposite courses40 #ade 8,this capital discovery 7chemical decomposition of electricity7 appears to have been made in the first instance by ,messrs4 ,nicholson and ,carlisle1 who observed the decomposition of water so produced4 ,it was speedily followed up by the still more important one of ,berzelius and ,hisinger1 who ascertained it as a general law1 that1 in all the decompositions so effected1 the acids and oxygen become transferred and accumulated around the positive1 and hydrogen1 metals1 and alkalies around the negative1 pole of a voltaic circuit2 being transferred in an invisible1 and1 as it were1 a latent or torpid state1 by the action of the electric current1 through considerable spaces1 and even through large quantities of water or other liquids1 again to reappear with all their properties at their appropriate resting-places40--,discourse on the ,study of ,natural ,philosophy3 by ,sir ,john ,herschel1 ,bart41 ,f4,r4,s4 #adf ,numerous beautiful illustrations of this fact will be found in ,becquerel's ,trait ,exprimental de l'lectricit et du ,magntisme4 #adg ,see ,le ,feu lmentaire of l',abb ,nollet2 ,leons de ,physique1 tom4 vi4 p4 #beb2 ,du ,pouvoir thermo-lectrique1 by ,m4 ,becquerel--,annales de ,chimie1 vol4 xli4 p4 #cec2 also a ,memoir by ,nobili1 ,bibliothque ,universelle1 vol4 xxxvii4 p4 #ae2 ,experimental ,contributions towards the theory of ,thermo-,electricity by ,mr4 ,j4 ,prideaux--,philosophical ,magazine1 vol4 iii41 ,third ,series2 ,on the ,thermo-,magnetism of ,homogeneous ,bodies1 with illustrative experiments1 by ,mr4 ,william ,sturgeon--,philosophical ,magazine1 vol4 x4 p4 #a-aaf1 ,new ,series4 ,botto made magnets and obtained chemical decomposition4 ,antinori produced the spark4 ,mr4 ,watkins heated a wire in ,harris's ,thermo-,electrometer4 #adh ,a very ingenious application of the knowledge of this fact was suggested by ,mr4 ,solly1 by which the heat of a furnace could be constantly registered at a very considerable distance from it4 ,see ,description of an ,electric ,thermometer3 by ,e4 ,solly1 ,jun41 ,esq4 ,philosophical ,magazine1 vol4 xx4 p4 #cia4 ,new ,series4 #adi ,humboldt2 ,personal ,narrative1 ,chap4 xvii4--,annales de ,chimie1 vol4 xiv4 p4 #ae4 #aej ,experimental ,researches on ,electricity4 ,series xv4 ,consult ,sir ,humphry ,davy3 ,an ,account of some ,experiments on the ,torpedo4--,philosophical ,transactions1 #ahbi1 p4 #ae4 ,john ,davy1 ,m4,d41 ,f4,r4,s43 ,an ,account of some ,experiments and ,observations on the ,torpedo1 ibid41 #ahcb1 p4 #bei2 and the same author's ,observations on the ,torpedo1 with an ,account of some ,additional ,experiments on its ,electricity2 and ,matteucci1 ,bibliothque ,universelle1 #ahcg1 vol4 xii4 p4 #agd4 #aea ,on ,lightning ,conductors1 by ,sir ,william ,snow ,harris2 ,observations on the ,action of ,lightning ,conductors1 by ,w4 ,snow ,harris1 ,esq41 ,f4,r4,s4--,london ,electrical ,society's ,transactions4 ,numerous valuable papers ,on ,electricity1 by ,sir ,william ,harris1 will be found in the ,philosophical ,transactions4 #aeb ,adopting1 to a certain extent1 this view1 ,faraday1 in his ,electrical ,nomenclature1 proposed for the word pole to substitute anode 71 upwards1 and 1 a way71 the way which the sun rises2 and cathode 71 downwards1 and 1 a way71 the way which the sun sets4 ,the hypothesis belongs essentially to ,ampre4 ,objections to the ,theories severally of ,franklin1 ,dufay1 and ,ampre1 with an ,effort to ,explain ,electrical ,phenomena by ,statical or ,undulatory ,polarisation1 by ,robert ,hare1 ,m4,d41 ,pennsylvania1 will well repay an attentive perusal4 #aec ,inquiry into the ,laws of the ,vital ,functions4--,philosophical ,transactions1 #ahae1 #ahbb2 ,some ,observations relating to the ,functions of ,digestion1 ibid41 #ahbi3 ,on the ,powers on which the ,functions of ,life in the more perfect animals depend1 and on the manner in which they are associated in the production of their more complicated results1 by ,a4 ,p4 ,w4 ,philip1 ,m4,d41 ,f4,r4,s41 ,l4 and ,e4--,the following extract from the last-quoted of ,dr4 ,philip's ,memoirs1 will give a general view of the conclusions of that eminent physiologist3--8,with respect to the nature of the powers of the living animal which we have been considering1 the sensorial and muscular powers1 and the powers peculiar to living blood1 we have found belong to the living animal alone1 all their peculiar properties being the properties of life4 ,the functions of life may be divided into two classes1 those which are affected by the properties of this principle alone1 and those1 by far the most numerous class1 which result from the co-operation of these properties with those of the principles which operate in inanimate nature4 ,the nervous power we have found to be a modification of one of the latter principles1 because it can exist in other textures than those to which it belongs in the living animal1 and we can substitute for it one of those principles without disturbing the functions of life4 8,late discoveries have been gradually evincing how far more extensive than was supposed1 even a few years ago1 is the dominion of electricity4 ,magnetism1 chemical affinity1 and 7,i believe from the facts stated in the foregoing paper1 it will be impossible to avoid the conclusion7 the nervous influence1 the leading power in the vital functions of the animal frame1 properly so called1 appear all of them to be modifications of this apparently universal agent2 for ,i may add we have already some glimpses of its still more extensive dominion40 ,refer to ,dr4 ,reid's papers4 #aed ,electro-physiological ,researches3 by ,signor ,carlo ,matteucci2 ,phil4 ,trans4 #ahde1 p4 #bic1 and subsequent years4 #aee ,electro-,biology3 by ,alfred ,smee1 ,esq4 #aef ,observations of ,electric ,currents in ,vegetable ,structures3 by ,golding ,bird1 ,esq41 ,f4,l4,s42 ,magazine of ,natural ,history1 vol4 x4 p4 #bdj4 ,in this paper ,dr4 ,bird remarks that his experiments lead to the conclusion that vegetables cannot become so charged with electricity as to afford a spark2 that electrical currents of feeble tension are always circulating in vegetable tissues2 and that electrical currents are developed during germination from chemical action4 #aeg ,on ,mineral ,veins3 by ,robert ,were ,fox1 ,esq42 ,fourth ,report of the ,royal ,cornwall ,polytechnic ,society4 ,on the ,electro-magnetic ,properties of ,metalliferous ,veins in the mines of ,cornwall3 by ,robert ,w4 ,fox1 ,esq42 ,phil4 ,trans4 #ahcj1 p4 #cii4 #aeh ,experiments and ,observations on the ,electricity of ,mineral ,veins3 by ,robert ,hunt and ,john ,phillips2 ,reports of the ,royal ,cornwall ,polytechnic ,society for #ahda-db4 ,on the ,electricity of ,mineral ,veins3 by ,mr4 ,john ,arthur ,phillips2 ,ibid41 #ahdc4 #aei ,in the lead lodes of ,lagylas and ,frongoch1 electrical currents were detected by ,mr4 ,fox1 but none in those of ,south ,mold and ,milwr1 in ,flintshire3 ,cornwall ,geological ,transactions1 vol4 iv4 ,in the lead veins of ,coldberry and ,skeers1 in ,teasdale1 ,durham1 the currents detected were very feeble3 ,reports of the ,bristol ,association1 #ahch4 ,von ,strombeck could detect no electric currents in the veins worked in the clay slate near ,saint ,goar1 on the ,rhine3 ,archiv4 fr ,mineralogie1 ,geognosie1 c41 von ,dr4 ,c4 ,j4 ,b ,karsten1 #ahcc4 ,professor ,reich1 however1 obtained very decided results at ,frisch ,glck1 ,neue ,hoffnung1 ,gottlob1 and in other mineral veins in the mining districts of ,saxony3 ,edinburgh ,new ,philosophical ,journal1 vol4 xxviii4 #ahci4 ,the irregularities are all to be explained by the presence or absence of chemical excitation4 #afj ,this was remarkably the case at ,huel ,sparnon1 near ,redruth1 where the cobalt was discovered between two portions of a dislocated lode2 and the same was observed by ,mr4 ,percival ,johnson in a small mine worked for nickel1 near ,st4 ,austell4 #afa ,on the process used for obtaining artificial veins in clay3 by ,t4 ,b4 ,jordan2 ,sixth ,annual ,report of the ,royal ,cornwall ,polytechnic ,society4 ,see also my memoir1 already referred to1 in the ,memoirs of the ,geological ,survey and ,museum of ,practical ,geology1 vol4 i4 #afb ,see ,becquerel1 ,trait ,experimental de l',electricit1 c4 ,electrical ,experiments on the formation of ,artificial ,crystals3 by ,andrew ,crosse1 ,esq42 ,british ,association ,reports1 vol4 v41 #ahcf4 ,the lamination of clay and other substances is described in my memoir referred to1 ,note p4 #bbf4 #afc ,report on the ,geology of ,cornwall1 ,devon1 and ,west ,somerset1 by ,sir ,henry ,t4 ,de la ,beche3 ,theoretical observations on the formation and filling of ,mineral ,veins and ,common ,faults1 p4 #cdi4 #afd ,the following analyses of waters from deep mines were made by me in #ahdj1 and1 with many others1 published in the ,reports of the ,royal ,cornwall ,polytechnic ,society4 ,consolidated ,mines1 ,gwennap1 ,cornwall4 ,in #a1jjj grains of water4 ,muriate of soda #ae ,sulphate of lime #e ,sulphate of iron #ae ,sulphate of copper #abe ,silica #ae ,alumina #c ---- ,total #cg ,united ,mines1 ,gwennap4 ,muriate of soda #aaj ,muriate of lime #ae ,sulphate of soda #ej ,sulphate of lime #ae ,sulphate of iron #ge ,alumina #e ,silica #ae ---- ,total #dfe ,great ,st4 ,george4 ,muriate of soda #ace ,sulphate of lime #gd ,carbonate of iron #gj ,alumina #ej ,carbonate of lime #aj ---- ,total #cd #afe ,the discovery of the electrotype has been disputed1 as all valuable discoveries are4 ,without1 however1 at all disparaging the merits of what had been done by ,mr4 ,jordan1 ,i am satisfied1 after the most careful search1 that the first person who really employed electro-chemical action for the precipitation of metals in an ornamental form1 was ,mr4 ,spencer1 of ,liverpool4 #aff ,see ,spencer1 ,instructions for the ,multiplication of works of ,art in ,metal by ,voltaic ,electricity4 ,novelties in ,experimental ,science3 ,griffin1 ,glasgow1 ,elements of ,electro-,metallurgy3 by ,alfred ,smee1 ,esq4 #afg ,the magneto-electrical machine is employed in ,birmingham for this purpose2 but ,i am informed by ,messrs4 ,elkington that they do not find it economical1 or rather that the electro-precipitation is carried on too slowly4 #afh ,this has been done by ,mr4 ,robert ,were ,fox1 at a mine near ,falmouth4 ,by connecting two copper wires with two lodes1 and bringing them1 at the surface1 into a cell containing a solution of sulphate of copper1 this gentleman obtained an electrotype copy of an engraved copper-plate4 #afi ,this has been most effectually accomplished by ,mr4 ,bain4 ,mr4 ,hobson has had an electric clock1 thus excited1 in action for several years4 ,,chapter ,x4 ,,magnetism4 ,magnetic ,iron--,knowledge of1 by the ,ancients--,artificial ,magnets--,electro-,magnets--,electro-,m agnetism--,magneto- ,electricity--,theories of ,magnetism--,the ,magnetic ,power of soft ,iron and ,steel--,influence of ,heat on ,magnetism--,terrestrial ,magnetism--,declination of the ,compass-needle--,variation of the ,earth's ,magnetism--,magnetic ,poles--,hansteen's ,speculations--,monthly and ,diurnal ,variation--,dip and ,intensity--,thermo-,magnetism--,aurora ,borealis--,magnetic ,storms--,magnetic conditions of ,matter--,diamagnetism1 c4 ,agreeably with the view now generally received1 that magnetism and electricity are but modifications of one force1 since they are found to stand to each other in the relation of cause and effect1 the separation which is here adopted1 of the consideration of their several phenomena1 may appear inappropriate4 ,the importance1 however1 of all that is connected with magnetism1 and the very decided difference which is presented by true magnetic action1 and that of frictional or chemical electricity1 is so great that it has been thought advantageous to adopt the present arrangement in reviewing the influence of terrestrial magnetism with which science has made us acquainted4 ,from a very early period a peculiar attractive force has been observed in some specimens of iron ore4 ,masses of this kind were found in ,magnesia1 and from that locality we derive the name given to iron in its polar condition4 ,this is confirmed by the following lines by ,lucretius3-- ,quod superest agere incipiam1 quo fdere fiat ,natura lapis hic ut ferrum ducere possit1 ,quem magnta vocant patrio de nomine ,graii ,magntum1 quia sit patriis in finibus ortus4 ,again we find ,pliny employing the term magnetic1 to express this singular power4 ,it was known to the ancients that the magnetic power of iron1 and the electric property of amber1 were not of the same character1 but they were both alike regarded as miraculous4 ,the ,chinese and ,arabians seem to have known ,magnetism at a period long before that at which ,europeans became acquainted with either the natural loadstone or the artificial magnet4 ,previously to ,a4,d4 #aba1 the magnet is distinctly mentioned in a ,chinese dictionary2 and in ,a4,d4 #dai it is stated in another of their books that ships were steered south by it4#agj ,the earliest popularly received account of its use in ,europe is1 that ,vasco de ,gama employed a compass in #adbg1 when that really adventurous navigator first explored the ,indian seas4 ,it is highly probable1 however1 that the knowledge of its important use was derived from some of the ,oriental nations at a much earlier period4 ,we have some curious descriptions of the leading stone or loadstone1 in the works of an ,icelandic historian1 who wrote in #ajfh4 ,the mariner's compass is described in a ,french poem of the date of #aaha2 and from ,torfus's ,history of ,norway1 it appears to have been known to the northern nations certainly in #abff4 ,we have not to deal with the history of magnetic discovery1 but so far as it tells of the strange properties which magnets are found to possess1 and the application of this knowledge to the elucidation of effects occurring in nature4 ,a brown stone1 in no respect presenting anything by which it shall be distinguished from other rude stones around it1 is found1 upon close examination1 to possess the power of drawing light particles of iron towards it4 ,if this stone is placed upon a table1 and iron filings are thrown lightly around it1 we discover that these filings arrange themselves in symmetric curves1 proceeding from some one point of the mass to some other2 and upon examining into this1 we shall find that the iron which has once clung to the one point will be rejected by the other4 ,if this stone is freely suspended1 we shall learn also that it always comes to rest in a certain position1--this position being determined by these points1 and some attractive force residing in the earth itself4 ,these points we call its poles2 and it is now established that this rude stone is but a small representative of our planet4 ,both are magnetic3 both are so in virtue of the circulation of currents of electricity1 or of lines of magnetic force1 as seen in the curves formed by the iron dust1 and the north pole of the one attracts the south pole of the other1 and the contrary4 ,by a confusion of terms we speak of the north pole of a compass-needle1 meaning that point which is always opposite to the north pole of the earth3 the truth being that the pole of the compass-needle1 which is so forcibly drawn to the north1 is a point in a contrary state1 or1 as we may express it1 really a south pole4 ,there is a power of a peculiar kind1 differing from gravitation1 or any other attracting or aggregating force with which we are acquainted1 which exists permanently in the magnetic iron stones1 and also in the earth4 ,what is this power8 ,magnetism may be produced in any bar of steel1 either by rubbing it with a loadstone1 or by placing it in a certain position in relation to the magnetic currents of the earth1 and1 by a blow or any other means1 disturbing its molecular arrangement4 ,this principle appears to involve the iron as with an atmosphere1 and to interpenetrate it4 ,by one magnet we may induce magnetism in any number of iron bars without its losing any of its original force4 ,as we have observed of the electrical forces already considered1 the magnet constantly presents two points in which there is a difference manifested by the circumstance that they are always drawn with considerable power towards the north or south poles of the earth4 ,that this power is of the same character as the electricity which we have been considering1 is now most satisfactorily proved4 ,by involving a bar of soft iron which1 being without any magnetic power1 is incapable of sustaining even an ounce weight1 with a coil of copper wire1 through which a galvanic current is passing1 the bar will receive1 by induction from the current1 an enormous accession of power1 and will1 so long as the current flows around it1 sustain many hundred pounds weight1 which1 the moment the current is checked1 fall away from it in obedience to the law of gravity4 ,thus the mere flow of this invisible agent around a mass of metal possessing no magneto-attractive power1 at once imparts this life-like influence to it1 and as long as the current is maintained1 the iron is endowed with this surprising energy4 ,this discovery1 which we owe to the genius of ,oersted1 and which has1 indeed1 given rise to a new science1 electro-magnetism1 may be regarded as one of the most important additions made to our knowledge4 ,current electricity is magnetic2 iron is not necessary to the production of magnetic phenomena1 although by its presence we secure a greater amount of power4 ,the copper wires which complete the circuit of a galvanic battery1 will attract and hold up large quantities of iron filings1 and the wires of the electric telegraph will do the same1 while any signal is being conveyed along them4 ,again1 all the phenomena common to galvanic electricity can be produced by merely disturbing the power permanently secured in the ordinary magnet4 ,it was thought that magnets would become weakened by this constant disturbance of their magnetism2 but1 since its application to the purpose of manufacture1 and magneto-electricity has been employed in electro-plating1 it has been found that continued action for many years1 during which enormous quantities of electricity have been thus given out and employed in producing chemical decomposition1 has not1 in the slightest degree1 altered their powers4 ,thus a small bar of metal is shown to be capable of pouring out1 for any number of years1 the principle upon which the phenomena of magnetism depend4 ,there are1 however1 differences1 and striking ones1 between ordinary and magnetic electricity4 ,in the magnet we have a power at rest1 and in the electrical machine or galvanic battery1 a power in motion4 ,ordinary electricity is stopped in its passage by a plate of glass1 of resin1 and many other substances2 but magnetism passes these with freedom1 and influences magnetic bodies placed on the other side4 ,it would appear1 though we cannot explain how1 that magnetism is due to some lateral influence of the electric currents4 ,a magnetic bar is placed over a copper wire1 and it hangs steadily in the direction of its length2 an electric current is passed along it1 and the magnet is at once driven to place itself across the wire4 ,upon this experiment1 in the main1 ,ampre founds his theory of terrestrial magnetism4 ,he supposes electrical currents to be traversing our globe from east to west1 and thus1 that the needle takes its direction1 not from the terrestrial action of any fixed magnetic poles1 but from the repulsion of these currents1 as is the case with the wire4 ,it has been found that wires1 freely suspended1 along which currents were passing in opposite directions1 revolve about each other1 or have an inclination to place themselves at right angles2 thus exhibiting the same phenomenon as the magnet and the conducting wire4 ,so far the hypothesis of ,ampre leads us most satisfactorily4 ,we see in the magnet one form of electricity1 and in the machine or battery another4 ,but why should not the electricity of the magnet1 electricity at rest1 exhibit the same powers as this force in motion8 ,oersted1 whose theory led him to the discovery of the fact of the magnetic power of an electric current1 of the establishment indeed of the new science--,,electro-,,magnetism1 regards the phenomena of a current passing a wire1 and its action on a needle1 as evidence of two fluids1 positive and negative1 traversing in opposite directions1 and mutually attracting and repelling4 ,he conceives that they pass the wires in a series of spirals2 that in the magnet1 by some peculiar property of the iron1 this conflict of the currents is reduced to an equilibrium1 and its power becomes manifested in its attractive force4#aga ,this does not1 however1 convey a clear idea to the mind4 ,it is curious that iron becomes magnetic in a superior degree to any other metal2 that steel retains permanently any magnetism imparted to it2 but that soft iron rapidly loses its magnetic power4 ,this must be in virtue of some peculiar arrangement of the molecules1 or some unknown physical condition of the atoms of the mass1 by which a continued influence is retained by the steel1 probably in a state of constant internal circulation4 ,it has1 however1 been shown that soft iron1 under certain circumstances1 may be made to retain a large amount of magnetic force4#agb ,if a horse-shoe shaped bar of soft iron is rendered magnetic by the circulation of an electric current around it1 while its two ends are united by an armature of soft iron1 so that it is capable of supporting many hundred pounds weight2 and we then1 by breaking the circuit1 stop the current1 taking care the armature is kept in contact1 the iron will not lose its magnetic property1 but will retain this power for many years4 ,if the connecting piece of iron1 the armature1 is removed1 the bar immediately loses all its magnetism1 and will not support even the armature itself4 ,this fact appears to confirm the idea that magnetism is due to the retention of electricity1 and that steel possesses the property of equalizing the opposing forces1 or of binding this principle to itself like an atmosphere4 ,the influence of heat on magnetism is so remarkable a proof of the dependence of this power upon molecular arrangement1 that it must not escape our notice4 ,to select but one of many experiments by ,mr4 ,barlow1 it was found that in a bar of malleable iron1 in which1 when cold1 the magnetic effect was #cj #j'1 all polarity ceased at a white heat1 that it was scarcely appreciable at a red heat1 but that at a blood-red heat it was equal to #da #j'4agc ,the more closely we examine the peculiarities of the magnetic power1 and particularly as they are presented to us in its terrestrial action1 the more surprising will its influence appear to be4 ,we have discovered a natural cause which certainly exercises a very remarkable power over matter1 and we have advanced so far in our investigations as to have learnt the secret of converting one form of force into another1 or of giving to a principle1 produced by one agency1 a new character under new conditions2 of changing1 in fact1 electricity into magnetism1 and from magnetism again evolving many of the effects of electrical currents4 ,if a magnetic bar is freely suspended above the earth1 it takes1 in virtue of some terrestrial power1 a given direction1 which is an indication of the earth's magnetic force4 ,whether this is the consequence of the currents of electricity1 which ,ampre supposes to circulate around the globe1 from east to west1 or the result of points of attraction in the earth itself1 the phenomenon is equally wonderful4 ,to whatever cause we may refer the visible effects1 it appears certain that this earth is composed of particles in a magnetic state1 the character varying with physical conditions1 and that terrestrial magnetic force is the collective action of all the atoms of this planetary mass4#agd ,the remarkable connexion which has been observed between the changes in the physical condition of the surface of the sun and terrestrial phenomena1 must not escape our notice4 ,sir ,william ,herschel thought he perceived a link connecting the dark spots on the sun's face with the variations of the earth's temperature4 ,this has not1 however1 been confirmed by the observations which have been made since the time of ,herschel4 ,the careful examinations of the solar spots which have been made by ,schwabe1#age prove a well-defined order of progress in them4 ,he has discovered that they move in cycles of ten years--from the smallest number visible in a given year1 they regularly increase for five years1 when they reach their maximum2 they then as regularly decrease1 and at the end of another five years they are at their maximum number4 ,the magnetic observations which have been carried on by the ,british and other governments for some years1 over every part of the world1 have elicited the fact that the order of variation in the earth's magnetic intensity is in cycles of ten years1 and the law of increase and decrease which is found to prevail with the solar spots distinctly marks the variations of terrestrial magnetism4 ,few more interesting facts than this are within the range of our knowledge1 proving as it does the direct dependence of terrestrial phenomena on solar force4 ,the constancy with which a magnetised needle points along a certain line which varies a little from the earth's axial line1 renders it one of the most important instruments to the practical and the scientific man4 ,the wanderer of the ocean or of the desert is enabled1 without fear of error1 to pursue his path1 and in unknown regions to determine the azimuth of objects4 ,the miner or the surveyor finds in the magnetic compass the surest guide in his labours1 and the experiment is for ever studying its indications4 8,true as the needle to the pole10 has passed into a proverb among mankind1 but the searching inquiry of modern observers has shown that the expression is correct only with certain limitations4 ,there are two lines on the surface of the earth along which the needle points true north1 or where the magnetic and the geographical north correspond4 ,these are called lines of no variation1 or1 as they have also been designated1 agonic lines1 and one is found in the eastern and the other in the western hemisphere4 ,the ,american line is singularly regular1 passing in a south-east direction from the latitude #fj to the west of ,hudson's ,bay1 across the ,american lakes1 till it reaches the ,south ,atlantic ocean1 and cuts the meridian of ,greenwich in about #fe south latitude4 ,the ,asiatic line of no variation is very irregular1 owing1 without doubt1 to local interferences2 it begins below ,new ,holland1 in latitude #fj south1 it bends westward across the ,indian ocean1 and from ,bombay has an inflection eastward through ,china1 and then northward across the sea of ,japan1 till it reaches the latitude of #ga north1 when it descends again southward1 with an immense semicircular bend1 which terminates in the ,white ,sea4 ,hansteen has thought that there are two points in each hemisphere which may be regarded as stronger and weaker poles on opposite sides of the poles of revolution4 ,these are called the magnetic poles of the earth1 or by ,hansteen magnetic points of convergence4 ,these four points are considered to have a regular motion round the globe1 the two northern ones from west to east1 and the two southern ones from east to west4 ,by the assistance of recorded observations1 ,hansteen has calculated the periods of these revolutions to be as follows3-- ,the weakest north pole in #hfj years4 ,the strongest north pole in #agdf years4 ,the weakest south pole in #acjd years4 ,the strongest south pole in #dfji years4 ,there are some points of speculation on which ,hansteen has ventured which have been smiled at as fanciful2 but they may rather indicate an amount of knowledge in the ,brahminical and ,egyptian priesthood1 beyond what we are usually disposed to allow them1 and prove that their observations of nature had led them to an appreciation of some of the most remarkable harmonies of this mysterious creation4 ,the above terms are exceedingly near #hfd1 #abdf1 #agbh1 #dcbj1 and those numbers are equal to the mystic number of the ,indians1 ,greeks1 and ,egyptians1 #dcb multiplied by #b1 #c1 #d1 and #aj4 ,on these the ancients believed a certain combination of natural events to depend1 and1 according to ,brahminical mythology1 the duration of the world is divided into four periods1 each of #dcb1jjj years4 ,again1 the sun's mean distance from the earth is #baf radii of the sun1 and the moon's mean distance #baf radii of the moon1 each the half of #dcb4 ,proceeding with this very curious examination1 ,hansteen says1 #fj multiplied by #dcb equals #ae1ibj1 the smallest number divisible at once by all the four periods of magnetic revolution1 and hence the shortest time in which the four poles can complete a cycle1 and return to their present state1 and which coincides exactly with the period in which the precession of the equinoxes will amount to a complete circle1 reckoning the precession at a degree in seventy-two years4#agf ,when we consider the phenomena of terrestrial magnetism carefully1 it appears to indicate the action of a power external to the earth itself1 and1 as ,hansteen conceives1 having its origin from the action of the sun1 heating1 illuminating1 and producing a magnetic tension1 in the same manner as it produces electrical excitation and actino-chemical action4 ,the movements of these magnetic poles have been the subject of extensive and most accurate observation in every quarter of the globe4 ,in ,london1 during #afeg-affb1 there was no magnetic variation2 the agonic line passing through it4 ,the variation steadily increased1 until1 in #ahae1 it amounted to #bd #ae' #ag1 since which time it has been slowly diminishing4 ,in addition to this great variation1 we have a regular annual change dependent on the position of the sun1 in reference to the equinoctial and solstitial points1 which was discovered by ,cassini1 and investigated by ,arago and others4 ,also a diurnal variation1 which movement appears to commence early in the morning1 moving eastward until half-past seven1 ,a4,m41 when it begins to move westward until two1 ,p4,m41 when it again returns to the east1 and in the course of the night reaches the point from which it started twenty-four hours before4 ,we have also remarkable variations in what is termed the dip of the needle4 ,it is well known that a piece of unmagnetized steel1 if carefully suspended by its centre1 will swing in a perfectly horizontal position1 but1 if we magnetize this bar1 it will immediately be drawn downwards at one end4 ,the force of the earth's polarity1 attracting the dissimilar pole1 has caused it to dip4 ,there is1 in the neighbourhood of the earth's equator1 and cutting it at four points1 an irregular curve1 called the magnetic equator1 or aclinic line1 where the needle balances itself horizontally4 ,as we proceed from this line towards either pole the dip increases1 until1 at the north and south poles1 the needle takes a vertical position4 ,the intensity of the earth's magnetism is also found to vary with the position1 and to increase in a proportion which corresponds very closely with the dip4 ,but the intensity is not a function of the dip1 and the lines of equal intensity1 isodynamic lines1 are not parallel to those of equal dip4 ,we have already remarked on the diurnal variation of the declination of the needle2 we know1 also1 that there exists a regular monthly and daily change in the magnetic intensity4 ,the greatest monthly change appears when the earth is in its perihelion and aphelion1 in the months of ,december and ,june1--a maximum then occurs2 and about the time of the equinoxes a minimum is detected4#agg ,the daily variation of intensity is greatest in the summer1 and least in the winter4 ,the magnetism is generally found to be at a minimum when the sun is near the meridian2 its intensity increasing until about six o'clock1 when it again diminishes4#agh ,what striking evidences all these well-ascertained facts give of the dependence of terrestrial magnetism on solar influence6 and in further confirmation of this view1 we find a very remarkable coincidence between the lines of equal temperature--the isothermal lines1 and those of equal dip and magnetic intensity4 ,sir ,david ,brewster first pointed out that there were in the northern hemisphere two poles of maximum cold2 these poles agree with the magnetic points of convergence2 and the line of maximum heat1 which does not run parallel to the earth's equator1 is nearly coincident with that of magnetic power4 ,since ,seebeck has shown us that electrical and magneto-electrical phenomena can be produced by the action of heat upon metallic bars1 we have1 perhaps1 approached towards some faint appreciation of the manner in which the solar calorific radiations may1 acting on the surface of our planet1 produce electrical and magnetic effects4 ,if we suppose that the sun produces a disturbance of the earth's electricity along any given line1 in all directions at right angles to that line1 we shall have magnetic polarity induced4#agi ,that such a disturbance is regularly produced every time the sun rises1 has been sufficiently proved by many observers4 ,in #agej1 ,wargentin noticed that a very remarkable display of ,aurora borealis was the cause of a peculiar disturbance of the magnetic needle2 and ,dr4 ,dalton#ahj was the first to show that the luminous rays of the ,aurora are always parallel to the dipping-needle1 and that the ,auroral arches cross the magnetic meridian at right angles4 ,hansteen and ,arago have attended with particular care to these influences of the northern lights1 and the results of their observations are3-- ,that as the crown of the ,aurora quits the usual place1 the dipping-needle moves several degrees forward3-- ,that the part of the sky where all the beams of the ,aurora unite1 is that to which a magnetic needle directs itself1 when suspended by its centre of gravity3-- ,that the concentric circles1 which show themselves previously to the luminous beams1 rest upon two points of the horizon equally distant from the magnetic meridian2 and that the most elevated points of each arch are exactly in this meridian4#aha ,it does not appear that every ,aurora disturbs the magnetic needle2 as ,captains ,foster and ,back both describe very splendid displays of the phenomenon1 which did not appear to produce any tremor or deviation upon their instruments4#ahb ,some sudden and violent movements have been from time to time observed to take place in suspended magnets2 and since the establishment of magnetic observatories in almost every part of the globe1 a very remarkable coincidence in the time of these agitations has been detected4 ,they are frequently connected with the appearance of ,aurora borealis2 but this is not constantly the case4 ,these disturbances have been called magnetic storms2 and over the ,asiatic and ,european continent1 the islands of the ,atlantic and the western hemisphere1 they have been proved to be simultaneous4 ,from observations made at ,petersburg by ,kupffer1 and deductions drawn from the observations obtained by the ,magnetic ,association1 it appears probable that these storms arise from a sudden displacement in the magnetic lines of the earth's surface2 but the cause to which this may be due is still to be sought for4 ,in the brief and hasty sketch which has been given of the phenomena of terrestrial magnetism1 enough has been stated to show the vast importance of this very remarkable power in the great operations of nature4 ,we are gradually reducing the immense mass of recorded observations1 and arriving at certain laws which are found to prevail4 ,still1 the origin of the force1 whether it is strictly electrical1 whether it is the circulation of a magnetic fluid1 or whether it is merely a peculiar excitation of some property of matter1 are questions which are open for investigation4 ,in the beautiful ,aurora borealis1 with its trembling diffusive lights1 and its many-coloured rays1 we have what may be regarded as a natural exhibition of magnetism1 and we appear to have within our grasp the explanation we desire4 ,but we know not the secret of even these extraordinary meteorological displays4 ,if we pass an electric spark from a machine through a long cylinder1 exhausted of air as far as possible1 we have a mimic representation of the ,northern ,lights--the same attenuation of brightness1 almost dwindling into phosphorescence2 and by the slightest change of temperature we may produce that play of colours which is sometimes so remarkably manifested in ,aurora4 ,dr4 ,dalton considered ,aurora borealis as a magnetic phenomenon1 and that its beams are governed by the earth's magnetism4 ,we know that the arc of light produced between the poles of a powerful galvanic battery is readily deflected by a good magnet2 and we have lately learned that every vapour obeys the magnetic force4#ahc ,it is1 therefore1 yet a question for our consideration1 does the earth's magnetism produce the peculiar phenomena of ,aurora by acting upon electricity in a state of glow8 or have we evidence in this display of the circulation of the magnetic fluid around our globe1 manifesting itself by its action on the ferruginous and other metallic matter1 which ,fusinieri has proved to exist in the upper regions of our atmosphere4#ahd ,that magnetic radiations do exist1 has been proved by ,faraday1 and that they form lines of force perpendicular to the earth's surface1 has been experimentally shown4 ,parallelograms of wire moved upon a central axis1 and connected with a galvanometer1 give at every revolution indication of an electric disturbance in all respects analogous to the production of a current by moving wires in front of a steel magnet4 ,the alteration in the properties of heat1 when it passes from the radiant state into combination with matter1 exhibits to us something like what we may suppose occurs in the conversion of magnetism into electricity or the contrary4 ,we have a subtile agent1 which evidently is for ever busy in producing the necessary conditions of change in this our earth3 an element to which is due the development of many of the most active powers of nature2 performing its part by blending with those principles which we have already examined2 associating itself with every form of matter2 and giving1 as we shall presently see1 in all probability1 the first impulses to combination1 and regulating the forms of aggregating particles4 ,as electricity has the power of altering the physical conditions of the more adherent states of matter1 thus giving rise to variations of form and modes of combination1 so gross matter appears to alter the character of this agency1 and thus disposes it to the several modifications under which we have already detected its presence4 ,we have mechanical electricity and chemical electricity1 each performing its great work in nature2 yet both manifesting conditions so dissimilar1 that tedious research was necessary before they could be declared identical4 ,magnetic electricity is a third form2 all its characteristics are unlike the others1 and the office it appears to perform in the laboratory of creation is of a different order from that of the other states of electrical force4 ,in the first two we have decomposing and recombining powers constantly manifested--in fact1 their influences are always of a chemical character2 but in the last it appears we have only a directive power4 ,it was thought that evidence had been detected of a chemical influence in magnetism2 it did appear that sometimes a retarding force was exerted1 and often an accelerating one4 ,this has been again denied1 and we have arrayed in opposition to each other some of the first names among ,european experimentalists4 ,the question is not yet to be regarded as settled2 but1 from long and tedious investigation1 during which every old experiment has been repeated1 and numerous new ones tried1 we incline to the conclusion that chemical action is not directly affected by magnetic power4 ,it is highly probable that magnetism may1 by altering the structural arrangement of the surface1 vary the rate of chemical action2 but this requires confirmation4#ahe ,there is no substance to be found in nature existing independently of magnetic power4 ,but it influences bodies in different ways3 one set acting with relation to magnetism1 like iron1 and arranging themselves along the line of magnetic force1--these are called magnetic bodies2 another set1 of which bismuth may be taken as the representative1 always placing themselves at right angles to this line1--these are called diamagnetic bodies4#ahf ,this is strikingly shown by means of powerful electro-magnets2 but the magnetism of the earth is sufficient1 under proper care1 to exhibit the phenomena4 ,every substance in nature is in one or other of these conditions4 ,the rocks1 forming the crust of the earth1 and the minerals which are discovered in them2 the surface soil1 which is by nature prepared as the fitting habitation of the vegetable world1 and every tree1 shrub1 and herb which finds root therein1 with their carbonaceous matter1 in all its states of wood1 leaf1 flower1 and fruit2 the animal kingdom1 from the lowest monad through the entire series up to man1--have1 all of them1 distinct magnetic or diamagnetic relations4 8,it is a curious sight10 says ,dr4 ,faraday1 8to see a piece of wood or of beef1 or an apple1 or a bottle of water repelled by a magnet1 or1 taking the leaf of a tree1 and hanging it up between the poles1 to observe it take an equatorial position4 ,whether any similar effects occur in nature among the myriads of forms which1 upon all parts of its surface1 are surrounded by air1 and are subject to the action of lines of magnetic force1 is a question which can only be answered by future observation40#ahg ,at present1 the bodies which are known to exhibit decided ferro-magnetic properties are the following1 which stand arranged in the order of their intensity3-- ,iron1 ,nickel1 ,cobalt1 ,manganese1 ,chromium1 ,cerium1 ,titanium1 ,palladium1 ,platinum1 ,osmium4 ,it is interesting to know that there are evidences that two bodies which1 when separate1 are not magnetic1 as iron is1 become so when combined4 ,copper and zinc are both of the diamagnetic class1 but many kinds of brass are discovered to be magnetic4 ,the salts of the above metals are1 to a greater or less extent1 ferro-magnetic1 but they may be rendered neutral by water1 which is a diamagnetic body1 being repelled by the magnet4 ,it will be unnecessary1 here1 to enumerate the class of bodies which are diamagnetic2 indeed1 all not included in the preceding list may be considered as belonging to that class1 with the exception of gases and vapours1 which appear to exist1 relatively to each other1 sometimes in the one1 and sometimes in the other condition4#ahh ,to endeavour to reduce our knowledge of these facts to some practical explanation1 we must bear in mind that particular spaces around the north and south geographical poles of the earth1 are regarded as circles to which all the magnetic lines of force converge4 ,under circumstances which should prevent any interference with what is called ferro-magnetic action1 all bodies coming under that class would arrange themselves according to the laws which would regulate the disposition of an infinite number of magnets1 free to move within the sphere of each other's influence4 ,the north and south pole of one magnetic body would attach itself to the south and north pole of another1 until we had a line of magnets of any extent2 the two ends being in opposite states1 like the magnetic points of convergence of the earth4 ,every body1 not ferro-magnetic1 places itself across such a line of magnetic force as we have conceived2 and if the earth were made up of separate layers of ferro-magnetic and diamagnetic bodies1 the result would be the formation of bands at right angles to each other4 ,this is not the case1 by reason of the intermingling of the two classes of substances4 ,out of the known chemical elements we find only about ten which are actively ferro-magnetic2 the others combining with these give rise to either a weaker state1 a neutral condition1 or the balance of action is turned to the diamagnetic side4 ,sulphate of iron1 for instance1 is a magnetic salt2 but in solution1 water being diamagnetic1 it loses its property4 ,the yellow prussiate of potash dissolved in water is a diamagnetic body2 but the red prussiate1 which contains an atom less of potassium1 is magnetic3 but in the solid state they are both diamagnetic4#ahi ,from this it would appear that the chemical composition of a body regulated its relation to magnetism4 ,the following facts will show1 however1 that the molecular structure is more particularly concerned in determining the molecular condition of substances4 ,m4 ,plcker1 being desirous of finding the extent to which the direction of the fibres in organic bodies might influence their magnetic or diamagnetic properties1 was led to inquire whether in crystals the direction of the optic axes1 which itself depends upon the arrangement of the particles1 might not also exercise some influence4 ,the first submitted to the action of the electro-magnet a thin plate of tourmaline1 such as is employed in experiments upon polarization1 having its optic axis parallel to its longest length4 ,it was very quickly perceived that the plate was magnetic1 by the effect of the iron that it contains2 but it was suspended successively in three ways1--first1 so that its longest side was vertical1 then as that the shortest side was vertical1 and finally so that the plate itself was horizontal4 ,in the first case it is directed between the two points of the conical curvatures of the poles like a magnetic body2 but1 in the other two cases1 on the contrary1 it took the direction assumed by diamagnetic bodies--that is to say1 a direction such that its longest length was perpendicular to the line joining the poles4 ,this direction indicated that the optical axis was repelled by the two poles1 and that this repulsion outweighed the magnetic properties of the crystal4#aij ,the relation of structure to physical phenomena of essentially different characters is remarkable4 ,savart1 when making crystalline plates of quartz and carbonate of lime vibrate1 succeeded in determining a relation between the acoustic figures that are produced in them1 and the particular mode of the crystallization of the substance4 ,he found that the direction of the optical axis is constantly connected with that of the principal forms of the acoustic figures4 ,mitscherlich has remarked that crystals do not expand uniformly by heat1 but that this dilatation is greater in one direction than in another2 and that this difference is connected with their crystalline form4 ,m4 de ,snarmont has shown that conductibility for heat1 which is equal in all directions for the crystals of the regular system1 acquires in others a maximum or a minimum value1 according to directions parallel to the crystallographic axes2 so that the isothermic surfaces1 which are spheres in the former case1 are1 in the other1 ellipsoids elongated or flattened in the same direction4 ,the optical axes do not altogether coincide with the principal axes of conductibility for heat2 but this appears to be due merely to slight differences in the rate of progression1 or the refrangibility of the luminous and calorific rays4 ,wiedemann1 by employing a fine point through which he made electricity arrive upon a surface that he had powdered with licopodium or red lead1 succeeded in determining1 by means of the form assumed by this light powder1 the conductibility of crystals in different directions4 ,on a surface of glass1 the powder which disperses itself around the points1 in consequence of electric repulsion1 forms a circular figure traversed by radii4 ,when a plate of gypsum is used instead of glass the figure is found to be elliptical1 and the great axis of the ellipse forms a right angle with the principal crystallographic axis1 which proves that the electricity distributes itself more easily in a direction perpendicular to the axis than in any other4 ,m4 ,wiedemann comes to the conclusion that crystals which possess a better conductibility in the direction of the principal axis1 all belong to the class of negative crystals3 while those which have a better conductibility in the direction perpendicular to the axis are positive1 which indicates that the direction of best conductibility for electricity is also that according to which light is propagated relatively with greater velocity4 ,tyndale has shown1 that if gutta percha which has been rendered fibrous in manufacture is cut so that the fibres are in the direction of this greatest length1 or in a direction perpendicular to this greatest length1 and placed under the influence of a magnet1 they direct themselves equatorially4 ,ivory cut in the same direction manifests the same conditions1 though both these substances are diamagnetic4 ,the fibrous structure1 and the planes of cleavage1 thus determine the magnetic condition of a substance4 ,the special properties presented by crystals1 in regard to the action exercised upon them by magnets1 is due to a particular mode of grouping their particles4 ,this is also the cause of unequal dilatability1 and of unequal conductibility for heat and for electricity4 ,how curiously1 therefore1 does molecular structure determine the relation of a body to any of the forms of physical force6 ,we still search in the dark1 and see but dimly the evidences2 yet it becomes almost a certainty to us1 that this stone of granite1 with its curious arrangement of felspar1 mica1 and quartz1 presents its peculiar condition in virtue of some law of magnetic force4 ,the crystal1 too1 of quartz1 which we break out of the mass1 and which presents to us a beautifully regular figure1 is1 beyond a doubt1 so formed1 because the atoms of silica are each one impelled in obedience to one of these two conditions of magnetism to set themselves in a certain order to each other1 which cannot be altered by human force without destruction4 ,all the laws which regulate the forms of crystals and amorphous bodies are1 to the greatest degree1 simple4 ,in nature the end is ever attained by the easiest means2 and the complexity of operation1 which appears sometimes to the observer1 is only so because he cannot see the spring by which the machine is moved4 ,the gaseous envelope1 our atmosphere1 is in a neutral state4 ,oxygen is strikingly magnetic in relation to hydrogen gas1 whilst nitrogen is as singularly the contrary2 and the same contrasts present themselves when these gases are examined in their relation to common air4 ,thus1 oxygen being magnetic1 and nitrogen the contrary1 we have an equilibrium established1 and the result is a compound neutral in its relations to all matter4 ,all gases and vapours are found to be diamagnetic1 but in different degrees4#aia ,this is shown by passing a stream of the gas1 rendered visible by a little smoke1 within the influence of a powerful magnet4 ,these bodies are1 however1 found relatively to each other1--or even to themselves1 under different thermic conditions1--to change their states1 and pass from the magnetic to the diamagnetic class4 ,heat has a very remarkable influence in altering these relations2 and atmospheric air at one temperature is magnetic to the same fluid at another3 thus1 by thermic variations1 attraction or repulsion may be alternately maintained4 ,by this it must be understood that a stream of air1 at a temperature elevated but a few degrees above that of an atmosphere of the same kind into which it is passing1 is deflected in one way by a magnet2 whereas1 if the stream is colder than the bulk through which it flows1 it is bent in another way by the same force4 ,in this respect magnetism and diamagnetism show equally the influence of another physical force1 heat2 and we may safely refer many meteorological phenomena to similar alterations of condition in the atmosphere1 relative to the magnetic relations of the arial currents4 ,that magnetism has a directive power is satisfactorily shown by the formation of crystals in the neighbourhood of the poles of powerful magnets4 ,the common iron salt1 the protosulphate1 ordinarily crystallizes so that the crystals unite by their faces2 but when crystallizing under magnetic influence1 they have a tendency to arrange themselves with regard to each other so that the acute angle of one crystal unites with one of the faces of another crystal1 near to1 but never actually at1 its obtuse angle4 ,in addition to this1 if a magnet of sufficient power is employed1 the crystals arrange themselves in magnetic curves from one pole to the other1 a larger crop of crystals being always formed at the north than at the south pole4 ,here we have evidence of an actual turning round of the crystal1 in obedience to the directive force of the magnet2 and we have the curious circumstance of a difference in some way1 which is not clearly explained1 between the two opposite poles4 ,if1 instead of an iron or a ferro-magnetic salt1 we employ one which belongs to the other1 or diamagnetic1 class1 we have a curious difference in the result4 ,if into a glass dish1 fixed on the poles of a strong electro-magnet1 we pour a quantity of a solution of nitrate of silver1 and place in the fluid1 over the poles of the magnet1 two globules of mercury 7an arrangement by which that arborescent crystallization1 called the ,arbor ,dian1 is produced17 we have the long needle-shaped crystals of silver1 arranging themselves in curves which would cut the ordinary magnetic lines at right angles4#aib ,in the first example given we have an exhibition of magnetic force1 while in the last we have a striking display of the diamagnetic power4 ,the large majority of natural formations appear to group themselves under the class of diamagnetics4 ,these bodies are thought to possess poles of mutual repulsion among themselves1 and which are equally repelled by the magnetic points of convergence4 ,confining our ideas to single particles in one condition or the other1 we shall1 to a certain extent1 comprehend the manifold results which must arise from the exercise of these two modes of force4 ,at present1 our knowledge of the laws of magnetism is too limited to allow of our making any general deductions relative to the disposition of the molecules of matter2 and the amount of observation which has been given to the great natural arrangements1 is too confined to enable us to infer more than that it is probable many of the structural conditions of our planet are due to polarity4 ,mountain ranges observe a singular uniformity of direction1 and the cleavage planes of rock are evidently determined by some all-pervading power4 ,mineral bodies are not distributed in all rocks indiscriminately4 ,the primary formations hold one class of metalliferous ores1 and the more recent ones another4 ,this is not to be regarded as in any way connected with their respective ages1 but with some peculiar condition of the stone itself4 ,the granite and slate rocks1 at their junctions1 present the required conditions for the deposit of copper ore1 while we find the limestones have the characteristic physical state for accumulating lead ore4 ,again1 on examining any mineral vein1 it will be at once apparent that every particle of ore1 and every crystal of quartz or limestone1 is disposed in a direction which indicates the exercise of some powerful directive agency4#aic ,it appears1 from all the results hitherto obtained1 that the magnetic and diamagnetic condition of bodies is equally due to some peculiar property of matter in relation to the other forms of electricity4 ,we have not yet arrived at the connecting link1 but it does not appear to be far distant4 ,we have already referred to the statement made by talented experimentalists1 that magnetism has a powerful influence in either retarding or accelerating chemical combination4 ,beyond a doubt chemical action weakens the power of a magnet2 but the disturbance which it occasions in soft iron1 on the contrary1 appears to tend to its receiving magnetism more readily1 and retaining it more permanently4 ,further investigations are1 however1 required1 before we can decide satisfactorily either of these problems1 both of which bear very strongly upon the subject we have just been considering4 ,we have seen that heat and electricity act strangely on magnetic force1 and that this statical power reacts upon them3 and thus the question naturally arises1 ,do light and magnetism in any way act upon each other8 ,morichini and ,carpi on the continent1 and ,mrs4 ,somerville in ,england1 have stated that small bars of steel can be rendered magnetic by exposing them to the influence of the violet rays of light4 ,these results have been denied by others1 but again repeated and apparently confirmed4 ,in all probability1 the rays to which the needles were exposed1 being those in which the maximum actinic power is found1 produced an actual chemical change2 and then1 if the position were favourable1 it is quite evident that magnetism would be imparted4 ,indeed we have found this to be the case when the needles1 exposed to solar radiations1 were placed in the direction of the dip4 ,the supposed magnetization of light by ,faraday has already been mentioned4 ,if the influence in one case is determined1 it will render the other more probable4#aid 8,in seeking for a cause10 writes ,sir ,david ,brewster1 8which is capable of inducing magnetism on the ferruginous matter of our globe1 whether we place it within the earth1 or in its atmosphere1 we are limited to the ,,sun1 to which all the magnetic phenomena have a distinct reference2 but1 whether it acts by its heat1 or by its light1 or by specific rays1 or influences of a magnetic nature1 must be left to future inquiry40#aie ,we have learnt that magnetism is not limited to ferruginous matter2 we know that the ancient doctrine of the universality of the property is true4 ,kircher1 in his strange work on ,magnetism1 published in the early part of the seventeenth century#aif--;a curious exemplification of the most unwearying industry and careful experiment1 combined with the influences of the credulity and superstitions of his age--attributes to this power nearly all the cosmical phenomena with which1 in his time1 men were acquainted4 ,he curiously anticipates the use of the supposed virtue of magnetic traction in the curative art2 and as the titles of his concluding chapters sufficiently show1 he was a firm believer in animal magnetism4#aig ,but it is not with any reference to these that we refer to the work of ,athanasii ,kircheri1 ,societatis ,jesu1 ,magnes1 sive de ,magnetiv ,arte1 but to show that two hundred years since1 man was near a great truth2 but the time of its development being not yet come1 it was allowed to sleep for more than two centuries1 and the shadow of night had covered it4 ,in speaking of the vegetable world1 and the remarkable processes by which the leaf1 the flower1 and the fruit are produced1 this sage brings forward the fact of the diamagnetic character of the plant1 which has been1 within the last two years1 re-discovered2 and he refers the motions of the ,sun-flower1 the closing of the ,convolvulus1 and the directions of the spiral1 formed by twining plants1 to this particular influence4 ,this does not appear as a mere speculation1 a random guess1 but is the result of deductions from experiment and observation4 ,kircher doubtless leaped over a wide space to come to his conclusion2 but the result is valuable in a twofold sense4 ,in the first it shows us that1 by neglecting a fact which is suggestive1 we probably lose a truth of great general application2 and secondly1 it proves to us1 that by stepping beyond the point to which inductive logic leads1 and venturing on the wide sea of hypothesis1 we are liable to sacrifice the true to the false1 and thus to hinder the progress of human knowledge4 ,magnetism1 in one or other of its forms1 is now proved to be universal1 and to its power we are disposed to refer the structural conditions of all material bodies1 both organic and inorganic4 ,this view has scarcely yet been recognised by philosophers2 but as we find a certain law of polarity prevailing through every atom of created matter1 in whatever state it may be presented to our senses1 it is evident that every particle must have a polar and directing influence upon the mass1 and every coherent mass becomes thus only a larger and more powerful representative of the magnetic unit4 ,thus we see the speculation of ,hansteen1 that the sun is1 to us1 a magnetic centre1 and that it is equally influenced by the remoter suns of the universe1#aih is supported by legitimate deductions from experiment4 ,the great difficulty is not1 however1 got rid of by this speculation2 the cause by which the earth's magnetism is induced is only removed further off4 ,the idea of a magnetic fluid is scarcely tenable2 and the ferruginous nature of the ,aurora borealis receives no proof from any investigation2 indeed1 we have procured evidence to show that iron is not at all necessary for the production of magnetic phenomena4 ,the leaf of a tree1 a flower1 fruit1 a piece of animal muscle1 glass1 paper1 and a variety of similar substances1 have the power of repelling the bar of iron which we call a magnet1 and of placing it at right angles to the direction of the force exerted by them4 ,this is a point which must be constantly borne in mind when we now consider the mysteries of magnetic phenomena4 ,any two masses of matter act upon each other according to this law1 and although by the power of cohesion the force may be brought to an equilibrium1 or to its zero point1 it is never lost1 and may be readily and rapidly manifested by any of the means employed for electrical excitation4 ,reasoning by analogy1 the question fairly suggests itself3 ,if two systems of inorganic atomic constitution are thus invested with a power of influencing each other through a distance1 why may not two more highly developed organic systems equally1 or to a greater extent1 produce an influence in like manner8 ,upon such reasoning as this is founded the phenomenon known as ,animal ,magnetism4 ,there is no denying the fact that one mass of blood1 muscle1 nerves1 and bone1 must1 magnetically1 influence another similar mass4 ,this is1 however1 something totally different from that abnormal condition which is produced through some peculiar and1 as yet1 unexplained physiological influences4 ,with the mysterious operations of vital action1 the forces which we have been considering have nothing whatever in common4 ,the powers which are employed in the arrangements of matter are1 notwithstanding their subtile character1 of far too gross a nature to influence the psychological mysteries which present themselves to the observant mind4 ,it cannot be denied that1 by placing a person of even moderate nervous sensibility in a constrained position1 and under an unnatural influence of the mind1 as acquired by the disciples of ,mesmer1 a torpor affecting only certain senses is produced4 ,the recognised and undoubted phenomena are in the highest degree curious--but in these the marvels of charlatanry and ignorance are not included2--and the explanation must be sought for by the physiologist among those hidden principles upon which depends all human sensation4#aii ,man1 like a magician1 stands upon a promontory1 and surveying the great ocean of the physical forces which involve the material creation1 and produce that infinite variety of phenomena which is unceasingly exhibited around him1 he extends the wand of intelligence1 and bids the 8spirits of the vasty deep0 obey his evocation4 ,the phenomena recur--the great processes of creation go on--the external manifestations of omnipotent power proceed--effects are again and again produced2 but the current of force passes undulating onwards2--and to the proud bidding of the evocator there is no reply but the echo of his own vain voice1 which is lost at last in the vast immensity of the unknown which lies beyond him4 ,we see how powerfully the physical forces1 in their various modes of action1 stir and animate this planetary mass2 and amongst these the influence of magnetism appears as a great directing agent1 though its origin is unknown to us4 ,that power which1 like a potent spirit1 guides ,the sea-wide wanderers over distant tides1 ,inspiring confidence where'er they roam1 ,by indicating still the pathway home2-- ,through nature1 quicken'd by the solar beam1 ,invests each atom with a force supreme1 ,directs the cavern'd crystal in its birth1 ,and frames the mightiest mountains of the earth2 ,each leaf and flower by its strong law restrains1 ,and binds the monarch ,man within its mystic chains4 ,,footnotes3 #agj ,treatise on ,magnetism1 by ,sir ,david ,brewster4 ,cosmos3 a ,sketch of a ,physical description of the ,universe2 by ,alexander ,von ,humboldt4--,ott's ,translation4 #aga ,exprience ,electro-,magntique4 par ,m4 rsted4--,annales de ,chimie1 vol4 xxii4 p4 #bja4 ,de la ,rive1 ,recherches sur la ,distribution de l',electricit dyn4 dans les ,corps4--,genve1 #ahbe4 #agb ,on the ,magnetic power of ,soft ,iron3 by ,mr4 ,watkins4--,philosophical ,transactions1 #ahcc4 #agc ,cavallo1 ,on ,magnetism4--,cavallo was the first who noticed the influence of heat on ,magnetism4 ,consult ,on the anomalous ,magnetic ,action of ,hot ,iron between the white and blood-red heat3 by ,peter ,barlow1 ,esq4--,philosophical ,transactions1 #ahbb1 p4 #abd4 ,treatise on ,magnetism3 by ,barlow4--,encyclopdia ,metropolitana4 #agd 8,the foundation of our researches is the assumption that the terrestrial magnetic force is the collective action of all the magnetised particles of the earth's mass4 ,we represent to ourselves magnetisation as the separation of the magnetic fluids4 ,admitting the representation1 the mode of action of the fluids 7repulsion of similar1 and attraction of dissimilar1 particles inversely as the square of the distance7 belongs to the number of established truths4 ,no alteration in the results would be caused by changing this mode of representation for that of ,ampre1 whereby1 instead of magnetic fluids1 magnetism is held to consist in constant galvanic currents in the minutest particles of bodies4 ,nor would it occasion a difference if the terrestrial magnetism were ascribed to a mixed origin1 as proceeding partly from the separation of the magnetic fluids in the earth1 and partly from galvanic currents1 in the same2 inasmuch as it is known that for each galvanic current may be substituted such a given distribution of the magnetic fluids in a surface bounded by the current1 as would exercise in each point of external space precisely the same magnetic action as would be produced by the galvanic current itself40--,general ,theory of ,terrestrial ,magnetism1 by ,professor ,carl ,friedrich ,gauss1 of the ,university of ,gttingen4--,scientific ,memoirs1 vol4 ii4 p4 #ahh4 #age ,humboldt's ,cosmos4--,ott's translation4 #agf ,hansteen3 ,untersuchungen ber den ,magnetismus der ,erde1 ,christana1 #ahai4 ,humboldt3 ,expos des ,variations ,magntiques4--,gilbert's ,annales4 ,brewster's ,magnetism3 ,encyclopdia ,metropolitana4 #agg ,hansteen2 as above4 #agh ,on the effects of temperature on the intensity of magnetic forces1 and on the diurnal variations of the terrestrial magnetic intensity2 by ,samuel ,hunter ,christie1 ,esq4--,philosophical ,transactions1 vol4 cxv4 #ahbe4 #agi ,it has been observed by ,mr4 ,barlow1 in ,england1 and some eminent observers in ,austria1 that an electric current constantly traverses the wires of the electric telegraph wherever there are two earth connections4 #ahj ,meteorological ,observations and ,essays3 by ,dr4 ,dalton4 ,on the ,height of the ,aurora ,borealis above the surface of the ,earth3 by ,john ,dalton1 ,f4,r4,s4--,philosophical ,transactions1 vol4 cxiv4 p4 #bia4 #aha ,arago3 ,annales de ,chimie1 vol4 xxxix4 p4 #cfi4 ,on the variable ,intensity of ,terrestrial ,magnetism and the ,influence of the ,aurora ,borealis upon it2 by ,robert ,were ,fox4--,philosophical ,transactions1 #ahca1 p4 #aii4 #ahb 8,brilliant and active coruscations of the ,aurora ,borealis10 says ,captain ,back1 8when seen through a hazy atmosphere1 and exhibiting the prismatic colours1 almost invariably affected the needle4 ,on the contrary1 a very bright ,aurora1 though attended by motion1 and even tinged with a dullish red and a yellow in a clear blue sky1 seldom produced any sensible change1 beyond1 at the most1 a tremulous motion4 ,a dense haze or fog1 in conjunction with an active ,aurora1 seemed uniformly favourable to the disturbance of the needle1 and a low temperature was favourable to brilliant and active coruscations4 ,on no occasion during two winters was any sound heard to accompany the motions4 ,the ,aurora was frequently seen at twilight1 and as often to the eastward as to the westward2 clouds1 also1 were often perceived in the day-time1 in form and disposition very much resembling the ,aurora40--,narrative of the ,arctic ,land ,expedition4 #ahc ,faraday3 ,on the ,diamagnetic character of ,flame and ,gases4 #ahd 8,the ,aurora ,borealis is certainly in some measure a magnetical phenomenon2 and if iron were the only substance capable of exhibiting magnetic effects1 it would follow that some ferruginous particles must exist in the upper regions of the atmosphere4 ,the light usually attending this magnetical meteor may possibly be derived from electricity1 which may be the immediate cause of a change in the distribution of the magnetic fluid1 contained in the ferruginous vapours which are imagined to float in the air40--,lecture on ,magnetism3 ,young's ,lectures on ,natural ,philosophy1 p4 #ecc4 #ahe ,on the supposed influence of ,magnetism and ,chemical ,action2 by ,robert ,hunt4--,philosophical ,magazine1 vol4 xxxii4 ,no4 #bae1 #ahdi4 #ahf ,those bodies which are attracted by a magnet1 as iron is1 are called magnetic bodies4 ,those which are1 on the contrary1 repelled by the same power1 are termed diamagnetic bodies4 ,on these ,dr4 ,faraday remarks3--8,of the substances which compose the crust of the earth1 by far the greater portion belong to the diamagnetic class2 and though ferruginous and other magnetic matters1 being more energetic in their action1 are more striking in their phenomena1 we should be hasty in assuming that1 therefore1 they over rule entirely the effect of the former bodies4 ,as regards the ocean1 lakes1 rivers1 and the atmosphere1 they will exert their peculiar effect almost uninfluenced by any magnetic matter in them1 and as respects the rocks and mountains1 their diamagnetic influence is perhaps greater than might be anticipated4 ,i mentioned that by adjusting water and a salt of iron together1 ,i obtained a solution inactive in air2 that is1 by a due association of the forces of a body1 from each class1 water and a salt of iron1 the magnetic force of the latter was entirely counteracted by the diamagnetic force of the former1 and the mixture was neither attracted nor repelled3 ,to produce this effect1 it required that more than #dhf grains of crystallised protosulphate of iron should be added to ten cubic inches of water 7for these proportions gave a solution which would set equatorially71 a quantity so large1 that ,i was greatly astonished on observing the power of the water to overcome it4 ,it is not1 therefore1 at all unlikely that many of the masses which form the crust of this our globe1 may have an excess of diamagnetic power1 and act accordingly40--,on new magnetic actions1 and on the magnetic condition of all matter2 by ,michael ,faraday1 ,d4,c4,l41 ,f4,r4,s41 c4--,philosophical ,transactions1 ,jan4 #ahdf1 vol4 cxxxvii4 p4 #da4 #ahg ,ibid4 #ahh ,on the ,diamagnetic conditions of ,flame and ,gases1 by ,michael ,faraday4 ,f4,r4,s42 and ,on the motions presented by ,flame when under ,electro-,magnetic ,influence1 by ,professor ,zantedeschi4--,philosophical ,magazine1 #ahdg1 pp4 #dja-dba4 #ahi ,on ,diamagnetism2 by ,professor ,plcker1 of ,bonn4--,philosophical ,magazine1 ,july1 #ahdh4 #aij ,for a detailed account of the experiments of ,faraday1 ,plcker1 ,becquerel1 ,tyndale1 and ,knoblauch1 see ,de ,la ,rive's ,treatise on ,electricity in ,theory and ,practice4 #aia ,a few examples taken from ,dr4 ,faraday's paper will show this3-- ,nitrogen being acted on was manifestly diamagnetic in relation to common air when both were of the same temperature4 ,oxygen appears to be magnetic in common air4 ,hydrogen proved to be clearly and even strongly diamagnetic4 ,its diamagnetic state shows1 in a striking point of view1 that gases1 like solids1 have peculiar and distinctive degrees of diamagnetic force4 ,carbonic acid gas is diamagnetic in air4 ,carbonic oxide was carefully freed from carbonic acid before it was used1 and it appears to be more diamagnetic than carbonic acid4 ,nitrous oxide was moderately1 but clearly1 diamagnetic in air4 ,olefiant gas was diamagnetic4 ,the coal gas of ,london is very well diamagnetic1 and gives exceedingly good and distinct results4 ,sulphurous acid gas is diamagnetic in air4 ,muriatic acid gas was decidedly diamagnetic in air4--,on the ,diamagnetic ,conditions of ,flame and ,gases3 ,philosophical ,magazine1 #ahdg1 p4 #dji4 #aib ,for illustration of this ,i must refer to my own ,memoir1 ,researches on the ,influence of ,magnetism and ,voltaic ,electricity on ,crystallization1 and other conditions of matter1 in the ,memoirs of the ,geological ,survey of ,great ,britain1 c41 vol4 i4 #aic ,in a work published by ,mr4 ,evan ,hopkins1 entitled ,on the ,connexion of ,geology with ,terrestrial ,magnetism1 will be found many valuable practical observations made in this country and the gold and silver districts of ,america2 but the views taken by the author are open to many objections4 #aid ,see a notice by ,faraday of ,morichini's ,experiments in ,relations of ,light to ,magnetic ,force--,philosophical ,transactions1 vol4 cxxxvii4 p4 #ae4 ,see also ,mr4 ,christie ,on ,magnetic ,influence in the ,solar ,rays--,philosophical ,transactions1 vol4 cvii4 p4 #bai2 vol4 cxix4 p4 #cgi4 #aie ,sir ,david ,brewster ,on ,magnetism2 republished from the ,encyclopdia ,britannica4 #aif ,the whole of the title of ,kircher's book will convey some idea of the subjects embraced3--,athanasii ,kircheri ,societatis ,jesu ,magnes1 sive de ,arte ,magnetic2 opus tripartitum1 quo ,universa ,magnetis ,natura ejusque in omnibus ,scientiis et ,artibus usus nov methodo explicatur3 ac prterea e viribus et prodigiosis effectibus ,magneticarum aliarumque abditarum ,natur ,motionum in ,elementis1 ,lapidibus1 ,plantis1 ,animalibus elucescentium3 multa hucusque incognita ,natur ,arcana1 per ,physica1 ,medica1 ,chymica1 et ,mathematica omnis generis ,experimenta recluduntur ,editio ,tertia3 ab ipso ,authore recognita emendataque1 ac multis novorum ,experimentorum ,problematibus aucta4 ,rom1 #afed4 #aig ,the following are the titles of the concluding chapters of ,kircher's book3--,de magnetismo solis et lun in maria4 ,de magnetic vi plantarum4 ,de insitionis magneticis miraculis4 ,de magnetismo virgul aurifer seu divinatori4 ,de plantis heliotropiis eorumque magnetismo4 ,de magnetismo rerum medicinalium4 ,de vi attractiv potenti imaginativ4 ,de magnetismo music4 ,de magnetismo amoris4 #aih 8,for these reasons it appears most natural to seek their origin in the sun1 the source of all living activity1 and our conjecture gains probability from the preceding remarks on the daily oscillations of the needle4 ,upon this principle the sun may be conceived as possessing one or more magnetic axes1 which1 by distributing the force1 occasion a magnetic difference in the earth1 in the moon1 and all those planets whose internal structure admits of such a difference4 ,yet1 allowing all this1 the main difficulty seems not to be overcome1 but merely removed from the eyes to a greater distance2 for the question may still be asked1 with equal justice1 whence did the sun acquire its magnetic force8 ,and if from the sun we have recourse to a central sun1 and from that again to a general magnetic direction throughout the universe1 having the ,milky ,way for its equator1 we but lengthen an unrestricted chain1 every link of which hangs on the preceding link1 no one of them on a point of support4 ,all things considered1 the following mode of representing the subject appears to me most plausible4 ,if a single globe were left to move alone freely in the immensity of space1 the opposite forces existing in its material structure would soon arrive at an equilibrium conformable to their nature1 if they were not so at first1 and all activity would soon come to an end4 ,but if we imagine another globe to be introduced1 a mutual relation will arise between the two2 and one of its results will be a reciprocal tendency to unite1 which is designated and sometimes thought to be explained by the merely descriptive word ,attraction4 ,now would this tendency be the only consequence of this relation8 ,is it not more likely that the fundamental forces1 being drawn from their state of indifference or rest1 would exhibit their energy in all possible directions1 giving rise to all kinds of contrary action8 ,the electric force is excited1 not by friction alone1 but also by contact1 and probably also1 though in smaller degrees1 by the mutual action of two bodies at a distance2 for contact is nothing but the smallest possible distance1 and that1 moreover1 only for a few small particles4 ,is it not conceivable that magnetic force may likewise originate in a similar manner8 ,when the natural philosopher and the mathematician pay regard to no other effect of the reciprocal relation between two bodies at a distance1 except the tendency to unite1 they proceed logically1 if their investigations require nothing more than a moving power2 but should it be maintained that no other energy can be developed between two such bodies1 the assertion will need proof and the proof will be hard to find40--,the above is a translation from ,hansteen's work ,on ,magnetism4 #aii ,see article ,animal ,magnetism1 ,encyclopdia ,britannica1 and ,mr4 ,braid's papers ,on ,hypnotism1 published in the 8,medical ,times40 ,,chapter ,,xi4 ,,chemical ,,forces4 ,nature's ,chemistry--,changes produced by ,chemical ,combination--,atomic ,constitution of ,bodies--,laws of ,combination--,combining ,equivalents--,elective ,affinity--,chemical ,decomposition--,compound ,character of ,chemical ,phenomena--,catalysis or action of ,presence--,transformation of ,organic ,bodies--,organic ,chemistry--,constancy of ,combining ,proportions--,the ,law of ,volumes1 the ,law of ,substitutions1 ,isomeric ,states1 c4 ,all things on the earth are the result of chemical combination4 ,the operations by which the commingling of molecules and the interchange of atoms take place1 we can imitate in our laboratories2 but in nature they proceed by slow degrees1 and1 in general1 in our hands they are distinguished by suddenness of action4 ,in nature chemical power is distributed over a long period of time1 and the process of change is scarcely to be observed4 ,by art we concentrate chemical force1 and expend it in producing a change which occupies but a few hours at most4 ,many of the more striking phenomena of nature are still mysterious to us1 and principally because we do not1 or cannot1 take the element time into calculation4 ,the geologist is compelled to do this to explain the progress of the formation of the crust of the earth1 but the chemist rarely regards the effects of time in any of his operations4 ,the chemical change which within the fissure of the rock is slowly and silently at work1 displacing one element or molecule1 and replacing it by another1 is in all probability the operation of a truly geological period4 ,many1 however1 of the changes which are constantly going on around us1 are of a much more rapid character1 and in these nature is no slower in manipulating than the chemist4 ,had it been that the elements which are now found in combination could exist in a free state1 the most disastrous consequences would necessarily ensue4 ,there must have been a period when many of the combinations known to us were not yet created4 ,their elements either existed in other forms1 or were uncombined4 ,our rocks are compounds of oxygen with certain peculiar metals which unite with oxygen so rapidly that incandescence is produced by their combination4 ,let us suppose that any of these metals existed in purity1 and that they were suddenly brought into contact with water1 the atmospheric air1 or any body containing oxygen1 the result would be a convulsion of the most fearful kind2 the entire mass of metal would glow with intensity of heat1 and the impetuosity of the action would only be subdued when the whole of the metal had become oxidized4 ,volcanic action has been referred to some such cause as this1 but there is not sufficient evidence to support the hypothesis2 indeed1 it is contrary to the opinion of most philosophers4#bjj ,such a condition may possibly have existed at one time1 during that period when darkness was upon the face of the deep1 when the earth was a chaos2 but it is only adduced here as an example of the violent nature of some chemical changes4 ,potassium thrown on water bursts into flame1 and sodium does so under certain conditions4 ,if these1 or the metals proper in a state of fine division1 are brought into an atmosphere of chlorine1 the intensity of chemical action is so great that they become incandescent1 many of them glowing with extreme brilliancy4 ,if hydrogen gas is mixed with this element 7chlorine7 they unite1 under the influence of light1 with explosive violence1 giving rise to a compound1 muriatic acid1 which combines with water in an almost equally energetic manner4 ,nitrogen1 as it exists in the atmosphere1 mixed with oxygen1 appears nearly inert2 with hydrogen it forms the pungent compound1 ammonia2 with carbon1 the poisonous one1 cyanogen1 the base of prussic acid2 with chlorine it gives rise to a fluid1 oily in its appearance1 but which1 when merely touched by an unctuous body1 explodes more violently than any other known compound1 shivering whatever vessel it may be contained in1 to atoms2 with iodine it is only slightly less violent2 and in certain combinations with silver1 mercury1 gold1 or platinum1 it produces fulminating compounds of the most dangerous character4#bja ,here we have elements harmless when uncombined1 exhibiting the most destructive effects if their combinations are at all disturbed2 and in the other case we have inert masses produced from active and injurious agents4 ,we regard a certain number of substances as elementary2 that is to say1 not being able1 in the present state of our knowledge1 to reduce them to any more simple condition1 they are considered as the elements which by combination produce the variety of substances found in the three kingdoms of nature4 ,we have already spoken of the atomic constitution of bodies4 ,it remains now to explain the simplicity and beauty which mark every variety of combination under chemical force4 ,as a prominent and striking example1 water is a compound of two gaseous bodies1 oxygen and hydrogen3-- ,if we decompose water by means of galvanic electricity1 or determine its composition by direct chemical analysis1 we shall find it consists of two volumes of hydrogen gas1 united to one volume of oxygen1 or1 by weight1 of one part of hydrogen combined with eight of oxygen4 ,in #ajj parts1 therefore1 we should find-- ,oxygen #hhi ,hydrogen #aaj ,it is found in the same way that the theoretical weight of the atom of carbon is #f1 and that of nitrogen #ad2 whilst the atom of iron is #bh1 that of silver #ajh1 of gold #aii1 and that of platinum and iridium each #ih4bjb ,now1 as these are the relative weights of the ultimate indivisible atom1 it follows that all combinations must be either atom to atom1 or one to two1 three1 or four2 but that in no case should combination take place in any other than a multiple proportion of the equivalent or atomic number4 ,this is found to be the case4 ,oxygen1 for instance1 combines as one1 two1 or three atoms2 its combination presenting some multiple of its equivalent number #h1 as #af1 or #bd3 and in like manner the combining quantity of carbon is #f1 or some multiple of that number4 ,where this law is not found strictly to agree with analytical results1 of which some examples are afforded by the sesquioxides1 it may be attributed1 without doubt1 to some error of analysis or in the method of calculation4 ,nothing can be more perfect than the manner in which nature regulates the order of combination4 ,we have no uncertain arrangement2 but1 however great the number of the atoms of one element may be1 over those of another1 those only combine which are required1 according to this great natural law1 to form the compound1 all the others still remaining free and uncombined4 ,these results certainly appear to prove that the elementary particles of matter are not of the same specific gravities4 ,do they not also indicate that any alteration in the specific gravity of the atom would give rise to a new series of compounds1 thus apparently producing a new element8 ,surely there is nothing irrational in the idea that the influences of heat or electricity1 or of other powers of which as yet we know nothing1 may be sufficient to effect such changes in the atomic constituents of this earth4 ,the combination of elementary atoms takes place under the influence of an unknown force which we are compelled to express by a figurative term1 affinity4 ,in some cases it would appear that the disposition of two bodies to unite1 is determined by the electrical condition2 but a closer examination of the question than it is possible to enter into in this place1 clearly shows that some physical state1 not electrical1 influences combining power4 ,chemical affinity or attraction is the peculiar disposition which one body has to unite with another4 ,to give some instances in illustration4 ,water and spirit combine most readily3 they have a strong affinity for each other4 ,water and oil repel each other3 they have no affinity2 they will not enter into combination4 ,if carbonate of potash is added to the spirit and water in sufficient quantity1 the water is entirely separated1 and the pure spirit will float over the hydrated potash4 ,if potash is added to the oil and water1 it combines with the oil1 and1 forming soap1 they all unite together2 but1 if we now add a little acid to the mixture1 the potash will quit the oil to combine with the acid1 and the oil will be repelled as before and float on the liquid4 ,this has been called single elective affinity4 ,these elections were regarded as constant1 and chemists drew up tables for the purpose of showing the order in which these decompositions occur4#bjc ,thus1 ammonia1 it was shown1 would separate sulphuric acid from magnesia1 lime remove it from ammonia1 potash or soda from lime1 and barytes from potash or soda4 ,it was thought the inverse of this order would not take place1 but recent researches have shown that the results are modified by quantity and some other conditions4 ,it often happens that we have a compound action of this kind in which double election is indicated4 ,sulphate of lime and carbonate of ammonia in solution are brought together1 and there result a carbonate of lime and a sulphate of ammonia4 ,now1 in such cases nothing more than single elective attraction most probably occurs1 and the carbonic acid is seized by the lime1 by the great affinity of that earth for carbonic acid1 only after it has been set free from the ammonia1 and then1 by the force of cohesion acting with the combining powers1 the insoluble salt is precipitated4#bjd ,there is a curious fact in connection with this decomposition4 ,if carbonate of lime and sulphate of ammonia are mixed together dry1 and exposed1 in a closed vessel1 to a red heat1 sulphate of lime and carbonate of ammonia are formed4 ,these opposite effects are not very easily explained4 ,the action of heat is to set free the carbonic acid2 and it can only be by supposing that considerable differences of temperature reverse the laws of affinity1 that we can at all understand this phenomenon4 ,that different effects result at high temperatures from those which prevail at low ones1 recent experiments prove to us1 particularly those of ,boutigny1 already quoted when considering decomposition by calorific action4 ,under the term chemical affinity1 which we regard as a power acting at insensible distances1 and producing a change in bodies1 we are content to allow ourselves to believe that we have explained the great operations of nature4 ,we find that the vegetable and animal kingdoms are composed of carbon1 hydrogen1 oxygen1 and nitrogen4 ,the granite mountains of the earth1 and its limestone hills1 and all its other geological formations1 are found to be metals and oxygen1 and carbon and sulphur1 disposed to settle in harmonious union in their proper places by chemical affinity4 ,but what really is the power which combines atom to atom1 and unites molecule to molecule8 ,can we refer the process to heat8 ,the influence of caloric1 although by changing the form of bodies it sometimes assists combination1 is to be regarded rather as in antagonism to the power of cohesion4 ,can it be thought that electricity is active in producing the result8 ,during every change of state1 those phenomena which we term electrical are manifested2 but we thereby only prove the general diffusion of the electric principle1 and by no means show that electricity is the cause of the chemical change4 ,can light determine these changes8 ,it is evident1 although light may be a disturbing power1 that it cannot be the effective one2 for many of these decompositions and recompositions are constantly going on within the dark and silent depths of the earth1 to which a sunbeam cannot reach4 ,that the excitation on the surface of the earth1 produced by solar influence1 may modify those changes1 is probable4 ,it is1 however1 certain that we must regard all manifestations of chemical force as dependent upon some secret principles common to all matter1 diffused throughout the universe1 but modified by the influences of the known imponderable elements1 and by the mechanical force of aggregative attraction4 ,bodies undergo remarkable changes of form1 and present very different characters1 by reactions1 which are of several kinds4 ,we suppose that a permanent corpuscular arrangement is maintained so long as the equilibrium of the molecular forces is undisturbed4 ,water1 for instance1 remains unchanged so long as the balance of affinity is kept up between the oxygen and hydrogen of which it is composed1 or so long as the oscillations of force between these combining elements are equal2 but disturb this force1 or set up a new vibratory action1 as by passing an electric current through the water1 or by presenting another body1 which has the power of reacting upon one of these corpuscular systems1 and the water is decomposed1 the hydrogen and oxygen gases being set free1 or one alone is liberated1 and the other combined with the molecules of the agent employed1 and a new compound produced4 ,this is chemistry1 by which science we discover all the combinations of matter4 ,having reason to conclude that atom combines with atom1 according to a system most harmoniously arranged1 there can be no difficulty in conceiving that molecule unites with molecule1 in a manner regulated by some equally well-marked law4 ,it was1 indeed1 a discovery by ,wenzel1 of ,fribourg1 that1 in salts which decompose each other1 the acid which saturates one base will also saturate the other base2 and the subsequent observations of ,richter1 of ,berlin1 who attached proportional numbers to the acids and bases1 and who remarked that the neutrality of metallic salts does not change during the precipitation of metals by each other1 which led the way to the atomic theory of ,dr4 ,dalton1 to whom entirely belongs the observation1 that the equivalent of a compound body is the sum of the equivalents of its constituents1 and the discovery of combination in multiple proportions4 ,the elements of a molecule can take a new arrangement amongst themselves1 without any alteration in the number of the atoms or of their weight1 and thus give rise to a body of a different form and colour1 although possessing the same chemical constitution4 ,this is the case with many of the organic compounds of carbon and hydrogen4 ,the elements of a compound may be disassociated1 and thus the dissimilar substances of which it is composed set free4 ,a piece of chalk exposed to heat is1 by the disturbance of its molecular arrangement1 changed in its nature2 a gaseous body1 carbonic acid1 is liberated1 and quick-lime 7oxide of calcium7 is left behind4 ,if this carbonic acid is passed through red-hot metal tubes1 or brought in contact with heated potassium1 it is resolved into oxygen and charcoal--the oxygen combining with the metal employed4 ,the oxide of calcium 7lime71 if subjected to the action of a powerful galvanic current1 is converted into oxygen and a metal1 calcium4 ,thus we learn that chalk is a body consisting of two compound molecules1--carbonic acid1 which is formed by the combination of an atom of carbon with two atoms of oxygen1--and lime1 which results from the union of an atom of calcium with one of oxygen4 ,the condition requisite to the production of chemical action between bodies is that they should be dissimilar4 ,two elementary atoms are placed within the spheres of each other's influences1 and a compound molecule results4 ,oxygen and hydrogen form water2 oxygen and carbon give rise to carbonic acid2 nitrogen and hydrogen unite to form ammonia2 and chlorine and hydrogen to produce hydrochloric acid4 ,in all these cases an external force is required to bring the atoms within the range of mutual affinity3 flame1--the electrical spark1--actinism1--or the interposition of a third body1 is necessary in each case4 ,there are other examples in which no such influence is required4 ,potassium and oxygen instantly unite3 chlorine1 iodine1 and bromine immediately1 and with much violence1 combine with the metals to form chlorides1 iodides1 or bromides4 ,with compound molecules the action is in many cases equally active1 and combination is readily effected1 as in the cases of the acids and the oxides of some metals1 which are all instances of the most common chemical attraction4 ,an elementary or simple molecule and molecules of a compound and different constitution are brought together1 and a new compound results from an interchange of their atoms1 whilst an element is liberated4 ,these are essentially illustrations of analytical chemistry4 ,sulphuretted hydrogen is mixed with chlorine2 the chlorine combines with the hydrogen1 and sulphur is set free4 ,potassium is put into water1 and it combines with the oxygen of the water1 whilst the hydrogen is liberated4 ,two compound molecules being brought together may decompose each other1 and form two new compounds by an interchange of their elements4 ,one element may be substituted for another under certain circumstances4 ,gold may be replaced by mercury2 copper will take the place of silver2 and iron will occasion the separation of copper from its solutions1 the iron itself being dissolved to supply its place2 chlorine will substitute hydrogen in the carburetted hydrogen gases2 and many other examples might be adduced4 ,chemical phenomena very frequently become of a complex character2 and one1 two1 or three of these cases may be occurring at the same time in the decomposition of one compound by another4 ,such are the general features of chemical science4 ,many peculiarities and remarkable phenomena connected with chemical investigations will be named1 as the examination of the elementary composition of matter is proceeded with2 but1 although the philosophy of chemical action is of the highest interest1 it must not be allowed to detain us with its details1 which are1 indeed1 more in accordance with a treatise on the science than one which professes to do no more than sketch out those prevailing and striking features which1 whilst they elucidate the great truths of nature1 are capable of being employed as suggestive examples of the tendency of scientific investigation to enlarge the boundaries of thought1 and give a greater elevation to the mind1 leading us from the merely mechanical process of analysis up to the great synthetical operations1 by which all that is found upon the earth for its ornament1 or our necessities1 is created4 ,among the most remarkable phenomena within the range of physical chemistry are those of ,catalysis1 or1 as it has also been called1 the 8,action of presence40#bje ,there are a certain number of bodies known to possess the power of resolving compounds into new forms1 without undergoing any change themselves4 ,kirchoff discovered that the presence of an acid1 at a certain temperature1 converted starch into sugar and gum1 no combination with the acid taking place4 ,thenard found that manganese1 platinum1 gold1 and silver1 and1 indeed1 almost any solid organic body1 had the power of decomposing the binoxide of hydrogen by their presence merely1 no action being detected on these bodies4 ,edmund ,davy found that powdered platinum1 moistened with alcohol1 became red-hot1 fired the spirit1 and converted it into vinegar1 without undergoing1 itself1 any chemical change4 ,dbereiner next discovered that spongy platinum fired a current of hydrogen gas directed upon it1 which1 by combining with the oxygen of the air1 formed water4 ,dulong and ,thenard traced the same property1 differing only in degree1 through iridium1 osmium1 palladium1 gold1 silver1 and even glass4 ,further investigation has extended the number of instances2 and it has even been found that a polished plate of platinum has the power of condensing hydrogen and oxygen so forcibly upon its surface1 that these gases are drawn into combination and form water1 with a development of heat sufficient to ignite the metal4 ,this power1 whatever it may be1 is common in both organic and inorganic nature1 and on its important purposes ,berzelius has the following remarks3-- 8,this power gives rise to numerous applications in organic nature2 thus1 it is only around the eyes of the potato that diastase exists3 it is by means of catalytic power that diastase1 and that starch1 which are insoluble1 are converted into sugar and into gum1 which1 being soluble1 form the sap that rises in the germs of the potato4 ,this evident example of the action of catalytic power in an organic secretion1 is not1 probably1 the only one in the animal and vegetable kingdom1 and it may hereafter be discovered that it is by an action analogous to that of catalytic power1 that the secretion of such different bodies is produced1 all which are supplied by the same matter1 the sap in plants1 and the blood in animals40#bjf ,it is1 without doubt1 to this peculiar agency that we must attribute the abnormal actions produced in the blood of living animals by the addition of any gaseous miasma or putrid matter1 of which we have1 in all probability1 a fearful example in the progress of ,asiatic cholera2 therefore the study of its phenomena becomes an important part of public hygine4 ,physical research has proved to us that all bodies have peculiar powers1 by which they condense with varying degrees of force gases and vapours upon their surfaces2 every body in nature may1 indeed1 be regarded as forming its own peculiar atmosphere4 ,to this power1 in all probability1 does catalysis belong4 ,different views have1 however1 prevailed on this subject1 and ,dr4 ,lyon ,playfair#bjg argues that the catalytic force is merely a modified form of chemical affinity1 exerted under peculiar conditions4 ,whatever may be the power producing chemical change1 it acts in conformity with some fixed laws1 and in all its transmutations1 an obedience to a most harmonious system is apparent4 ,it is curious to observe the remarkable character of many of these natural transmutations of matter1 but we must content ourselves with a few examples only4 ,for instance3-- ,sugar1 oxalic acid1 and citric acid are very unlike each other1 yet they are composed of the same elements2 the first is used as a general condiment1 the second is a destructive poison1 and the third a grateful and healthful acid3 sugar is readily converted into oxalic acid1 and in the process of ripening fruits nature herself converts citric acid into sugar4 ,again1 starch1 sugar1 and gum would scarcely be regarded as alike1 yet their only difference is in the mode in which carbon1 hydrogen1 and oxygen combine4 ,they are composed of the same principles1 in the following proportions3-- ,carbon4 ,hydrogen4 ,oxygen4 ,starch #ab #aj #aj ,sugar #ab #aa #aa ,gum #ab #aa #aa ,these isomeric groups certainly indicate some law of affinity which science has not yet discovered4 ,similar and even more remarkable instances might be adduced of the same elements producing compounds very unlike each other2 but the above have been selected from their well-known characters4 ,indeed1 we may state with truth that all the varieties of the vegetable world--their woody fibre--their acid or alkaline juices--the various exudations of plants--their flowers1 fruit1 and seeds1 and the numerous products which1 by art1 they are made to yield for the uses of man1 are1 all of them1 compounds of these three elements1 differing only in the proportions in which they are combined with nitrogen1 or in some peculiar change of state in one or other of the elementary principles4 ,the chemist is now enabled by simple processes1 from the refuse of manufactories to produce fruit essences which are equal in flavour to the natural production2 and from benzoic acid1 which is obtained in great abundance from the houses in which cows are kept1 the most delicate essences are produced1 which are given to the world as the distillations of a thousand flowers4 ,by the impulse given to organic chemistry by ,liebig1 our knowledge of the almost infinite variety of substances1 in physical character exceedingly dissimilar1 which result from the combination of oxygen1 hydrogen1 and carbon1 in varying proportions1 has been largely increased4 ,and the science is now in that state which almost causes a regret that any new organic compounds should be discovered1 until some industrious mind has undertaken the task of reducing to a good general classification the immense mass of valuable matter which has been accumulated1 but which1 for all practical purposes1 remains nearly useless and unintelligible4 ,these combinations1 almost infinitely varied as they are1 and so readily produced and multiplied as to be nearly at the will of the organic analyst1 are not1 any of them1 accidental3 they are the result of certain laws1 and atom has united with atom in direct obedience to principles which have been through all time in active operation4 ,they are unknown2 the researches of science have not yet developed them1 and the philosopher has not yet made his deductions4 ,they are to be referred to some secret fixed principles of action1 to a force which has impressed upon every atom of the universe its distinguishing character4 ,chemistry makes us familiar with a system of order4 ,the researches of analysts have proved that every body has a particular law of combination1 to which it is bound by a mathematical precision2 but it is not proportional combination alone we have to consider4 ,if allotrophy is evidenced in the mineral world1 it is certainly far more strikingly manifested in the vegetable and animal kingdoms4 ,there are some cases in which bodies appear to combine without any limitation1 as spirit of wine and water1 sulphuric acid and water2 but these must be considered as conditions of mixture rather than of chemical combination4 ,the composition of bodies is fixed and invariable1 and a compound substance1 so long as it retains its characteristic properties1 must consist of the same elements united in the same proportions4 ,thus1 sulphuric acid is invariably composed of #af parts of sulphur and #bd parts of oxygen4 ,chalk1 whether formed by nature or by the chemist1 yields #dcga parts of carbonic acid1 and #efbi parts of lime4 ,the rust which forms upon the surface of iron by the action of the atmosphere1 is as invariable in its composition as if it had been formed by the most delicate adjustment of weight by the most accurate manipulator1 being #bh parts of iron and #ab parts of oxygen4 ,this law is the basis of all chemical inquiry1 all analytical investigations depending upon the knowledge it affords us1 that we can only produce certain undeviating compounds as the results of our decompositions4 ,we are not in a position to offer any explanation which will account for these constant quantities in combination4 ,the forces of cohesion and elasticity have been advanced in explanation1 on the strength of the fact that the solubility of a salt in water is regulated by cohesion1 and that of a gas by its elasticity4 ,although it may appear that some cases of chemical combination are due to these powers1--as1 for instance1 when the union of oxalic acid or sulphuric acid with lime produces an insoluble salt1--we cannot thus explain the constant proportions in which the metals1 sulphur1 oxygen1 and similar bodies1 unite4 ,it is quite certain there is a power or principle1 which we have not yet reached1 upon which are dependent all the phenomena which we now embrace under the term chemical affinity4 ,another law teaches us that when compound bodies combine in more than one proportion1 every additional union represents a multiple of the combining proportion of the first4 ,with the difficulty which arises from the sub-multiple compounds we cannot deal3--further research may render their laws less obscure4 ,we have seen that #h parts of oxygen unite with #a of hydrogen and #ad of nitrogen4 ,it also unites with #aaj of silver1 #if of platinum1 #dj of potassium1 #cf of chlorine1 and #bjj parts of mercury1 giving rise to-- ,water #i ,nitrous oxide #bb ,oxide of silver #aah ,oxide of platinum #ajd ,potash #dh ,oxide of chlorine #dd ,oxide of mercury #bjh ,in these proportions1 or in multiples of them1 and in no others1 will these bodies unite with the acids or other compounds4 ,it will1 of course1 be understood that any other numbers may be adopted1 provided they stand in the same relation to each other4#bjh ,from the discovery of these harmonious arrangements was deduced the beautiful atomic theory to which allusion has been already made4 ,indeed1 there does not appear to be any other way of explaining these phenomena than by the hypothesis that the ultimate atoms of bodies have relatively the weights which we arbitrarily assign to them1 as their combining quantities4 ,these views are further confirmed by the fact1 that gaseous bodies unite together by volume in very simple definite proportions3--#ajj measures of hydrogen and #bjj measures of oxygen form water2 #ajj measures of oxygen and #ajj measures of vapour of sulphur form sulphurous acid gas4 ,ammoniacal gas consists of #cjj volumes of hydrogen and #ajj volumes of nitrogen1 condensed by combination into #bjj volumes2 consequently1 we are enabled most readily to calculate the specific gravity of ammoniacal gas4 ,the specific gravity of nitrogen is #jigbb1 that of hydrogen #jjfid4 ,now1 three volumes of hydrogen are equal to #jbjhb3 this added to #jigbb is equal to #aahjd1 which is exactly the specific gravity obtained by experiment4 ,there is no doubt1 from the generality with which this law of volumes prevails1 that it would be found to extend through all substances1 provided they could be rendered gaseous2 in other words1 there is abundant proof to convince us that throughout nature the process of combination1 in the most simple ratio of volumes1 is in operation to produce all the forms of matter known to us4 ,it has been shown1 by the investigations of ,dr4 ,dalton1 in #ahdj1 that salts1 containing water of crystallization1 dissolve in water without increasing the bulk of the fluid more than is due to the liquefaction of the water which these salts contain2 while ,joule and ,playfair have shown that the anhydrous salts take up no space in solution4 ,from this we are naturally led to conclude that the volume occupied by a salt in the solid state has a certain relation to the volume of the same salt when in solution1 and has also a fixed relation to the volume occupied by any other salt4 ,the law appears to be3--the atomic volume of any salt whatever 7anhydrous or hydrated7 is a multiple of #aa1 or of a number near #aa1 or a multiple of #ih 7the atomic volume of ice71 or the sum of a multiple of #aa or #ih4 ,marignac1 who has also paid much attention to the subject1 does not think these numbers absolutely correct1 but approximately so4#bji ,it would be a beautiful exemplification of the simplicity of ,nature's operations1 if it should be clearly proved that the atomic volume of solid water 7ice7 regulated the combining proportions by volume of all other bodies1--that it was the standard by which chemical combination and ordinary solution were determined4 ,in addition to the laws already indicated1 there appear to be some others of which1 as yet1 we have a less satisfactory knowledge1 and1 as a remarkable case1 we may adduce the phenomena of substitution1 or that power which an elementary body1 under certain conditions1 possesses1 of turning out one of the elements of a compound1 and of taking its place4#baj ,thus1 the hydrogen of a compound radical1 as carburetted hydrogen1 may be replaced by chlorine1 equivalent for equivalent1 and form a chloride of carbon1 which being constructed on the same type as the original1 will have the same general laws of combination4 ,under the influence of these laws1 all the combinations which we discover in nature take place4 ,the metals1 and oxygen1 and sulphur1 and phosphorus unite4 ,the elements of the organic type1 entering into the closest relations1 give rise to every form of vegetable life4 ,the acids1 the gums1 the resins1 and the sugar which plants produce2 and those yet more complicated animal substances1 bone1 muscle1 blood1 and bile2 albumen1 casein1 milk1 with those compounds which1 under the influence of vital power1 resolve themselves into substances which are essential to the existence1 health1 and beauty of the animal fabric1 are all dependent on these laws4 ,but these metamorphoses must be further considered in our examination of the more striking cases of chemical action4 ,the changes which result from organic combination are so remarkable1 and withal they show how completely the whole of the material world is in subjection to chemical force1 and every variety of form the result of mysterious combination1 that some particular reference to these metamorphoses is demanded4 ,in nearly all cases of decided chemical action1 all trace of the characters of the combining bodies disappear4 ,we say decided chemical action1 because1 although sulphuric acid and water combine1 and salts dissolve in water1 we may always recognize their presence1 and therefore these and similar cases cannot be regarded as strict examples of the phenomena under consideration4 ,hydrogen and oxygen1 in combining1 lose their gaseous forms1 and are condensed into a liquid--water4 ,sulphuric acid is intensely sour and corrosive2 potash is highly caustic2 but united they form a salt which is neither3 they appear to have destroyed the distinguishing characters of each other4 ,combined bodies frequently occupy less space than they did previously to combination1 of which numerous particular instances might be adduced4 ,gases in many cases undergo a remarkable condensation when chemically combined4 ,in slaking lime1 the water becomes solid in the molecules of the hydrate of lime formed1 and the intense heat produced arises from the liberation of that caloric which had been employed to keep the water liquid4 ,when a solid passes into the liquid state1 cold is produced by the abstraction from surrounding objects of the heat required to effect fluidity4 ,an alteration of temperature occurs whenever chemical change takes place1 as we have already shown1 with a few trivial and uncertain exceptions4 ,the disturbance caused by the exercise of the force of affinity frequently leads to the development of several physical powers4 ,changes of colour commonly arise2 indeed1 there does not appear to be any relation between the colour of a compound and that of its elements4 ,iodine is of a deep iron-grey colour2 its vapour is violet2 yet it forms beautifully white salts with the alkalies1 a splendid red salt with mercury1 and a yellow one with lead4 ,the salts of iron vary from white and yellow to green and dark brown4 ,those of copper1 a red metal1 are of a beautiful blue and green colour1 and the anhydrous sulphate is white4 ,isomorphism1 which appears in a very remarkable manner among the organic compounds1 has1 under the head of crystallization1 already had our attention4 ,there is also a class of bodies which are said to be isomeric2 that is1 to have the same composition1 although different in their physical characters4 ,but the idea that bodies exist1 which1 although of a decidedly different external character1 are of exactly the same chemical composition and physical condition1 is not tenable2 and in nearly all the examples which have been carefully examined1 a difference in the aggregate number of atoms1 or in the mode in which those atoms have respectively arranged themselves1 or that peculiar physical difference designated by the term allotropy1 has been detected4 ,oil of turpentine and oil of lemons have the same composition1 each being composed of five equivalents of carbon and four of hydrogen4 ,these substances form1 from the striking difference perceptible in their external characters1 a good example of isomerism4 ,the laws of organic chemistry are not1 however1 the same as those applying to inorganic combinations4 ,organic chemistry is well defined by ,liebig1 as the chemistry of compound radicals2 and under the influence of vitality1 nature produces compounds which have all the properties of simple elements4#baa ,when we reflect upon the conditions which prevail throughout nature1 with a few of which only has science made us acquainted1 we cannot fail to be struck with the various phases of being which are presented to our observation1 and the harmonious system upon which they all appear to depend4 ,when we discover that bodies are formed of certain determinate atoms1 which unite one with another1 according to an arithmetical system1 to form molecules1 which1 combining with molecules1 observe a similar law1 we see at once that all the harmonies of chemical combination--the definite proportions1 laws of volume1 and the like--are but the necessary consequences of these simple and guiding first principles4 ,in the pursuit of truth1 investigators must discover still further arrangements1 which1 from their perfection1 may be compared to the melodious interblending of sweet sounds1 and many of the apparently indeterminate combinations will1 beyond a doubt1 be shown to be as definite as any others4 ,but we cannot reflect upon the fact that these atoms and these molecules are guided in their combinations by impulses1 which we can only explain by reference to human passions1 as the term elective affinity implies1 without feeling that an impenetrable mystery of a grand and startling character in its manifestations surrounds each grain of dust which is hurried along upon the wind4 ,we now1 habitually1 speak of attraction and repulsion--of the affinity and non-affinity of bodies4 ,we are disposed1 from the discovery of the attractive and repelling poles of electrified substances1 to regard these powers in all cases as depending upon some electrical state1 and we write learnedly upon the laws of these forces4 ,after all1 it would be more honest to admit1 that we know no more of the secret impulses which regulate the combinations of matter1 than did those who satisfied themselves by referring all phenomena of these kinds to sympathies and antipathies3 terms which have a poetic meaning1 conveying to the mind1 with considerable distinctness1 the fact1 and giving the idea of a feeling--a passion--involving and directing inanimate matter1 similar to that which stirs the human heart1 and certainly calculated to convey the impression that there is working within all things a living principle1 and pointing1 indeed1 to 8the soul of the world40 ,the animated marble of ancient story is far less wonderful than the fact1 proved by investigation1 that every atom of matter is penetrated by a principle which directs its movements and orders its positions1 and involved by an influence which extends1 without limits1 to all other atoms1 and which determines their union1 or otherwise4 ,we have gravitation1 drawing all matter to a common centre1 and acting from all bodies throughout the wide regions of unmeasured space upon all4 ,we have cohesion1 holding the particles of matter enchained1 operating only at distances too minute for the mathematician to measure2 and we have chemical attraction1 different from either of these1 working no less mysteriously within absolutely insensible distances1 and1 by the exercise of its occult power1 giving determinate and fixed forms to every kind of material creation4 ,the spiritual beings1 which the poet of untutored nature gave to the forest1 to the valley1 and to the mountain1 to the lake1 to the river1 and to the ocean1 working within their secret offices1 and moulding for man the beautiful or the sublime1 are but the weak creations of a finite mind1 although they have for us a charm which all men unconsciously obey1 even when they refuse to confess it4 ,they are like the result of the labours of the statuary1 who1 in his high dreams of love and sublimated beauty1 creates from the marble block a figure of the most exquisite moulding which mimics life4 ,it charms us for a season2 we gaze and gaze again1 and its first charms vanish2 it is ever and ever still the same dead heap of chiselled stone4 ,it has not the power of presenting to our wearying eyes the change which life alone enables matter to give2 and we admit the excellence of the artist1 but we cease to feel at his work4 ,the creations of poetry are pleasing1 but they never affect the mind in the way in which the poetic realities of nature do4 ,the sylph moistening a lily is a sweet dream2 but the thoughts which rise when first we learn that its broad and beautiful dark-green leaves1 and its pure and delicate flower1 are the results of the alchemy which changes gross particles of matter into symmetric forms1--of a power which is unceasingly at work under the guidance of light1 heat1 and electrical force1--are1 after our incredulity has passed away--for it is too wonderful for the untutored to believe at once--of an exalting character4 ,the flower has grown under the impulse of principles which have traversed to it on the solar beam1 and mingled with its substance4 ,a stone is merely a stone to most men4 ,but within the interstices of the stone1 and involving it like an atmosphere1 are great and mighty influences1 powers which are fearful in their grander operations1 and wonderful in their gentler developments4 ,the stone and the flower hold1 locked up in their recesses1 the three great known forces--light1 heat1 and electricity3 and1 in all probability1 others of a more exalted nature still1 to which these powers are but subordinate agents4 ,such are the facts of science1 which1 indeed1 are the true 8sermons in stones10 and the most musical of 8tongues in trees40 ,how weak are the creations of romance1 when viewed beside the discoveries of science6 ,one affords matter for meditation1 and gives rise to thoughts of a most ennobling character2 the other excites for a moment1 and leaves the mind vacant or diseased4 ,the former1 like the atmosphere1 furnishes a constant supply of the most healthful matter2 the latter gives an unnatural stimulus1 which compels a renewal of the same kind of excitement1 to maintain the continuation of its pleasurable sensations4 ,,footnotes3 #bjj ,all the phenomena connected with volcanic action1 and the theories connected therewith1 will be found in ,dr4 ,daubeny's work1 ,a description of active and extinct ,volcanoes1 of ,earthquakes1 and of ,thermal ,springs4 #ahdh4 #bja ,graham's ,elements of ,chemistry4 ,new ,edition4 #bjb ,graham's ,elements of ,chemistry2 and ,brande's ,manual4 #bjc ,of these tables of attraction the following may be taken as a specimen3-- ,,sulphuric ,,acid4 ,baryta4 ,strontia4 ,potassa4 ,soda4 ,lime4 ,magnesia4 ,ammonia4 ,it thus appears that baryta separates sulphuric acid from its compounds with all inferior substances1 and that ammonia is separated from the acid by all that are above it4 #bjd ,berthollet3 ,essai de ,statique ,chimique1 #ahjc4 ,sir ,humphry ,davy1 in his ,elements of ,chemical ,philosophy1 has given an excellent review of the views of ,berthollet4 #bje ,on certain combinations of a new acid1 formed of ,azote1 ,sulphur1 and ,oxygen2 by ,j4 ,pelouze4 ,translated from ,annales de ,chimie1 vol4 xvi41 for ,scientific ,memoirs1 vol4 i4 p4 #dgj4 ,some ideas of a new force acting in the combinations of ,organic ,compounds1 by ,berzelius3 ,annales de ,chimie1 vol4 lxi4 ,the conclusion come to by this eminent chemist is expressed in the following translation3--8,this new power1 hitherto unknown1 is common both in organic and inorganic nature4 ,i do not believe that it is a power which is entirely independent of the electro-chemical affinities of the substance4 ,i believe1 on the contrary1 that it is merely a new form of it2 but so long as we do not see their connection and mutual dependence1 it will be more convenient to describe it by a separate name4 ,i shall1 therefore1 call it catalytic power3 ,i shall also call catalysis1 the decomposition of bodies by this force--in the same way as the decomposition of bodies by chemical affinity is termed analysis40 #bjf ,berzelius3 ,annales de ,chimie1 vol4 lxi4 #bjg ,on ,transformations produced by ,catalytic ,bodies3 by ,lyon ,playfair1 ,esq42 ,phil4 ,mag41 vol4 xxxi4 p4 #aia1 #ahdg4--8;,facts have been brought forward to show that there is at least as much probability in the view that the catalytic force is merely a modified form of chemical affinity exerted under peculiar conditions1 as there is in ascribing it to an unknown power1 or to the communication of an intestine motion to the atoms of a complex molecule4 ,numerous cases have been cited1 in which the action results when the assisting or catalytic body is not in a state of change2 and attempts have been made to prove1 by new experiments1 that the catalytic power exercises its peculiar power by acting in the same direction as the body decomposing1 or entering into union1 but under conditions in which its own affinity cannot always be gratified40 #bjh ,consult ,graham's ,chemistry1 ,on ,combining ,proportions4 #bji ,memoir on ,atomic ,volume and ,specific ,gravity4 ,messrs4 ,lyon ,playfair and ,joule4--,philosophical ,magazine1 vol4 xxvii4 p4 #dec1 or ,transactions of ,chemical ,society of ,london4 ,observations on the above1 by ,professor de ,marignac4--,bibliothque ,universelle1 ,feb4 #ahdf4 ,on the ,relation of the ,volumes of bodies in the solid state1 to their equivalents1 or atomic weights3 by ,professor ,otto4 ,studies on the connection between the atomic weights1 crystalline form1 and density of bodies3 by ,m4 ,filhol4 ,translated for the ,cavendish ,society1 and published in their ,chemical ,reports and ,memoirs4 #baj ,comptes ,rendus de l',acadmie des ,sciences1 #ahdj1 ,no4 #e4 ,a good translation of ,dumas's ,memoir appeared in the ,philosophical ,magazine1 from which ,i extract the following familiar exposition of the laws of substitution3--8,let me make a comparison drawn from a familiar order of ideas4 ,let us put ourselves in the place of a man overlooking a game at chess without the slightest knowledge of the game4 ,he would soon remark that the pieces must be used according to positive rules4 ,in chemistry1 the equivalents are our pieces1 and the law of substitutions one of the rules which preside over their moves4 ,and as in the oblique move of the pawns one pawn must be substituted for another1 so in the phenomena of substitution one element must take the place of another4 ,but this does not hinder the pawn from advancing without taking anything1 as the law of substitution does not hinder an element from acting on a body without displacing or taking the place of any other element that it may contain40--,memoir on the ,law of ,substitutions1 and ,theory of ,chemical ,types4 #baa ,liebig's ,chemistry in its application to ,agriculture and ,physiology3 translated by ,lyon ,playfair1 ,ph4 ,d4 ,animal ,chemistry1 or ,chemistry in its application to ,physiology and ,pathology3 by ,justus ,liebig2 translated by ,wm4 ,gregory4 ,,chapter ,,xii4 ,,chemical ,,phenomena4 ,water--,its ,constituents--,oxygen--,hydrogen--,pero xide of ,hydrogen--,physical ,property of ,water--,ice--,sea ,water--,chlorine--,muriatic ,acid--,iodine--,bromine--,compounds of ,hydrogen with ,carbon--,combustion--,flame--,safety ,lamp--,respiration--,animal ,heat--,the ,atmosphere--,carbonic ,acid--,influence of ,plants on the ,air--,chemical ,phenomena of ,vegetation--,compounds of ,nitrogen--,mineral ,kingdom1 c4 c4 ,without attempting anything which shall approach even to the character of a sketch of chemical science1 we may be allowed1 in our search after exalting truths1 to select such examples of the results of combination as may serve to elucidate any of the facts connected with natural phenomena4 ,in doing this1 by associating our examination with well-known natural objects or conditions1 the interpretation afforded by analysis will be more evident1 and the operation of the creative forces rendered more striking and familiar1 particularly if at the same time we examine such physical conditions as are allied in action1 and are sufficiently explanatory of important features4 ,a large portion of this planet is covered by the waters of the ocean1 of lakes and rivers4 ,water forms the best means of communication between remote parts of the earth4 ,it is in every respect of the utmost importance to the animal and vegetable kingdom2 and1 indeed1 it is indispensable in all the great phenomena of the inorganic world4 ,the peculiarities of saltness or freshness in water are dependent upon its solvent powers4 ,the waters of the ocean are saline from holding dissolved various saline compounds1 which are received in part from1 and imparted also to1 the marine plants4 ,perfectly pure water is without taste3 even the pleasant character of freshly-drawn spring-water is due to the admixture of atmospheric air and carbonic acid4 ,the manner in which water absorbs air is evidently due to a peculiar physical attractive force1 the value of which we do not at present clearly perceive or correctly estimate4 ,it is chemically composed of two volumes of hydrogen gas--the lightest body known1 and at the same time a highly inflammable one--united with one volume of oxygen1 which excites combustion1 and continues that action1--producing heat and light1--with great energy4 ,by weight1 one part of hydrogen is united with eight of oxygen1 or in #ajj parts of water we find #hhi oxygen1 and #aaa of hydrogen gas4 ,that two such bodies should unite to furnish the most refreshing beverage1 and indeed the only natural drink for man and animals1 is one of the extraordinary facts of science4 ,hydrogen will not support life--we cannot breathe it and live2 and oxygen would over-stimulate the organic system1 and1 producing a kind of combustion1 give rise to fever in the animal frame2 but1 united1 they form that drink1 for a drop of which the fevered monarch would yield his diadem1 and the deprivation of which is one of the most horrid calamities that can be inflicted upon any living thing4 ,water appears as the antagonist principle to fire1 and the ravages of the latter are quenched by the assuaging powers of the former2 yet a mixture of oxygen and hydrogen gases1 in the exact proportion in which they form water1 explodes with the utmost violence on the contact of flame1 and1 when judiciously arranged1 produces the most intense degree of heat known2--such is the remarkable difference between a merely mechanical mixture and a chemical combination4 ,beyond this1 we have already noticed the remarkable fact that water deprived of air is explosive at a comparatively low temperature1 less than #cjj2 gunpowder requiring a temperature of nearly #ajjj ,f4 ,if we place in a globe1 oxygen and hydrogen gases1 in the exact proportions in which they combine to form water1 they remain without change of state4 ,they appear to mix intimately2 and1 notwithstanding the difference in the specific gravities of the two gases1 the lighter one is diffused through the heavier in a curious manner1 agreeably to a law which has an important bearing on the conditions of atmospheric phenomena4#bab ,the moment1 however1 that an incandescent body1 or the spark from an electric machine1 is brought into contact with the mixed gases1 they ignite1 explode violently1 and combine to form water4 ,the discovery of the composition of water was thus synthetically made by ,cavendish--its constitution having been previously theoretically announced by ,watt4#bac ,if1 instead of combining oxygen and hydrogen in the proportions in which they form water1 we compel the hydrogen to combine with an additional equivalent of oxygen1 we have a compound possessing many properties strikingly different from water4 ,this--peroxide of hydrogen1 as it is called--is a colourless liquid1 less volatile than water1 having a metallic taste4 ,it is decomposed at a low temperature1 and1 at the boiling point1 the oxygen escapes from it with such violence1 that something like an explosion ensues4 ,all metals1 except iron1 tin1 antimony1 and tellurium1 have a tendency to decompose this compound1 and separate it into oxygen and water4 ,some metals are oxidized during the decomposition1 but gold1 silver1 platinum1 and a few others1 still retain their metallic state4 ,if either silver1 lead1 mercury1 gold1 platinum1 manganese1 or cobalt1 in their highest states of oxidation1 are put into a tube1 containing this peroxide of hydrogen1 its oxygen is liberated with the rapidity of an explosion1 and so much heat is excited that the tube becomes red hot4 ,these phenomena1 to which we have already referred in noticing catalysis1 are by no means satisfactorily explained1 and the peculiar bleaching property possessed by the peroxide of hydrogen sufficiently distinguishes it from water4 ,there are few combinations which show more strikingly than this the difference arising from the chemical union of an additional atom of one element4 ,similar instances are numerous in the range of chemical science2 but scarcely any two exhibit such dissimilar properties4 ,during the ordinary processes of combustion1 it has been long known that water is formed by the combination of the hydrogen of the burning body with the oxygen of the air4 ,the recent researches of ,schnbein have shown that a peculiar body1 which has been regarded as a peroxide of hydrogen1 to which he has given the name of ,,ozone1 is produced at the same time1 and that it is developed in a great many ways1 particularly during electrical changes of the atmosphere4 ,thus we obtain evidence that this remarkable compound1 which was considered as a chemical curiosity merely1 is diffused very generally through nature1 and produced under a great variety of circumstances4 ,during the excitation of an electrical machine1 or the passage of a galvanic current through water by the oxidation of phosphorus1 and probably in many similar processes--in particular those of combustion1 and we may therefore infer also of respiration--this body is formed4 ,from observations which have been made1 it would appear that1 during the night1 when the activity of plants is not excited by light1 they act upon the atmosphere in such a way as to produce this ozone2 and its presence is said to be indicated by its peculiar odour during the early hours of morning4 ,we are not yet acquainted with this body sufficiently to speculate on its uses in nature3 without doubt1 they are important1 perhaps second to those of water only4 ,it is probable1 as we have already had occasion to remark1 that ozone may be the active agent in removing from the atmosphere those organic poisons to which many forms of pestilence are traceable2 and it is a curious fact1 that a low electrical intensity1 and a consequent deficiency of atmospheric ozone1 marks the prevalence of cholera1 and an excess distinguishes the reign of influenza4#bad ,some interesting researches appear to show the probability that ozone is simply oxygen in a state of high activity4 ,it has been found1 indeed1 that perfectly dry oxygen1 which will not bleach vegetable colours in the dark1 acquires1 by exposure to sunshine1 the power of destroying them4 ,becquerel has proved that this ozonous state may be produced in dry oxygen by passing a succession of electric sparks through it4 ,fremy passed the electric sparks on the outside of a tube which contained perfectly dry oxygen1 and it was found to have acquired the properties of ozone4 ,in this case1 and probably in the experiments of ,becquerel1 the light of the spark1 rather than the electricity1 appears to have been the active agent in producing this change4 ,schnbein himself does not appear disposed to regard ozone as being either peroxide of hydrogen1 or an allotropic oxygen4 ,he leans to his first view of its being an entirely new chemical element4 ,the energy of this ozone is so great1 that it has been found to destroy almost instantaneously the ,indian-rubber union joints of the apparatus in which it is formed4#bae ,water1 from the consideration of which a digression has been indulged in1 to consider the curious character of one of its elements1--water is one of the most powerful chemical agents1 having a most extensive range of affinities1 entering directly into the composition of a great many crystallizable bodies and organic compounds4 ,in those cases where it is not combined as water1 its elements often exist in the proportions in which water is formed4 ,gum1 starch1 and sugar1 only differ from each other in the proportions in which the elements of water are combined with the carbon4 ,in saline combinations1 and also in many organic forms1 we must regard the water as condensed to the solid form2 that is1 to exist as ice4 ,we well know that1 by the abstraction of heat1 this condition is produced2 but1 in chemical combinations1 this change must be the result of the mechanical force exerted by the power of the agency directing affinity4 ,in the case of water passing from a liquid to a solid state1 we have a most beautiful exemplification of the perfection of natural operations4 ,water conducts heat downwards but very slowly2 a mass of ice will remain undissolved but a few inches under water1 on the surface of which1 ether1 or any other inflammable body1 is burning4 ,if ice 7solid water7 swam beneath the surface1 the summer sun would scarcely have power to thaw it2 and thus our lakes and seas would be gradually converted into solid masses at our ordinary winter temperatures4 ,all similar bodies contract equally during the process of cooling1 from the highest to the lowest points to which the experiments have been carried4 ,it has been thought that if this applied to water1 the result would be the sudden consolidation of the whole mass4 ,a modification of the law has been supposed to take place to suit the peculiar circumstances of water4 ,nature never modifies a law for a particular purpose2 we must1 therefore1 seek to explain the action of the formation of ice1 as we know it1 by some more rational view4 ,water expands by heat1 and contracts by cold2 consequently1 the coldest portions of this body occupy the lower portions of the fluid2 but it must be remembered that these parts are warmed by the earth4 ,ross1 however1 states that at the depth of #a1jjj fathoms the sea has a constant temperature of #ci4 ,water is said to be at its point of greatest density at #dj of ,fahrenheit's thermometer2 in cooling further1 this fluid appears to expand1 in the same way as if heated3 and1 consequently1 water colder than this point1 instead of being heavier1 is lighter1 and floats on the surface of the warmer fluid4 ,it does not seem that any modification of the law is required to account for this phenomenon4 ,water cooled to #dj still retains its peculiar corpuscular arrangement2 but immediately it passes below that temperature1 it begins to dispose itself in such a manner that visible crystals may form the moment it reaches #cb4 ,now1 if we conceive the particles of water1 at #ci1 to arrange themselves in the manner necessary for the assumption of the solid form1 by the particular grouping of molecules in an angular instead of a spheroidal shape1 it will be clear1 from what we know of the arrangement of crystals of water--ice--that they must occupy a larger space than when the particles are disposed1 side by side1 in minute spheres4 ,even the escape of air from the water in which it is dissolved is sufficient to give an apparent lightness to the colder water4 ,this expansion still goes on increasing1 from the same cause1 during the formation of ice1 so that the specific gravity of a mass of frozen water is less than that of water at any temperature below #dj4 ,it must not be forgotten that ice always contains a large quantity of air1 by which it is rendered buoyant4 ,water1 at rest1 may be cooled many degrees below the freezing point without becoming solid4 ,this is easily effected in a thin glass flask2 but the moment it is agitated1 it becomes a firm mass4 ,here we have the indication of another cause aiding in producing crystals of ice on the surface of water1 under the influence of the disturbance produced by the wind1 which does not extend to any depth4 ,as oxygen and hydrogen gases enter largely into other chemical compounds besides water1 it is important to consider some of the forms of matter into the composition of which these elements enter4 ,to examine this thoroughly1 a complete essay on chemical philosophy would be necessary2 we must1 therefore1 be content with referring to a few of the more remarkable instances4 ,the waters of the ocean are salt3 this arises from their holding1 in solution chloride of sodium 7muriate of soda--common culinary salt7 and other saline bodies4 ,water being present1 this becomes muriate of soda1--that is1 a compound of muriatic acid and soda3 muriatic acid is hydrogen1 combined with a most remarkable gaseous body1 called1 from its yellow colour1 chlorine2 and soda1 oxygen in union with the metal sodium1--therefore1 when anhydrous1 culinary salt is truly a chloride of sodium4 ,chlorine in some respects resembles oxygen2 it attacks metallic bodies with great energy2 and1 in many cases1 produces the most vivid incandescence1 during the process of combination4 ,it is a powerful bleaching agent1 is destructive to animal life1 and rapidly changes all organic tissues4 ,there are two other bodies in many respects so similar to chlorine1 although one is at the ordinary temperatures solid1 and the other fluid1 and which are also discovered in sea-water1 or in the plants growing in it1 that it is difficult to consider them otherwise than as different forms of the same principle4 ,these are iodine and bromine1 and they both unite with hydrogen to form acids4 ,the part which chlorine performs in nature is a great and important one4 ,combined in muriate of soda1 we may trace it in large quantities through the three kingdoms of nature1 and the universal employment of salt as a condiment indicates the importance to the animal economy of the elements composing it4 ,iodine has been traced through the greater number of marine plants1 existing1 apparently as an essential element of their constitution2 in some land plants it has also been found1 particularly in the ,armeria maritima1 when this plant grows near the sea3#baf it has been detected in some mineral springs1 and in small quantities in the mineral kingdom#bag combined as iodide of silver1 and in the aluminous slate of ,latorp in ,sweden4#bah ,bromine is found in sea-water1 although in extremely minute quantities1 in a few saline springs1 and in combination with silver2 but we have no evidence to show that its uses are important in nature4 ,hydrogen1 again1 unites with carbon in various proportions1 producing the most dissimilar compounds4 ,the air evolved from stagnant water1 and the fire-damp of the coal mine1 are both carburetted hydrogen2 and the gas which we employ so advantageously for illumination1 is the same1 holding an additional quantity of carbon in suspension4 ,naphtha1 and a long list of organic bodies1 are composed of these two chemical elements4 ,these combinations lead us1 naturally1 to the consideration of the great chemical phenomena of combustion1 which involve1 indeed1 the influences of all the physical powers4 ,by the application of heat1 we produce an intense action in a body said to be combustible2 it burns1--a chemical action of the most energetic character is in progress1 the elements which constitute the combustible body are decomposed1 they unite with some other elementary principles1 and new compounds are formed4 ,a body burns--it is entirely dissipated1 or it leaves a very small quantity of ashes behind unconsumed1 but nothing is lost4 ,its volatile parts have entered into new arrangements1 the form of the body is changed1 but its constituents are still playing an important purpose in creation4 ,the ancient notion that fire was an empyreal element1 and the ,stahlian hypothesis of a phlogistic principle on which all the effects of combustion depended1#bai have both given way to the philosophy of the unfortunate ,lavoisier--which has1 indeed1 been modified in our own times--who showed that combustion is but the development of heat and light under the influence of chemical combination4 ,combustion was1 at one period1 thought to be always due to the combination of oxygen with the body burning1 but research has shown that vivid combustion may be produced where there is no oxygen4 ,the oxidizable metals burn most energetically in chlorine1 and some of them in the vapour of iodine and bromine1 and many other unions take place with manifestations of incandescence4 ,supporters of combustion were1 until lately1 regarded as bodies distinct from those undergoing combustion4 ,for example1 hydrogen was regarded as a combustible body1 and oxygen as a supporter of combustion4 ,such an arrangement is a most illogical one1 since we may burn oxygen in an atmosphere of hydrogen1 in the same manner as we burn hydrogen in one of oxygen2 and so1 in all the other cases1 the supporter of combustion may be burnt in an atmosphere formed of the1 so called1 combustible4 ,the ordinary phenomena of combustion are1 however1 due to the combination of oxygen with the body burning2 therefore every instance of oxidization may be regarded as a condition of combustion1 the difference being only one of degree4 ,common iron1 exposed to air and moisture1 rusts2 it combines with oxygen4 ,pure iron1 in a state of fine division1 unites with oxygen so eagerly1 that it becomes incandescent1 and in both cases oxide of iron is formed4 ,this last instance is certainly a case of combustion2 but in what does it differ from the first one1 except in the intensity of the action8 ,the cases of spontaneous combustion which are continually occurring are examples of an analogous character to the above4 ,oxygen is absorbed1 it enters more or less quickly1 according to atmospheric conditions1 into chemical combination2 heat is evolved1 and eventually1--the action continually increasing1--true combustion takes place4 ,in this way our cotton-ships1 storehouses of flax1 piles of oiled-cloth1 sawdust1 c41 frequently ignite2 and to such an influence is to be attributed the destruction of two of our ships of war1 a few years since1 in ,devonport naval arsenal4#bbj ,in the economic production of heat and light1 we have the combination of hydrogen and carbon with the oxygen of common air1 forming water and carbonic acid4 ,in our domestic fires we employ coal1 which is essentially a compound of carbon and hydrogen containing a little oxygen and some nitrogen1 with some earthy matters which must be regarded as impurities2 the taper1 whether of wax or tallow1 is made up of the same bodies1 differing only in their combining proportions1 and1 like coal gas1 these burn as carburetted hydrogen4 ,all these bodies are very inflammable1 having a tendency to combine energetically with oxygen at a certain elevation of temperature4 ,we are at a loss to know how heat can cause the combination of those bodies4 ,sir ,humphry ,davy has shown that hydrogen will not burn1 nor a mixture of it with oxygen explode1 unless directly influenced by a body heated so as to emit light4#bba ,may we not1 therefore1 conclude that the chemical action exhibited in a burning body is a development of some latent force1 with which we are unacquainted1 produced by the absorption of light2--that a repulsive action at first takes place1 by which the hydrogen and carbon are separated from each other2--and that in the nascent state they are seized by the oxygen1 and again compelled1 though in the new forms of water and carbonic acid1 to resume their chains of combining affinity8 ,every equivalent of carbon and of hydrogen in the burning body unites with two equivalents of oxygen1 in strict conformity with the laws of combination4 ,the flame of hydrogen1 if pure1 gives scarcely any light1 but combined with the solid particles of carbon1 it increases in brightness4 ,the most brilliant of the illuminating gases is the olefiant gas1 produced by the decomposition of alcohol1 and it is only hydrogen charged with carbon to the point of saturation4 ,flame is a cone of heated vapour1 becoming incandescent at the points of contact with the air2 a mere superficial film only being luminous4 ,it is evident that all the particles of the gas are in a state of very active repulsion over the surface1 since flame will not pass through wire gauze of moderate fineness4 ,upon this discovery is founded the inimitable safety-lamp of ,davy1 by means of which the explosive gases of a mine are harmlessly ignited within a cage of wire gauze4 ,this effect has been attributed to a cooling influence of the metal2 but1 since the wires may be brought to a degree of heat but little below redness without igniting the fire-damp1 this does not appear to be the cause4 ,the conditions of the safety lamp may be regarded as presenting examples exactly the converse of those already stated with reference to the spheroidal state of water2 and it affords additional evidence that the condition of bodies at high temperatures is subject to important physical changes4 ,the principle upon which the safety lamp is constructed is1 that a mixture of the fire-damp and atmospheric air in certain proportions explodes upon coming in contact with a flame4 ,this mixture passes readily through a wire gauze1 under all circumstances1 and it1 of course1 thus approaches the flame of the lamp enclosed within such a material1 and it explodes4 ,but1 notwithstanding the mechanical force with which the exploding gas is thrown back against the bars of its cage1 it cannot pass them4 ,consequently1 the element of destruction is caught and caged2 and notwithstanding its fierceness and energy1 it cannot impart to the explosive atmosphere without1 any of its force4 ,no combustion can be communicated through the wire gauze4 ,the researches which led to the safety-lamp may be regarded as among the most complete examples of correct inductive experiment in the range of ,english science1 and the result is certainly one of the proudest achievements of physico-chemical research4 ,by merely enveloping the flame of a lamp with a metallic gauze1 the labourer in the recesses of the gloomy mine may feel himself secure from that outpouring current of inflammable gas1 which has been so often the minister of death2 he may walk unharmed through the explosive atmosphere1 and examine the intensity of its power1 as it is wasted in trifling efforts within the little cage he carries4 ,accidents have been attributed to the 8,davy10 as the lamp is called among the colliers2 but they may in most cases be traced to carelessness on the part of those whose duty it has been to examine the lamps1 or to the recklessness of the miners themselves4 ,that curious metal1 platinum1 and also palladium1 possesses a property of maintaining a slow combustion1 which the discoverer of the safety-lamp proposed to render available to a very important purpose4 ,if we take a coil of platinum wire1 and1 having made it red-hot1 plunge it into an explosive atmosphere of carburetted hydrogen and common air1 it continues to glow with considerable brightness1 producing1 by this very peculiar influence1 a combination of the gases1 which is discovered by the escape of pungent acid vapours4 ,over the little flame of the safety-lamp1 it was proposed by ,davy to suspend a coil of platinum which would be thus kept constantly at a red heat4 ,if the miner became accidentally enveloped in an atmosphere of fire-damp1 although the flame of his lamp might be extinguished1 the wire would continue to glow with sufficient brightness to light him from his danger1 through the dark winding passages which have been worked in the bed of fossil fuel4 ,this very beautiful arrangement has not1 however1 been adopted by our miners4 ,it is thus that the discoveries of science1 although they may appear of an abstract character1 constantly1 sooner or later1 are applied to uses by which some branch of human labour is assisted1 the necessities of man's condition relieved1 and the amenities of life advanced4 ,the respiration of animals is an instance of the same kind of chemical phenomena as we discover in ordinary combustion4 ,in the lungs the blood becomes charged with oxygen1 derived from the atmospheric air1 with which it passes through the system1 performing its important offices1 and the blood is returned to the lungs with the carbonic acid formed by the separation of carbon from the body which is thrown off at every expiration4 ,it will be quite evident that this process is similar to that of ordinary combustion4 ,in man or animals1 as in the burning taper1--which is aptly enough employed by poets as the symbol of life1--we have hydrogen and carbon1 with some nitrogen superadded2 the hydrogen and oxygen form water under the action of the vital forces2 the carbon with oxygen produces carbonic acid1 and1 by a curious process1 the nitrogen and hydrogen also combine1 to form ammonia4#bbb ,all the carbon which is taken into the animal economy passes1 in the process of time1 again into the atmosphere1 in combination with oxygen1 this being effected in the body1 under the catalytic power of tissues1 immediately influenced by the excitation of nervous forces1 which are the direct manifestations of vital energy4 ,the quantity of carbonic acid thus given out to the air is capable of calculation1 with only a small amount of error4 ,it appears that upwards of fifty ounces of carbonic acid must be given off from the body of a healthy man in twenty-four hours4 ,on the lowest calculation1 the population of ,london must add to the atmosphere daily #d1ejj1jjj pounds of carbonic acid4 ,it must also be remembered that in every process for artificial illumination1 and in all the operations of the manufactures in which fire is used1 and also in our arrangements to secure domestic comfort1 immense quantities of this gas are formed4 ,we may1 indeed1 fairly estimate the amount1 if we ascertain the quantity of wood and coal consumed1 of all the carbon which combines with oxygen while burning1 and escapes into the air1 either as carbonic acid or carbonic oxide4 ,the former gas1 the same as that which accumulates in deep wells and in brewers' vats1 is highly destructive to life1 producing very distressing symptoms1 even when mixed with atmospheric air1 in but slight excess over that proportion which it commonly contains4 ,the oppressive atmosphere of crowded rooms is in a great measure due to the increased proportion of carbonic acid given off from the lungs of those assembled1 and collected in the almost stagnant air of badly ventilated apartments4 ,it will be evident to every one1 that unless some provision was made for removing this deleterious gas from the atmosphere as speedily as it formed1 consequences of the most injurious character to the animal races would ensue4 ,it is found1 however1 that the quantity in the atmosphere is almost constantly about one per cent4 ,the peculiar properties of carbonic acid in part ensure its speedy removal4 ,it is among the heaviest of gaseous bodies1 and it is readily absorbed by water2 consequently1 floating within a short distance from the surface of the earth1 a large quantity is dissolved by the waters spread over it4 ,a considerable portion is removed by the vegetable kingdom2 indeed1 the whole of that produced by animals1 and by the processes of combustion1 eventually becomes part of the vegetable world1 being absorbed with water by the roots1 and separated from the air by the peculiar functions of the leaves4 ,however1 this heavy gas unites with the lighter atmospheric fluid in obedience to that law which determines the diffusion of different specific gravities through each other4 ,the leaves of plants may be regarded as performing similar offices to the lungs of animals4 ,they are the breathing organs4 ,in the animal economy a certain quantity of carbon is necessarily retained1 in combination with nitrogen and other elements1 to form muscle2 but this is constantly undergoing change2 the entire system being renewed within a comparatively limited period4 ,the conditions with plants are somewhat different4 ,for instance1 the carbon is fixed in a tree1 and remains as woody fibre until it decays1 even though the life of the plant may extend over centuries4 ,animals1 then1 are constantly supplying carbonic acid2 plants are as constantly feeding on it2 thus is the balance for ever maintained between the two kingdoms4 ,another condition is1 however1 required to maintain for the uses of men and animals the necessary supply of oxygen gas4 ,this is effected by one of those wonderful operations of nature's chemistry which must strike every reflecting mind with admiration4 ,during the night plants absorb carbonic acid2 but there is a condition of repose prevailing then in their functions1 and consequently their powers of effecting the decomposition of this gas are reduced to their minimum4 ,the plant sleeps1 and vital power reposes2 its repose being as necessary to the plant as to the animal4 ,with the first gleam of the morning sun the dormant energies of the plant are awakened into full action2 it decomposes this carbonic acid1 secretes the carbon1 to form the rings of wood which constitute so large a part of its structure1 and pour out oxygen gas to the air4 ,the plant is1 therefore1 an essential element in the conditions necessary for the support of animal life4 ,the animal produces carbonic acid in an exact proportion to the quantity of carbonaceous matter which it consumes4 ,fruit and herbage contain a small quantity of carbon in comparison with muscle and fat4 ,but let us confine our attention to the human race4 ,man within the ,tropics1 where the natural temperature is high1 does not require so great an amount of chemical action to go on within him for the purpose of maintaining the requisite animal heat2 consequently his ,maker has surrounded him with fruits and grains which constitute his food4 ,as we advance to the colder regions of the earth man becomes a flesh-eater1 and his carnivorous appetite increases as the external temperature diminishes4 ,eventually we reach the coldest zones1 and the human being there devours enormous quantities of fat to supply the necessities of his condition4 ,it must necessarily follow1 that the inhabitants of the tropics do not produce so much carbonic acid as those who dwell in colder regions4 ,in the first place1 their habits of life are different1 and they are not under the necessity of maintaining animal heat by the use of artificial combustion1 as are the people of colder climes4 ,the vegetation of the regions of the tropics is much more luxuriant than that of the temperate and arctic zones4 ,hence an additional supply of carbonic acid is required between the torrid zones1 and a less quantity is produced by its animals4 ,these cases are all met by the great arial movements4 ,a current of warmed air1 rich in oxygen1 moves from the equator towards the poles1 whilst the cooler air1 charged with the excess of carbonic acid1 sets in a constant stream towards the equator4 ,by this means the most perfect equalization of the atmospheric conditions is preserved4 ,the carbonic acid poured out from the thousand mouths of our fiery furnaces1--produced during the laborious toil of the hard-working artizan1--and exhaled from every populous town of this our island home1--is borne away by this our arial currents to find its place in the pines of the ,pacific ,islands1 the spice-trees of the ,eastern ,archipelago1 and the cinchonas of ,southern ,america4 ,the plants of the valley of the ,caucasus1 and those which flourish amongst the ,himalayas1 equally with the less luxuriant vegetation of our temperate climes1 are directly dependent upon man and the lower animals for their supply of food4 ,if all plants were removed from the earth1 animals could not exist4 ,how would it be if the animal kingdom was annihilated8--would it be possible for vegetation to continue8 ,this question is not quite so easily answered2 but1 if we suppose all the carbon-producing machines--the animals--to be extinct1 from whence would the plants draw their supply8 ,it has been supposed that during the epoch of the coal formation a luxuriant vegetation must have gone on over the earth's surface1 when the existence of animal life was regarded as problematical4 ,it is supposed that the air was then charged with carbonic acid1 and that the calamites1 lepidodendra1 and sigilaria1 were employed to remove it1 and fit the earth for the oxygen-breathing races4 ,the evidence upon these points is by no means satisfactory2 and although at one time quite disposed to acquiesce in a conjecture which appears to account so beautifully for the observed geological phenomena of carboniferous periods1 we do not regard the necessities for such a condition of the atmosphere as clearly made out4#bbc ,geological research1 too1 has shown that the immense forests from which our coal is formed teemed with life4 ,a frog as large as an ox existed in the swamps1 and the existence of insects proves the high order of organic creation at this epoch4 ,in all probability the same mutual dependence which now exists between the animal and vegetable kingdoms existed from the beginning of time1 and will continue to do so under varying circumstances through the countless ages of the earth's duration4 ,there is yet another very important chain of circumstances which binds these two great kingdoms together4 ,this is the chain of the animal necessities4 ,a large number of races feed directly upon vegetables2 herbs and fruits are the only things from which they gain those elements required to restore the waste of their systems4 ,these herbivorous animals1 which must necessarily form fat and muscle from the elements of their vegetable diet1 are preyed on by the carnivorous races2 and from these the carbon is again restored to the vegetable world4 ,sweep off from the earth the food of the herbivora1 they must necessarily very soon perish1 and with their dissolution1 the destruction of the carnivora is certainly ensured4 ,to illustrate this on a small scale1 it may be mentioned that around the coasts of ,cornwall1 pilchards were formerly caught in very great abundance1 in the shallow water within coves1 where these fish are now but rarely seen4 ,from the investigations of the ,messrs4 ,couch1 whose very accurate observations on the ,cornish fauna have placed both father and son amongst the most eminent of ,british naturalists1#bbd it appears that the absence of these fish is to be attributed entirely to the practice of the farmers1 who cut the sea-weed from the rocks for the purpose of manuring their lands4 ,by this they destroy all the small crustacea inhabiting these immature marine forests feeding on the alg1 and as these1 the principal food of the pilchards1 have perished they seek for a substitute in more favourable situations4 ,mr4 ,darwin remarks1 that if the immense sea-weeds of the ,southern ,ocean were removed by any cause1 the whole fauna of these seas would be changed4 ,we have seen that animals and vegetables are composed principally of four elementary principles1--oxygen1 hydrogen1 nitrogen1 and carbon4 ,we have examined the remarkable manner in which they pass from one condition--from one kingdom of nature--into another4 ,the animal1 perishing and dwindling by decomposition into the most simple forms of matter1 mingling with the atmosphere as mere gas1 gradually becomes part of the growing plant1 and by like changes vegetable organism progresses onward to form a portion of the animal structure4 ,a plant exposed to the action of natural or artificial decomposition passes into air1 leaving but a few grains of solid matter behind it4 ,an animal1 in like manner1 is gradually resolved into 8thin air40 ,muscle1 and blood1 and bones1 having undergone the change1 are found to have escaped as gases1 leaving only 8a pinch of dust10 which belongs to the more stable mineral world4 ,our dependency on the atmosphere is therefore evident4 ,we derive our substance from it--we are1 after death1 resolved again into it4 ,we are really but fleeting shadows4 ,animal and vegetable forms are little more than consolidated masses of the atmosphere4 ,the sublime creations of the most gifted bard cannot rival the beauty of this1 the highest and the truest poetry of science4 ,man has divined such changes by the unaided powers of reason1 arguing from the phenomena which science reveals in unceasing action around him4 ,the ,grecian sage's doubts of his own identity1 were only an extension of a great truth beyond the limits of our reason4 ,romance and superstition resolve the spiritual man into a visible form of extreme ethereality in the spectral creations1 8clothed in their own horror10 by which their reigns have been perpetuated4 ,when ,shakespeare made his charming ,ariel sing-- 8,full fathom five thy father lies1 ,of his bones are coral made1 ,those are pearls that were his eyes3 ,nothing of him that doth fade1 ,but doth suffer a sea change ,into something rich and strange10 he painted1 with considerable correctness1 the chemical changes by which decomposing animal matter is replaced by a siliceous or calcareous formation4 ,but the gifted have the power of looking through the veil of nature1 and they have revelations more wonderful than even those of the philosopher1 who evokes them by perpetual toil and brain-racking struggle with the ever-changing elements around him4 ,the mysteries of flowers have ever been the charm of the poet's song4 ,imagination has invested them with a magic influence1 and fancy has almost regarded them as spiritual things4 ,in contemplating their surpassing loveliness1 the mind of every observer is improved1 and the sentiments which they inspire1 by their mere external elegance1 are great and good4 ,but in examining the real mysteries of their conditions1 their physical phenomena1 the relations in which they stand to the animal world1 8stealing and giving odours0 in the marvellous interchange of carbonic acid and ammonia for the soul-inspiring oxygen--all speaking of the powers of some unseen1 in-dwelling principle1 directed by a supreme ruler--the philosopher finds subjects for deep and soul-trying contemplation4 ,such studies lift the mind into the truly sublime of nature4 ,the poet's dream is the dim reflection of a distant star3 the philosopher's revelation is a strong telescopic examination of its features4 ,one is the mere echo of the remote whisper of nature's voice in the dim twilight2 the other is the swelling music of the harp of ,memnon1 awakened by the sun of truth1 newly risen from the night of ignorance4 ,to return from our long1 but somewhat natural digression1 to a consideration of the chemical phenomena connected with the atmosphere1 and its curious and important element1 nitrogen1 we must first examine the evidence we have of the condition of the air itself4 ,the mean pressure exerted upon the surface of the earth1 as indicated by the barometer1 is equal to a column of mercury thirty inches high2 that is1 the column of air from the surface of the ocean to its highest limits exactly balances that quantity of mercury4 ,if our tube of mercury had the area of one square inch1 the columns would weigh fifteen pounds1 which represents a pressure of fifteen pounds upon every square inch of the earth's surface4 ,this pressure1 it must be remembered1 is the compound weight of the gaseous envelope1 and the elastic force of the aqueous vapour contained in it4#bbe ,if the atmosphere were of uniform condition1 its height1 as inferred from the barometer1 would be about five miles and a half4 ,the density of the air1 however1 diminishes with the pressure upon it1 so that at the height of #aa1eef feet1 the atmosphere is of half density2 or one volume of air1 as taken at the surface of the earth1 is expanded into two at that height4 ,thus the weight is continually diminishing2 but this is regularly opposed by the decreasing temperature1 which diminishes the rate of about one degree for every #ceb feet of ascent1 although in all probability it is less rapid at great distances from the earth4 ,it has been calculated from certain phenomena of refraction1 that our atmosphere must extend to about forty miles from the surface of the earth4 ,it may1 in a state of extreme tenuity1 extend still further2 but it is probable that the intense cold produced by rarefaction sets limits to any extension much beyond this elevation4 ,the uses of the atmosphere are many4 ,it is the medium for regulating the dispersion of watery vapours over the earth4 ,if there were no atmosphere1 and that1 as now1 the equatorial climes were hot and the poles cold1 evaporation would be continually going on at the equator1 and condensation in the colder regions4 ,the sky of the tropical climes would be perpetually cloudless1 whilst in the temperate and arctic zones we should have constant rain and snow4 ,by having a gaseous atmosphere1 a more uniform state of things is produced2 the vapours arising from the earth become intimately mixed with the air1 and are borne by it over large tracts of country1 and only precipitated when they enter some stratum much colder than that which involves them4 ,there are opposite tendencies in an atmosphere of air and one of vapour4 ,the air circulates from the colder to the warmer parts1 and the vapour from the warmer to the colder regions2 and as the currents of the air1 from the distribution of land and sea--the land1 from its low conducting power1 being more quickly heated than the sea--are very complicated1 and as some force is employed in keeping the vapour suspended in the air1 water is less suddenly deposited on the earth than it would have been1 had not these tendencies of the air and its hygrometric peculiarities been such as we find them4 ,the blue colour of the sky1 which is so much more agreeable to the eye than either red or yellow1 is due to a tendency of the mixed gas and vapour to reflect the blue rays rather than red or yellow4 ,the white light which falls upon the surface of the earth1 without absorption or decomposition in its passage from the sun1 is partially absorbed by1 and in part reflected back from1 the earth4 ,the reflected rays pass with tolerable freedom through this transparent medium1 but a portion of the blue rays are interrupted and rendered visible to us4 ,that it is reflected light1 is proved by the fact of its being in a polarized state4#bbf ,clouds of vapour reflect to us again1 not isolated rays1 but the undecomposed beam1 and consequently they appear white as snow to our vision4 ,the golden glories of sunset1--when1 8like a dying dolphin10 heaven puts on the most gorgeous hues1 which are continually changing1--depend entirely upon the quantity of watery vapour which is mixed with air1 and its state of condensation4 ,it has been observed1 that steam at night1 issuing into the atmosphere under a pressure of twenty or thirty pounds to the square inch1 transmits and reflects orange-red light4 ,this we may1 therefore1 conclude to be the property of such a condition of mixed vapour and air1 as prevails when the rising or the setting sun is shedding over the eastern or the western horizon the glory of its coloured rays4#bbg ,thus science points out to us the important uses of the air4 ,we learn that life and combustion are entirely dependent on it1 and that it is made the means for securing greater constancy in the climates of the earth than could otherwise be obtained4 ,the facts already dwelt upon are sufficient to convince every thinking mind that the beautiful system of order which is displayed in the composition of the atmosphere1 in which the all-exciting element1 oxygen1 is subdued to a tranquil state by another element1 nitrogen1 7which1 we shall have presently to show1 is itself1 under certain conditions1 one of the most energetic agents with which we are acquainted17 indicates a supreme power1 omniscient in the adaptation of things to an especial end4 ,oxygen and nitrogen are here mixed for the benefit of man2 man unites them by the aid of powers with which he is gifted1 and the consequences are of a fatal kind4 ,the principles which the great ,chemist of ,nature renders mild are transformed into sources of evil by the chemist of art4 ,beyond all this1 the atmosphere produces effects on light which add infinitely to the beauty of the world4 ,were there no atmosphere1 we should only see those objects upon which the sun's rays directly fell1 or from which they were reflected4 ,a ray falling through a small hole into a dark room1 illuminating one object1 which reflects some light upon another1 is an apt illustration of the effect of light upon the earth1 if it existed without its enveloping atmosphere4 ,by the dispersive powers of this medium1 sunlight is converted into daylight2 and instead of unbearable1 parallel rays illuminating brilliantly1 and scorching up with heat those parts upon which they directly fall1 leaving all other parts in the darkness of night1 we enjoy the blessings of a diffusion of its rays1 and experience the beauties of soft shades and slowly-deepening shadows4 ,without an atmosphere1 the sun of the morning would burst upon us with unbearable brilliancy1 and leave us suddenly1 at the close of day1 at once in utter darkness4 ,with an atmosphere we have the twilight with all its tempered loveliness1--a 8time for poets made40 ,in chemical character1 atmospheric air is composed of twenty-one volumes of oxygen1 and seventy-nine volumes of nitrogen3 or one hundred grains of air consist of #bca grains of the former1 and #gfi grains of the latter4 ,whether the air is taken from the greatest depths or the most exalted heights to which man has ever reached1 an invariable proportion of the gases is maintained4 ,the air of ,chimborazo1 of the arid plains of ,egypt1 of the pestilential delta of the ,niger1 or even of the infected atmosphere of an hospital1 all give the same proportions of these two gases as we find existing on the healthful hills of ,devonshire1 or in the air of the city of ,london4 ,this constancy in constitution leads to the supposition that the oxygen and nitrogen are chemically combined2 but many eminent philosophers have contended that they are merely mechanically mixed2 and they have shown that some peculiar properties prevail amongst gaseous bodies1 which very fully explain the equal admixture of two gases the specific gravities of which are different4 ,this is particularly exemplified in the case of carbonic acid1 of which gas one per cent4 can be detected in all regions of the air to which the investigations of man have reached4 ,this gas1 although so heavy1 is1 by the law of diffusion1 mixed with great uniformity throughout the mass4#bbh ,every exhalation from the earth1 of course1 passes into the air2 but these are generally either so light that they are carried into the upper regions1 and there perform their parts in the meteorological phenomena1 or they are otherwise very readily absorbed by water or growing plants1 and thus is the atmosphere preserved in a state of purity for the uses of animals4 ,again1 the quantity of oxygen contained in the air1 and its very peculiar character1 ensures the oxidation of all the volatile organic matters which are constantly passing off1--as the odoriferous principles of plants1 the miasmata of swamps1 and the products of animal putrefaction2 these are rapidly converted into water1 carbonic acid1 or nitric acid1 and quickly enter into new and harmless combinations4 ,the elements of contagion we are unacquainted with2 but since the attention of inquirers has been of late directed to this important and delicate subject1 some light may possibly be thrown upon it before long4 ,nothing1 shows more strikingly the admirable adaptation of all things for their intended uses than the atmosphere4 ,in it we find the source of life and health2 and chemistry teaches us1 most indisputably1 that it is composed of certain proportions of oxygen and nitrogen gases2 and experience informs us that it is on the oxygen that we are dependent for all that we enjoy4 ,so beautifully is the atomic or molecular constitution ordered1 that it is impossible to produce any change in the air without rendering it injurious to the vegetable and animal economy4 ,it might be thought1 from the well-known exhilirating character of oxygen gas1 that1 if a larger quantity existed in the atmosphere than that which we find there1 the enjoyments of life would be of a more exciting kind2 but the consequences of any increase would be exceedingly injurious2 and1 by quickening all the processes of life to an unnatural extent1 the animal fabric would soon decay3 excited into fever1 it would be destroyed by its own fires4 ,chemistry has made us acquainted with six other compounds of oxygen and nitrogen1 neither of them fitted for the purposes of vitality1 of which the following are the most remarkable3-- ,nitrous oxide1 or the1 so called1 laughing gas1 which contains two volumes of nitrogen to one of oxygen1 would prove more destructive than even pure oxygen1 from the delirious intoxication which it produces4 ,nitric oxide is composed1 according to ,davy1 of two volumes of nitrogen and two of oxygen4 ,it is of so irritating a nature1 that the glottis contracts spasmodically when any attempt is made to breathe it2 and the moment it escapes into the air it combines with more oxygen1 and forms the deep red fumes of nitrous acid4 ,nitrous acid and the peroxide of nitrogen each contains an additional proportion of oxygen1 and they are still more destructive to all organization4 ,nitric acid contains five volumes of oxygen united to two of nitrogen2 and the well-known destructive properties of aqua fortis it is unnecessary to describe4 ,the atmosphere1 and these chemically active compounds1 contain the same elements1 but their mode of combining is different2 and what is1 in the one case1 poisonous to the highest degree1 is1 in the other1 rendered salubrious1 and essential to all organized beings4 ,nitrogen gas may be regarded in the light of a diluent to the oxygen4 ,in its pure state it is only characterised by its negative properties4 ,it will not burn1 or act as a supporter of combustion4 ,animals speedily perish if confined in it2 but they die rather through the absence of oxygen than from any poisonous property of this gas4 ,yet1 in combination1 we find nitrogen exhibiting powers of a most energetic character4 ,in addition to the fulminating compounds and the explosive substances already named1 which are among the most remarkable instances of unstable affinity with which we are acquainted1 we have also the well-known pungent body1 ammonia4 ,from the analogous nature of this volatile compound1 and the fixed alkalies soda and potash1 it was inferred that it must1 like them1 be an oxide of a metallic base4 ,davy exposed ammonia to the action of potassium1 and to the influence of the voltaic arc produced from #b1jjj double plates1 without at all changing its character4 ,from its slight tendency to combination1 and from its being found abundantly in the organs of animals feeding on substances that do not contain it1 it is1 however1 probably a compound body4 ,a phenomenon of an obscure and mysterious character is presented in the formation of the 8ammoniacal amalgam10 as it is called4 ,mercury1 being mixed with an ammoniacal salt1 is exposed to powerful galvanic action2 and a compound1 maintaining its metallic appearance1 but of considerable lightness and very porous1 presents itself4#bbi ,this preparation has been carefully examined by ,davy1 ,berzelius1 and others4 ,it is always resolved into ammonia and mercury2 and1 although the latter chemist is strongly inclined to regard it as affording evidence of the compound nature of nitrogen1--and he has1 indeed1 proposed the name nitricum for its hypothetical base1--yet1 to the present time1 we have no satisfactory explanation of this apparent metallization of ammonia4 ,no attempt will be made to describe the various elementary substances which come under the class of metallic bodies1 much less to enumerate their combinations4 ,many of the metals1 as silver and copper1 are found sometimes in a native state1 or nearly pure2 but1 for the most part1 they exist1 in nature1 in combination with oxygen or sulphur2 gold furnishing a remarkable exception4 ,they are occasionally found combined with other bodies1--as oxidized carbon1 phosphorus1 chlorine1 c42 but these cases are by no means so common4 ,those substances called metals are generally found embedded in the rocks1 or deposited in fissures formed through them2 but it is one of the great discoveries of modern science1 that those rocks themselves are metallic oxides4 ,with metals we generally associate the idea of great density2 but potassium and sodium1 the metallic bases of potash and soda1 are lighter than water1 and they consequently float upon that fluid4 ,we learn1 therefore1 from the researches of science1 that the crust of this earth is composed entirely of metals1 combined with gaseous elements2 and there is reason for believing that one1 or perhaps two1 of the gases we have already named are also of a metallic character4 ,strange as it may appear1 there is nothing1 as will be seen on attentive consideration1 irrational in this idea4 ,many of the metals proper1 under the influence of such heat as we can1 by artificial means1 command1 are dissipated in vapour1 and may be maintained in this state perfectly invisible4 ,indeed1 the transparent space above the surface of the mercury in the tube of a barometer1 known as the ,torricellian vacuum1 is filled with the vapour of mercury4 ,there is1 therefore1 no reason why nitrogen1 or even hydrogen1 should not be metallic molecules kept by the force of the repulsive powers of heat1 or some other influence1 at a great distance from each other4 ,the peculiar manner in which nitrogen unites with mercury1 and the property which hydrogen possesses of combining with antimony1 zinc1 arsenic1 potassium1 sodium1 and possibly other metals1 besides its union with sulphur and carbon--in all which cases there is no such change of character as occurs when they combine with oxygen--appear to indicate bodies which1 chemically1 are not very dissimilar to those metals themselves1 although1 physically1 they have not the most remote resemblance4 8,we know nothing10 says ,davy1 8of the true elements belonging to nature2 but1 so far as we can reason from the relations of the properties of matter1 hydrogen is the substance which approaches nearest to what the elements may be supposed to be4 ,it has energetic powers of combination1 its parts are highly repulsive as to each other1 and attractive of the particles of other matter2 it enters into combination in a quantity very much smaller than any other substance1 and in this respect it is approached by no known body40#bcj ,many of the elements are common to the three kingdoms of nature3 most of those found in one condition of organization are discovered in another4 ,the carbonates are an abundant mineral class4 ,in the vegetable kingdom we find carbon combining with oxygen1 hydrogen1 and nitrogen3 these elements1 also1 constitute the substance of animals1 the proportion of nitrogen being1 however1 much larger4 ,if one element1 more than another1 belongs especially to the animal economy1 it is phosphorus1 although this is not wanting in the vegetable world2 and it is not uncommon in the mineral4 ,sulphur is common to the three kingdoms3 it is abundant in the mineral1 being one of the products of volcanic action2 it is united with the metals1 forming sulphurets2 and is found in our rocks in the state of sulphuric acid or oxidized vapour1 combined with the metallic bases of lime and other earths4 ,in the vegetable kingdom we discover sulphur in all plants of the onion kind1 in the mustard1 and some others2 it enters into the composition of vegetable albumen1 and appears always combined with albumen1 fibrine1 and caseine1 in the animal economy4 ,chlorine is found most abundantly in combination with sodium1 as common salt3 in this state1 in particular1 we may trace it from the depths of the earth1 its waters1 and its rocks1 to the plants and animals of the surface4 ,iodine is most abundant in marine plants2 but it has been found in the mineral world1 traced to plants1 and it is indicated in the flesh of some animals4 ,bromine is known to us as a product of certain saline waters1 and a few specimens of natural bromide of silver have been examined4 ,fluorine1 the base of the acid which1 combining with lime1 forms fluor-spar1 is found to exist to some considerable extent in bones2 it has been discovered in milk and blood2 and investigations have proved its existence in the vegetable world4 ,it must not be forgotten that the earths1 lime and magnesia1 enter into the composition of the more solid parts of plants and animals4 ,lime is one of the principal constituents of animal bone and shells1 and it is found in nearly all vegetables4 ,silica1 or the earth of flints1 is met with in beautiful transparent crystals1 in the depths of the mine2 in all rock and soils we find it4 ,in the bark of many plants1 particularly the grasses1 it is discovered1 forming the hard supporting cuticle of the stalk1 in wheat1 the ,dutch rush1 the sugar-cane1 the bamboo1 and many other plants4 ,it is thus that we find the same elementary principle presenting itself in every form of matter1 under the most ,protean shapes4 ,numerous phenomena of even a more striking character than those selected1 are exhibited in every department of chemistry2 but within the limits of this essay it is impracticable to speak of any beyond those which directly explain natural phenomena4 ,the chemical elements1 which actually exist in nature as simple bodies1 are probably but few4 ,most of the gases are in all probability compounds of some ethereal ultimate principles2 and with the advance of science we may fairly hope to discover the means of reducing some of them to a yet more simple state4 ,curious relations1 which can be traced through certain bodies1 lead us to believe that they may be only modified conditions of one element4 ,flint and charcoal do not at first appear allied2 but carbon in some of its states approaches very near to the condition of silicon1 the metallic base of flint4 ,when we remember the differences which are evident in three forms of one body--coke1 graphite1 and diamond--the dissimilitude between flint1 a quartz crystal1 and carbon1 will cease to be a strong objection to the speculation4 ,phosphorus1 sulphur1 and selenium1 have many properties in common4 ,iodine1 bromine1 chlorine1 and fluorine1 appear to belong to the same group4 ,iron and nickel1 and cobalt1 have a close relation4 ,silver and lead are usually combined1 and exhibit a strong relationship4 ,gold1 platinum1 and the rarer metals1 have so many properties in common1 that they may form a separate group from all the others4 ,indeed1 a philosophical examination of the elements now supposed to constitute the material world1 enables us to divide them into about six well-defined groups4 ,wide differences exist within these groups2 but still we find a sufficient number of common properties to warrant our classing them in one family4 ,the dream of the alchemists1 in the vain endeavour to realise which they exhausted their lives and dissipated their wealth1 had its foundation in a natural truth4 ,the transmutation of one form of matter into another may be beyond the power of man1 but it is certainly continually taking place in the laboratory of nature1 under the directing law of the great ,creator of this beautiful earth4 ,the speculations of men1 through all ages1 have leaned towards this idea1 as is shown by the theory of the four elements1--,air1 ,fire1 ,earth1 and ,water1--of the ancients1 the three1--,salt1 ,sulphur1 and ,mercury1--of the alchemists1 and the refined speculations of ,newton and ,boscovich on the ultimate constitution of matter4 ,all experimental inquiry points towards a similar conclusion4 ,it is true we have no direct evidence of any elementary atom actually undergoing a change of state2 but when we regard the variations produced by electrical influence1 the changes of state which arise from the power of heat1 and the physical alterations produced by light1 it will be difficult to come to any other conclusion than that the particles of matter known to us as ultimate are capable of change1 and consequently must be far removed from positively simple bodies1 since the real elementary atom1 possessing fixed properties1 cannot be supposed capable of undergoing any transmutation4 ,allotropism could not occur in any absolutely simple body4 ,it will now be evident that in all chemical phenomena we have the combined exercise of the great physical forces1 and evidences of some powers which are1 as yet1 shrouded in the mystery of our ignorance4 ,the formation of minerals within the clefts of the rocks1 the decomposition of metallic lodes1 the germination of seeds1 the growth of the plant1 the development of its fruit and its ultimate decay1 the secret processes of animal life1 assimilation1 digestion1 and respiration1 and all the changes of external form1 which take place around us1 are the result of the exercise of that principle which we call chemical4 ,by chemical action plants take from the atmosphere the elements of their growth2 these they yield to animals1 and from these they are again returned to the air4 ,the viewless atmosphere is gradually formed into an organized being1 the lordly tree upon whose branches the fowls of the air have their homes1 and the human animal1 exalted by being charged with a spiritual soul3 yet the tree and the man alike are gradually resolved again into thin air4 ,the changes of the mineral world are of an analogous character2 but we cannot trace them so clearly in all their phenomena4 ,the planet on which we live began its course charged with a fixed quantity of physical force1 and this has remained constant to the present moment1 and will do so to the end of time4 ,by influences external to this earth the balance of these forces is continually disturbed2 and in the effort to restore the equilibrium1 we have the production of all the varied forms of matter1 and the manifestation of each particular physical principle or power4 ,as motion and attraction1 balanced against each other1 maintain the earth in her elliptical orbit1 so the opposition of forces determines the existence of the amorphous rock1 the light-refracting crystal1 the fixed and flowering plant1 and the locomotive animal4 ,an eternal round of chemical action is displayed in nature4 ,life and death are but two phases of its influences4 ,growth and decay are equally the result of its power4 ,,footnotes3 #bab ,dr4 ,priestley appears to have been the first to observe the peculiar property of the diffusion of gases4 ,dr4 ,dalton1 however1 first drew attention to the important bearing of this fact on natural phenomena1 and he published his views on ,the ,miscibility of ,gases in the ,manchester ,memoirs1 vol4 v4 ,the following extract from his memoir ,on the ,constitution of the ,atmosphere will exhibit its bearings3-- ,it may be worth while to contrast this view of the constitution of the atmosphere with the only other one1 as far as ,i know1 that has been entertained4 ,according to one view1 ,according to the other view1 #a4 ,the volumes of each gas #a4 ,the volume of each gas found at the surface of the found at the surface of earth are proportional to the earth1 multiplied by the whole weights of the its specific gravity1 is respective atmospheres4 proportional to the whole weight of the respective atmospheres4 ,azote #gi ,azote #gff ,oxygen #ba ,oxygen #bcd ,aqueous vapour #acc ,aqueous vapour #jhc ,carbonic acid #aj ,carbonic acid #jae ------- ------ #ajadc #ajjhh #b4 ,the altitude of each #b4 ,the altitude of each atmosphere differs from that atmosphere is the same1 and of every other1 and the the proportion of each in the proportions of each in the compound atmosphere1 is the compound atmosphere gradually same at all elevations4 vary in the ascent4 #c4 ,when two atmospheres are #c4 ,when two atmospheres mixed1 they take their places are mixed1 they continue according to their specific so without the heavier gravity1 not in separate manifesting any disposition to strata1 but intermixedly4 separate and descend from the ,there is1 however1 a separate lighter4 stratum of the specifically lighter atmosphere at the summit over the other4 #bac ,the discussion of this question1 commenced by ,arago in his ,eloge1 was continued by ,lord ,brougham in his ,lives of ,watt and ,cavendish1 and by ,mr4 ,vernon ,harcourt1 in his address as ,president of the ,british ,association1 and more recently in his ,letter to ,lord ,brougham4 ,watt's ,letters on the subject have been since published under the superintendence of ,mr4 ,muirhead4 #bad ,see several papers ,on ,ozone1 by ,professor ,schnbein1 in the ,philosophical ,magazine1 and in the ,reports of the ,british ,association4 ,consult a paper by the ,author3 ,athenum1 ,september1 #ahdi4 #bae ,memoire sur l',ozone2 ,ble #ahdi4 ,poggendorff's ,annalen1 lxxvii41 p4 #eib4 ,ibid1 lxxviii4 p4 #afb4 #baf ,chemical ,gazette1 #ahdi4 #bag ,iodide of silver has been found at ,albarradon1 near ,mazapil1 in ,mexico4 ,iodide of mercury1 of a fine lemon-yellow colour1 has been discovered in the sandstone of ,casas1 ,viegas1 ,mexico4 ,algers2 ,phillips' ,mineralogy4 #bah ,,gentele',s ,reports of the ,stockholm ,academy4 #bai ,stahl1 taking up the obscure notions of ,becher and ,van ,helmont1 supposed the phenomena of combustion to be due to phlogiston4 ,he imagined that by combination with phlogiston1 a body was rendered combustible1 and that its disengagement occasioned combustion1 and after its evolution there remained either an acid or an earth3 thus sulphur was1 by this theory1 supposed to be composed of phlogiston and sulphuric acid1 and lead of the calx of lead and phlogiston1 c4 #bbj ,being called upon by the ,solicitor for the ,admiralty to examine into the causes of the fire which destroyed the ,imogene and ,talavera1 in ,devonport ,arsenal1 ,i discovered a bin under the roofing which covered these ships1 in which there had been accumulating for a long period all the refuse of the wheelwrights' and painters' shop2 and it was quite evident that spontaneous combustion had taken place in the mass of oiled oakum1 sawdust1 anti-attrition1 and old sail-cloth1 there allowed to accumulate4 #bba ,researches on ,flame3 ,sir ,h4 ,davy's ,collected ,works4 #bbb ,see note1 ante1 ,on the ,chemical ,theory of ,respiration4 #bbc ,at the request of the ,british ,association1 a committee undertook the investigation of this subject4 ,experiments were carried on by ,dr4 ,daubeny1 in the ,botanic ,gardens at ,oxford1 and by the ,author1 at his residence1 ,stockwell4 ,dr4 ,daubeny1 in his report made at the meeting of the ,british ,association at ,birmingham1 appears disposed to consider ten per cent4 of carbonic acid in excess as destructive to the growth of ferns4 ,i found1 however1 that1 by gradually increasing the quantity1 the ferns would live in an atmosphere still more highly charged with carbonic acid4 #bbd ,see memoir ,on the ,pilchard1 by ,mr4 ,couch1 in the ,reports of the ,royal ,cornwall ,polytechnic ,society4 #bbe 8,this scale1 in which the humidity of the air is expressed1 is the simple natural scale in which air at its maximum of humidity 7i4e41 when it is saturated with vapour7 is reckoned as #ajj1 and air absolutely deprived of moisture as #j2 the intermediate degrees are given by the fraction #ajj actual tension of vapour tension required for the saturation of the air at its existing temperature4 ,thus1 if the air at any temperature whatsoever contains vapour of half the tension1 which it would contain if saturated1 the degree is #ej2 if three-fourths1 then #ge2 and so forth4 ,air of a higher temperature is capable of containing a greater quantity of vapour than air of less temperature2 but it is the proportion of what it does contain1 to what it would contain if saturated1 which constitutes the measure of its dryness or humidity4 ,the capacity of the air to contain moisture being determined by its temperature1 it was to be expected that an intimate connection and dependence would be found to exist between the annual and diurnal variations of the vapour and of the temperature40--,sabine1 ,on the ,meteorology of ,toronto2 ,reports of the ,british ,association1 vol4 xiii4 p4 #dg4 ,the ,temperature ,tables3 by ,prof4 ,w4 ,h4 ,dove2 ,reports for #ahdg should be consulted4 #bbf ,sir ,david ,brewster's ,optics1 and ,memoirs in the ,philosophical ,transactions4 ,sir ,john ,herschel's ,treatise on ,light1 ,encyclopdia ,metropolitana4 #bbg ,on the ,colour of ,steam under certain circumstances3 by ,professor ,forbes2 ,philosophical ,magazine1 vol4 xiv4 p4 #aba1 vol4 xv4 p4 #be4 ,in the first paper the following remarks occur3--8,i cannot doubt that the colour of watery vapour under certain circumstances is the principal or only cause of the red colour observed in clouds4 ,the very fact that that colour chiefly appears in the presence of clouds is a sufficient refutation of the only explanation of the phenomena of sunset and sunrise1 having the least plausibility1 given by optical writers4 ,if the red light of the horizontal sky were simply complementary to the blue of a pure atmosphere1 the sun ought to set red in the clearest weather1 and then most of all2 but experience shows that a lurid sunrise or sunset is always accompanied by clouds or diffused vapours1 and in a great majority of cases occurs when the changing state of previously transparent and colourless vapour may be inferred from the succeeding rain4 ,in like manner1 terrestrial lights seen at a distance grow red and dim when the atmosphere is filled with vapour soon to be precipitated4 ,analogy applied to the preceding observations would certainly conduct to a solution of such appearances2 for ,i have remarked that the existence of vapour of high tension is by no means essential to the production of colour1 though of course a proportionally greater thickness of the medium must be employed to produce a similar effect when the elasticity is small40 #bbh ,on the ,law of ,diffusion of ,gases3 by ,thomas ,graham1 ,m4,a41 ,f4,r4,s41 c42 ,edinburgh ,philosophical ,transactions1 #ahcb4 ,sur l',action ,capillaire des ,fissures1 c43 by ,dbereiner2 ,annales de ,chimie1 xxiv4 #ccb4 #bbi ,electro-chemical ,researches on the ,decompositions of the ,earths1 with observations on the ,metals obtained from the ,alkaline ,earths1 and on the ,amalgam procured from ,ammonia3 by ,sir ,humphry ,davy2 ,philosophical ,transactions1 #ahjh1 and collected works1 vol4 v4 p4 #ajb4 #bcj ,elements of ,chemical ,philosophy3 by ,sir ,h4 ,davy4 ,,chapter ,,xiii4 ,,time4--,,geological ,,phenomena4 ,time1 an element in ,nature's ,operations--,geological ,science--,its ,facts and ,inferences--,nebular ,hypothesis applied--,primary ,formations--,plutonic and ,metamorphic ,rocks--,transition ,series--,palozoic ,rocks--,commencement of ,organic ,arrangements--,existence of ,phosphoric ,acid in ,plutonic ,rocks--,fossil ,remains--,coal ,formation--,sandstones--,tertiary ,formations--,eocene1 ,miocene1 and ,pliocene ,formations--,progressive changes now apparent--,general ,conclusions--,physics applied in explanation4 ,the influence of time1 as an element1 in producing certain structural arrangements1 by modifying the operations of physical force1 under whatever form it may be exerted1 has scarcely been sufficiently attended to in the examination of cosmical phenomena4 ,every particle of matter is1 as it were1 suspended between the agencies to which we have been directing our attention4 ,under the influences of the physical powers1 sometimes exerted in common1 but often with a great preponderance in favour of one of them1 every accumulated heap of mud or sand is slowly cohering1 and assuming the form of a rock possessing certain distinguishing features1 as it regards lamination1 cleavage1 c4 ,the minute particles of matter are necessarily but slightly influenced by the physical forces3 their action in accordance with the laws which determine physical condition is manifested in an exceedingly modified degree4 ,but in all the operations of nature1 what is deficient in power is made up in time1 and effects are produced during myriads of ages1 by powers far too weak to give satisfactory results by any experiments which might be extended even over a century4 ,if1 with the eye of a geologist1 we take but a cursory glance over the ,earth1 we shall discover that countless ages must have passed during the progress of this planet to its present state4 ,this is a fact written by the finger of nature1 in unmistakeable characters1 upon the mighty tablets of her mountains4 ,the superficial crust of the earth1--by which is meant only that film1 compared with its diameter1 which is represented by a few miles in depth--is composed of distinct mineral masses1 exhibiting peculiar physical conditions and a certain order of arrangement4 ,these rocks appear to have resulted from two dissimilar causes2 in one class the action of heat is evident1 and in the other we have either the slow deposition of matter suspended in water1 or crystallization from solution2 an aqueous origin is indicated by peculiarities of formation in all the more recent rocks4 ,there are few branches of science which admit of speculation to the extent to which we find it carried in geology4 ,the consequences of this are shown in the popular character of the science4 ,a few observations are made over a limited area1 and certain structural conditions are ascertained1 and at once the mind1 8fancy free10 penetrates the profound depths of the earth1 and imagination1 having 8ample room and verge enough10 creates causes by which every effect is to be interpreted4 ,such students1 generally ignorant of the first principles of physics1 knowing little of mineralogy1 and less of chemistry1 to say nothing of palontology1 having none of the requisites for an observer1 boldly assume premises which are untenable1 and think they have explained a phenomenon1--given to the world a truth1--when they have merely promulgated an unsubstantiated speculation1 which may have occasional marks of ingenuity1 and but little else4 ,the carefully-made observations of those who1 with unwearying industry1 have traversed hill and valley1 marked and measured the various characters1 thicknesses1 inclinations1 and positions of rocks2 who have watched the influences of heat in changing1 of water in wearing1 and the results of precipitation in forming1 strata2 who have traced the mechanical effects of earthquake strugglings and of volcanic eruptions1 and1 reasoning from an immense mass of accumulated facts1 deduced certain general conclusions1--are1 however1 of a totally different character2 and it is such observers as these who induced ,herschel to say truly1 that 8geology1 in the magnitude and sublimity of the objects of which it treats1 undoubtedly ranks1 in the scale of the sciences1 next to astronomy40#bca ,the origin of this planet is involved in great obscurity1 which the powers of the most gifted are unable to penetrate4 ,it stands the work of an ,almighty and ,eternal mind1 the beginning of which we cannot comprehend1 nor can we define the period of its termination4 ,it may1 probably1 be safe to speculate that there was a time when this globe consisted of only one homogeneous stratum4 ,whether this remains1--whether1 in our plutonic rocks1 our granites1 or our porphyries1 we have any indications of the primitive state of the world1 or whether numerous changes took place before even our unstratified formations had birth1 are questions we cannot answer4 ,the geologist looks back into the vista of time1 and reckons1 by phenomena1 the progress of the world's mutations4 ,the stratified formations must have occupied thousands of ages2 but before these were1 during a period extending over countless thousands1 the unstratified rocks may have been variously metamorphosed4 ,it matters not whether we admit the nebular hypothesis or not1--a time must have been when all these bodies which now form the mass of this globe existed in the most simple state4 ,we have already shown that very remarkable changes in external character and in chemical relations are induced1 in the same simple element1 by its having been exposed to some peculiar and different conditions2 and already have we speculated on the probability that the advance of science will enable us to reduce the numerous elements we now reckon1 to two or three4 ,it is1 therefore1 by no means an irrational thought 7which must1 however1 be held in the light of a pure conjecture71 to suppose that at the beginning a mighty mass of matter1 in the most attenuated state1 was produced in space1 and was gradually1 under the influence of gravitation1 of cohesive force1 and of chemical aggregation1 moulded into the form of a sphere4 ,ascending to the utmost refinement of physics1 we may suppose that this mass was of one uniform character1 and that it became in dissimilar parts--its surfaces and towards its centre--differently constituted1 under the influences of the same powers which we now find producing1 out of the same body1 charcoal and the diamond1 and creating the multitudinous forms of organized creations4 ,these conditions being established1 and carried to an extent of which1 as yet1 science has afforded us no evidence1 chemical intermixture may have taken place1 and a new series of compounds have been formed1 which1 by again combining1 gave rise to another and more complex class of bodies4 ,the foundation of the superficial crust of the earth appears to be formed of a class of rocks which have resulted from the slow cooling of an immense mass of heated matter4 ,these rocks have been called igneous2 but are now more generally termed ,plutonic 7such as granites1 syenites1 c47 ,immediately above these1 we find rocks which have resulted by deposition from water4 ,these masses1 having been exposed to the action of the heat below1 have been considerably changed in their character1 and hence they are often called metamorphic2 but metamorphic rocks may1 however1 be of any age4 ,the rocks formerly termed the transition series--from their forming the connecting link between the earlier formations--are now1 from the circumstance of their being fossiliferous1 classed under the general term of palozoic rocks1 to distinguish them from the rocks in which no organic remains have been found4 ,above these are found the secondary strata1 and1 still more recently produced1 we have a class now usually denominated the tertiary formations4 8,eternal as the hills0 is a poetic expression1 implying a long duration2 but these must1 from the nature of things1 eventually pass away4 ,the period of time necessary for the disintegration of a granite hill is vastly beyond the powers of computation1 according to our conception of the ordinary bounds of finite things4 ,but a consideration of the results of a few years1--under the influence of the atmosphere and the rains1--as shown in quantity of solid matter carried off by the rivers1 and deposited at their mouths1 will tend to carry conviction to every mind1 that a degrading process is for ever in action on the surface of the earth4 ,the earth itself may be eternal1 but the surface is continually undergoing mutation1 from various causes1 many of which we must briefly consider4#bcb ,in regarding geological phenomena1 the absence of any fossil remains has often been supposed to indicate a period previous to any organic formations4 ,the inorganic constituents of matter are probably of prior origin to the organic combinations2 the vessel was constructed1 upon which the organic creation was to float in space before any vital organisms were created4 ,the supposed evidences in favour of the assumption that there was no organic life during the formation of the oldest rocks we know1 are in some respects doubtful2 and we can well understand that changes may have been induced in the earlier rock formations1 by heat or by other powers1 quite sufficient to destroy all traces of organized forms4 ,it was long thought that phosphoric acid was not to be detected in rocks which are regarded as of igneous origin2 and since this acid is peculiarly a constituent of organic bodies1 this has been adduced as a proof that the plutonic rocks must have existed previously to the appearance of vegetable or animal life upon the surface of the globe4 ,the researches of modern chemists have1 however1 shown that phosphoric acid is to be found in formations of granitic origin1 in porphyry1 basalt1 and hornblende rocks4#bcc ,if1 therefore1 we are to regard this substance as of organic origin1 the rational inference is against the speculation2 but there is no more necessity for supposing phosphorus to be formed in the animal economy than in the mineral kingdom1 from which it will probably be found the animal obtained it4 ,without attempting to enter into any account of the apparent progress of life over the earth1 it appears desirable that some description should be given of the kinds of plants and animals which we know to have existed at different epochs4 ,we shall thus learn1 at least1 some of the prevailing characteristics of the earth during its transitions1 and be in a better condition for applying our knowledge of physical power to the explanation of the various geological phenomena4 ,among the earliest races we have those remarkable forms1 the trilobites1 inhabiting the ancient ocean4 ,these crustacea bear some resemblance1 although a very remote one1 to the common wood-louse1 and1 like that animal1 they had the power of rolling themselves into a ball when attacked by an enemy4 ,the eye of the trilobite is a most remarkable organ2 and in that of one species1 ,phacops caudatus1 not less than two hundred and fifty lenses have been discovered4 ,this remarkable optical instrument indicates that these creatures lived under similar conditions to those which surround the crustacea of the present day4 ,at the period of the trilobites of the ,silurian rocks1 all the animals contemporaneous with them had the organs necessary for the preservation of life in the waters4 ,next in order of time to the trilobite1 the most singular animals inhabiting those ancient seas1 whose remains have been preserved1 are the ,cephalopoda1 possessing some traces of organs which belong to vertebrated animals4 ,there are numerous arms for locomotion and prehension1 arranged in a centre round the head1 which is furnished with a pair of sharp1 horny mandibles1 embedded in powerful muscles4 ,these prehensile arms are provided with a double row of suckers1 by which the animal seized its prey4 ,of these cephalopodous animals there are many varieties1 but all of them appear to be furnished with powers of rapid locomotion1 and those with shells had an hydraulic arrangement for sinking themselves to any depth of the seas in which1 without doubt1 they reigned the tyrants4 ,passing by without notice the numerous fishes1 which appear to have exhibited a similar order of progression to the other animals1 we must proceed to the more remarkable period when the dry land first began to appear4 ,all the animals found in the strata we have mentioned are such as would inhabit the seas2 but we gradually arrive at distinct evidence of the separation of the land from the water1 and the 8green tree yielding seed0 presents itself to our attention2 not that the strata earlier than this are entirely destitute of any remains indicating vegetable growth1 but those they exhibit are such as1 in all probability1 may be referred to marine plants4 ,those plants1 however1 which are found in the carboniferous series are most of them distinguished by all the characteristics of those which grow upon the land2 we1 therefore1 in the mutilated remains of vegetation left us in our coal-formations1 read the history of our early world4 ,then the reed-like calamite bowed its hollow and fragile stems over the edges of the lakes the tree-ferns grew luxuriantly in the shelter of the hills1 and gave a wild beauty to the humid valleys2 the lepidodendrons spread themselves in mighty forests along the plains1 which they covered with their curious cones2 whilst the sigillari extended their multitudinous branches1 wreathing like serpents amongst the luxurious vegetation1 and embraced1 with their roots 7stigmari71 a most extensive space on every side4#bcd ,the seas and lakes of this period abounded with minute animals nearly allied to the coral animals1 which are now so actively engaged in the formation of islands in the tropical and southern seas4 ,during the ages which passed by without any remarkable disturbance of the surface of the earth1 the many bands of mountain limestone were formed by the ceaseless activity of these minute architects4 ,encrinites 7creatures in some respects resembling star-fish7 existed in vast numbers in the oceans of this time2 and the great variety of bivalve shells1 and those of a spiral character1 discovered in the rocks of this period1 show the waters of the newer palozoic period to have been instinct with life4 ,in the world then1 as it does now1 water acting on the dry land produced remarkable changes4 ,we have evidence of extensive districts over which the most luxuriant vegetation must have spread for ages1--from the remains of plants in every state of decay1--which we find went to form our great coal-fields4 ,these1 by some changes in the relative levels of land and water1 became covered with this fluid2 and over this mass of decaying organic matter1 sand and mud were for ages being deposited4 ,at length1 rising above the surface1 it becomes covered with vegetation1 which is1 after a period1 submerged2 the same deposition of sand and mud again takes place1 it is once more fitted for vegetable growth1 and thus1 cycle after cycle1 we see the dry land and the water changing places with each other4 ,this will be evident to every one who will carefully contemplate a section of one of the coal-fields of ,great ,britain4 ,we find a stratum of coal lying upon a bed of under clay1 and above it an extensive stratum of shale or sandstone1 probably formed by the denudation of the neighbouring hills2 and in this manner we have many strata of coal1 shale1 clay1 ironstone1 and sandstone alternating with each other2 the coal-formations of the ,south ,wales coal-field having the extraordinary thickness of #aejj feet4 ,the lowest bed of this extensive series must at one time have been exposed as the surface of the country4 ,ascending in the series1 we have now formations of a more recent character1 in which fishes of a higher order of organization1 creeping and flying saurians1 crocodiles and lizards1 tortoises1 serpents1 and frogs1 are found4 ,the lias formations 7a term corrupted from layers71 consisting of strata in which an argillaceous character prevails1 stand next in series4 ,in these we have animals preserved in a fossil state1 of a distinguishingly different character from those of the inferior strata4 ,we meet with extended beds of pentacrinites1 some inches in thickness2 and their remains are often so very complete that every part of the skeleton can be made out1 although so complicated that it cannot consist of less than #aej1jjj parts4 ,in these formations we often find the curiously beautiful remains of the ammonites1 of which a great variety have been discovered4 ,of the belemnites--animals furnished with the shell and the ink-bag of the cuttle-fish1 with which it darkened the water to hide itself from enemies1 numerous varieties have also been disentombed1 with the ink-bag so well preserved1 that the story of the remarkable fossil has been written with its own ink4 ,in addition to these we find nautili2 and sixty species of extinct fishes have been described by ,agassiz from the lias of ,lyme ,regis alone4 ,when these rocks were in the progress of formation1 there existed the ichthyosaurus1 or fish-lizard1 which appears1 in many respects1 to have resembled the crocodile of the ,nile4 ,it was a predatory creature of enormous power1 and must have been the tyrant and terror of the seas which it inhabited4 ,its alligator-like jaws1 its powerful eye1 its fish-like fins1 and turtle-like paddles1 were all formed to facilitate its progress as a destructive minister4 ,the plesiosaurus was1 if possible1 a still more extraordinary creation4 ,to the head of a lizard was united an enormously long neck1 a small and fish-like body1 and the tail of a crocodile3 it appears formed for existence in shallow waters1 so that1 when moving at the bottom1 it could lift its head above the surface for air1 or in search of its food4 ,the flora of this period must have been extensive2 and it resembled the vegetation which exists at present in ,tropical regions4 ,we pass now to a new epoch1 which is well distinguished by its animals from all that had preceded it4 ,races of reptiles still have place upon the earth1 and we have now the megalosaurian remains2 these animals possessing a strength and rapacity which would render them objects of terror as well as astonishment1 could they be restored to the world which they once ravaged4 ,an enormous bat-like creature also existed at this time--the pterodactyl--which1 in the language of ,cuvier1 was1 8undoubtedly1 the most extraordinary of all the beings of whose former existence a knowledge is granted to us1 and that which1 if seen alive1 would appear most unlike anything that exists in the present world40 8,you see before you10 says the same writer1 8an animal which1 in all points of bony structure1 from the teeth to the extremities of the nails1 presents the well-known saurian characteristics1 and of which no one can doubt that its integuments and soft parts1 its scaly armour and its organs of circulation and reproduction1 are likewise analogous4 ,but it was1 at the same time1 an animal provided with the means of flying2 and1 when stationary1 its wings were probably folded back like those of a bird1 although1 perhaps1 by the claws attached to its fingers1 it might suspend itself from the branches of trees40#bce ,from the disintegration of the older rocks have no doubt arisen those formations which are known as the oolitic series4 ,in these strata are preserved the remains of plants and animals more resembling those which now exist upon the earth2 and1 for the first time1--unless the evidence of the footsteps of birds on the new red sandstone of ,america be accepted1--we meet with the remains of the feathered tribes4 ,in these formations we discover animals belonging to the class ,mammalia1--the amphitherium and the phascolotherium1--which appear to have resembled1 in many respects1 the marsupial animals of ,new ,holland4#bcf ,the wealden formations1 which are the next in order of position1 are a series of clays and sands1 with subordinate beds of limestone1 grit1 and shale4 ,these have1 in some instances1 been formed in the sea2 but they are usually regarded as fresh-water deposits4 ,all the older rocks bear evident marks of marine origin1 unless some of the coal-measure strata may be regarded as otherwise2 but nearly all the wealden series contain the remains of land1 fresh-water1 and estuary animals1 and of land vegetables4 ,the creatures which we discover1 preserved1 to tell the history of this period1 are numerous1 and have marked peculiarities to distinguish them from those already described1 or from any now existing on the earth4 ,we find land saurians of a large kind1 and animals of all sizes2 even insects1 of which a great variety are found in the wealds4 ,the remarkable iguanodon was an animal which1 even by the cautious measurement of ,professor ,owen1 must have been at least twenty-eight feet long2 and this enormous creature was suspected1 by ,cuvier1 and has been proved by ,owen1 to have been an 8herbivorous saurian for terrestrial life40#bcg ,dr4 ,mantell calculates that no less than seventy individuals of the iguanodon of all ages have come under his notice2 and the bones of a vast number of others must have been broken up by the workmen in the few quarries of ,tilgate grit2 so that these creatures were by no means rare at the period of their existence4#bch ,the uppermost of these secondary formations is the cretaceous or chalk group1 which spreads over a large portion of south-eastern ,england1 and is met with in all parts of ,europe4 ,this chalk1 which is a carbonate of lime1 appears to have been slowly precipitated from tranquil water1 as1 according to ,sir ,henry ,de la ,beche1 organic remains are beautifully preserved in it4 ,substances of no greater solidity than common sponges retain their forms1 delicate shells remain unbroken1 fish even are frequently not flattened1 and altogether we have the appearances which justify us in concluding that1 since these organic exuvi were entombed1 they have been protected from pressure by the consolidation of the rock around them4#bci ,beneath the chalk exists what has been called1 from its colour--derived from a silicate of the protoxide of iron1--green sand1 and was1 no doubt1 formed by deposition from the same water in which the carbonate of lime was suspended1--the green sand falling to the bottom more readily from its greater specific gravity4 8,the tranquillity10 observes ,sir ,henry ,de la ,beche1 8which seems to have prevailed during this great accumulation of siliceo-calcareous matter1 whether it may have been a deposit from water1 in which it was mechanically suspended1 partly the work of living creatures1 or in a great measure chemical1 is very remarkable40#bdj ,in the chalk1 the remains of the leaves of dicotyledonous plants and fragments of wood are found more abundantly than in the earlier strata1 many of which are marked with the perforations of marine worms1 indicating that they had floated for some time in the ocean4 ,it should1 however1 be remembered1 that these are not the first indications of vegetable life1--leaves have been found in the new red sandstone2 and the flora of the coal formation must not be forgotten4 ,the manner in which silica has deposited itself on organic bodies--such as the sponges--is curious2 the whole of the organized tissue being often removed1 and flint having taken its place4 ,flints formed by such a process as this abound in the upper chalk4 ,the association of carbon and silicon1 combined with oxygen1 as we find them in the cretaceous formations1 is most interesting1 and naturally gives rise to some speculation on the relation of these two elements4 ,both carbon and silicon1 as has been already shown1 exist in several allotropic conditions2 and1 although the statements made by ,dr4 ,brown relative to the conversion of carbon into silicon are proved to be grounded on experimental error1 it is not improbable that a very intimate relation may exist between these elements4#bda ,the probability is1 that the sponge animal has the power of secreting silica to give strength to its form4 8,many species10 says ,rymer ,jones1 speaking of recent sponges1 8exhibiting the same porous structure1 have none of the elasticity of the officinal sponge--a circumstance which is due to the difference observable in the composition of their skeletons or ramified frame-work4 ,in such the living crust forms within its substance not only tenacious bands of animal matter1 but great quantities of crystallized spicula1 sometimes of a calcareous1 at others of a siliceous1 nature40 ,thus1 a frame of siliceous matter being formed by the living animal1 a deposition of the same substance is continued after death4 ,sea-urchins and star-fish1 and numerous fossil shells1 are found in these beds1 which1 however1 differ materially from the remains of the same animals found in the earlier formations4 ,a vast number of new species and genera of fish are also discovered in the chalk4 ,nearly all the animals and plants which existed up to this period are now extinct1 although they have some imperfect representatives at the present day4 ,the uppermost group1 which has been called the supercretaceous or tertiary formation1 appears in our island to have been formed during four great eras1 as we find fresh-water deposits alternating with marine ones4 ,the term eocene1 which is the first or oldest deposit2 miocene1 which is the second2 pliocene1 which is the third2 and the newer pliocene1--which is the fourth and last1 have been applied to these formations1 the names referring to the respective proportions of existing species found among their fossil shells4#bdb ,all these formations show distinct evidence of their having been deposited from still or slowly-flowing deep waters4 ,thus the eocene appears in the ,paris basin1--formed clearly at an estuary1 in which are mingled some interesting fresh-water deposits2--in the lacustrine formations in ,auvergne2 also at ,aix2 and in the north of ,italy4 ,it appears probable that1 in the formations generally termed eocene1 both fresh-water and marine deposits have been confounded1 and several formations of widely-different eras regarded as the result of one4 ,we have not yet been furnished with any distinct and clear evidence to show that the deposits of the ,paris basin1 and those of ,auvergne1 are of the same age4 ,at all events1 it is sufficient for our present purpose to know that they are the result of actions which are now as general as they were when the plastic clay of ,paris1 and its sulphate of lime1 or the ,london clay1 were slowly deposited4 ,as a general conclusion1 we may decide that1 at the eocene period1 existing continents were the sites of vast lakes1 rivers1 and estuaries1 and were inhabited by quadrupeds1 which lived upon their thickly-wooded margins4 ,many remains1 allied to those of the hippopotamus1 have been found in the subsidences of this period4 ,examples of the miocene or middle tertiary era are to be found in ,western ,france1 over the whole of the great valley of ,switzerland1 and the valley of the ,danube4 ,in these deposits we find the bones of the rhinoceros1 elephant1 hippopotamus1 and the dinotherium1 an extinct animal1 possessing many very distinguishing features4#bdc ,the pliocene period has been termed the age of elephants1 and is most remarkable for the great mastodons and gigantic elks1 with other animals not very unlike those which are contemporaneous with man4 ,in the superficial layers of the earth1 the diluvium1 alluvium1 peat and vegetable soil1 we have a continuation of the history of the mutations of our globe and of its inhabitants1 which has been here so briefly sketched4 ,they bring us up to the period when man appeared in the world1 since whose creation it is evident no very extensive change has been produced upon the surface4 ,we have viewed the phenomena of each great epoch1 marked as they are by new creations of organized beings1 and it would appear as if1 through the whole series1 from the primary rocks up to the modern alluvial deposits1 a progressive improvement of the earth's surface had been effected1 to fit it at last for the abode of the human race4 ,thus have we preserved for us1 in a natural manner1 evidences which1 if we read them aright1 must convince us that the laws by which creation has ever been regulated are as constant and unvarying as the ,eternal mind by which they are decreed4 ,our earth1 we find1 by the records preserved in the foundation-stones of her mountains1 has existed through countless ages1 and through them all exhibited the same active energies that prevail at the present moment4 ,by precisely similar influences to those now in operation1 have rocks been formed1 which1 under like agencies1 have been covered with vegetation1 and sported over by1 to us1 strange varieties of animal life4 ,every plant that has grown upon the earliest rocks which presented their faces to the life-giving sun1 has had its influence on the subsequent changes of our planet4 ,each trilobite1 each saurian1 and every one of the mammalia which exist in the fossil state1 have been small laboratories in which the great work of eternal change has been carried forward1 and1 under the compulsion of the strong laws of creation1 they have been made ministers to the great end of forming a world which might be fitting for the presence of a creature endued with a spark taken from the celestial flame of intellectual life4 ,for a few moments we will return to a consideration of the operations at present exhibiting their phenomena1 and examine what bearing they have upon our knowledge of geological formations4 ,during periods of immense1 but unknown1 duration1 the ocean and the dry land are seen to have changed their places4 ,enormous deposits1 formed at the bottom of the sea1 are lifted by some mechanical1 probably volcanic1 force1 above the waters1 and the land1 like the ocean surrounding it1 teems with life4 ,this state of things lasts for ages2 but the time arrives when the ocean again floods the land1 and a new state of things1 over a particular district1 has a beginning4 ,it must not be imagined that the changes which we have spoken of1 as if they were the result of slow decay and gradual deposit1 were effected without occasional violent convulsions4 ,many of the strata which were evidently deposited at the bottom of the sea1 and1 of course1 as horizontal beds1 are now found nearly vertical4 ,we have evidence of strata of immense thickness having been subjected to forces that have twisted and contorted them in a most remarkable manner4 ,masses of solid rock1 many thousand feet deep1 are frequently bent and fractured throughout their whole extent4 ,mountains have been upheaved by internal force1 and immense districts have suddenly sunk far below their usual level4 ,by the expansive force due to that temperature which must be required to melt basaltic and trap rocks1 the whole of the superficial crust of a country has been heaved to a great height1 immense fissures have been formed by the breaking of the mass1 and the melted matter has been forced through the opening1 and overflowed extensive districts1 or volcanoes have been formed1 and wide areas have been buried under the ashes ejected from them4 ,with the cause of these convulsions we are at present unacquainted4 ,we have evidence of the extent to which these forces may be exerted1 in the catastrophes which have occurred within historical times1 and which have happened even in our own day4 ,herculaneum and ,pompeii1 buried under the lava and ashes of ,vesuvius1 in an hour when the inhabitants of these cities were unprepared for such a fearful visitation1--the frightful earthquakes which have1 from time to time1 occurred in ,south ,america--are evidences of the existence of hidden forces which shake the firm-set earth4 ,similar ravaging catastrophes may have often occurred1 and1 involving cataclysms1 swept the surface to produce the changes we detect over every part of the earth1 compared with which the earthquakes and floods of history are but trivial things4 ,evidence has been adduced1 to show that the mountains of the ,old ,world may have approached in height the highest of the ,andes or ,himalayas1 and these have not been destroyed by any sudden effect1 but by the slow disintegrating action of the elements4#bdd ,all these phenomena are now in progress3 the winds and the rains wear the faces of the exposed rock2 their dbris1 mixed with decayed vegetable and animal matter1 are washed off from the surface1 and borne away by the rivers1 to be deposited in the seas4 ,thus it is that the great delta of the ,ganges is formed1 and that a continual increase of matter is going on at the mouths of rivers4 ,the ,amazon1 the ,mississippi1 and other great rivers1 bear into the ocean1 daily1 thousands of tons of matter from the surface of the earth4#bde ,this is1 of course1 deposited at the bottom of the sea1 and it must1 in the process of time1 alter the relative levels of the ocean and the land4 ,islands have been lifted by volcanic power from the bottom of the sea1 and many districts in ,south ,america have been depressed by the same causes4 ,changes as extensive have been1 in all probability1 effected by forces 8equally or more powerful1 but acting with less irregularity1 and so distributed over time as to produce none of those interregnums of chaotic anarchy which we are apt to think 7perhaps erroneously7 great disfigurements of an order so beautiful and harmonious as that of nature40#bdf ,these forces are1 without doubt1 even now in action4 ,had it not been for these convulsive disturbances of the surface1 the earth would have presented an almost uniform plain1 and it would have been ill-adapted for the abode of man4 ,the hills raised by the disturbances of nature1 and the valleys worn by the storms of ages1 minister especially to his wants1 and afford him the means of enjoyment which he could not possess had the surface been otherwise formed4 ,the 8iced mountain tops10 condensing the clouds which pass over them1 send down healthful streams to the valleys1 and supply the springs of the earth1 thus securing the fertility and salubrity of the distant plains4 ,the severities of climate are mitigated by these conditions1 and both the people of the tropics and those dwelling near the poles are equally benefited by them4 ,gravitation1 cohesion1 motion1 chemical force1 heat1 and electricity1 must1 from that hypothetical time when the earth floated a cloud of nebulous vapour1 in a state of gradual condensation up to the present moment1 have been exercising their powers1 and regulating the mutations of matter4 ,when the dry land was beneath the waters1 and when darkness was upon the face of the deep1 the same great operations as those which are now in progress in the depths of the ,atlantic1 or in the still waters of our inland lakes1 were in full activity4 ,at length the dry land appears2 and--mystery of mysteries--it soon becomes teeming with life in all the forms of vegetable and animal beauty1 under the aspect of the beams of a glorious sun4 ,geology teaches us to regard our position upon the earth as one far in advance of all former creations4 ,it bids us look back through the enormous vista of time1 and see1 shining still in the remotest distance1 the light which exposes to our vision many of nature's holy wonders4 ,the elements which now make up this strangely beautiful fabric of muscle1 nerves1 and bone1 have passed through many ordeals1 ere yet it became fashioned to hold the human soul4 ,no grain of matter has been added to the planet1 since it was weighed in a balance1 and poised with other worlds4 ,no grain of matter can be removed from it4 ,but in virtue of those forces which seem to originate in the sun1 8the soul of the great earth10 a succession of new forms has been produced1 as the old things have passed away4 ,under the forces we have been considering1 acting as so many contending armies1 matter passes from one condition to another1 and what is now a living and a breathing creature1 or a delicate and sweetly-scented flower1 has been a portion of the amorphous mass which once lay in the darkness of the deep ocean1 and it will again1 in the progress of time1 pass into that condition where no evidences of organization can be found1--again1 perhaps1 to arise clothed with more exalted powers than even man enjoys4 ,when man places himself in contrast with the ,intelligences beyond him1 he feels his weakness2 and the extent of power which he can discover at work1 guided by a mysterious law1 is such1 that he is dwarfed by its immensity4 ,but looking on the past1 surveying the progress of matter through the inorganic forms up to the higher organizations1 until at length man stands revealed as the chief figure in the foreground of the picture1 the monarch of a world on which such elaborate care has been bestowed1 and the absolute ruler of all things around him1 he rises like a giant in the conscious strength of his far-searching mind4 ,that so great1 so noble a being1 should suffer himself to be degraded by the sensualities of life to a level with the creeping things1 upon which he has the power to tread1 is a lamentable spectacle1 over which angels must weep4 ,the curious connection between the superstitions of races1 the traditionary tales of remote tribes1 and the developments of the truths of science1 are often of a very marked character1 and they cannot but be regarded as instructive4 ,in the wonders of 8olden time0 fiction has ever delighted2 and a thousand pictures have been produced of a period when beings lived and breathed upon the earth which have no existence now4 ,hydras1 harpies1 and sea-monsters1 figure in the myths of antiquity4 ,in the mythology of the northern races of ,europe we have fiery flying dragons1 and ,poetry has placed these as the guardians of the 8hoarded spirit0 and protectors of the enchanted gold4 ,through the whole of the romance period of ,european literature1 nothing figures but serpents1 8white and red10 toiling and fighting underground1--thus producing earthquakes1 as in the story of ,merlin and the building of ,stonehenge4 ,flying monsters1 griffins and others1 which now live only in the meaningless embellishments of heraldry1 appear to have been conceived by the earlier races of men as the representatives of power4 ,curious is it1 too1 to find the same class of ideas prevailing in the ,east4 ,the monster dragons of the ,chinese1 blazoned on their standards and ornamenting their temples2--the ,buddaical superstition that the world is supported on a vast elephant1 which stands on the back of a tortoise1 which again rests on a serpent1 whose movements produce earthquakes and violent convulsions2--the rude decorations also of the temples of the ,aztecs1 which have been so recently restored to our knowledge by the adventurous travellers of ,central ,america1--all give expression to the same mythological idea4 ,do not these indicate a faint and shadowy knowledge of a previous state of organic existence8 ,the process of communion between man of the present1 and the creations of a former world1 we know not2 it is mysterious1 and for ever lost to us4 ,but even the most ignorant and uncultivated races of mankind have figured for themselves the images of creatures which1 whilst they do really bear some resemblance to things which have for ever passed away1 do not1 in the remotest degree1 partake of any of the peculiarities of existing creations4 ,the ichthyosaurus1 and the plesiosaurus1 and the pterodactylus1 are preserved in the rude images of harpies1 of dragons1 and of griffins2 and1 although the idea of an elephant standing on the back of a tortoise was often laughed at as an absurdity1 ,captain ,cautley and ,dr4 ,falconer at length discovered in the hills of ,asia the remains of a tortoise in a fossil state of such a size that an elephant could easily have performed the feat4#bdg ,of the ammonites1 we have more exact evidence2 they were observed by our forefathers1 and called by them snake-stones4 ,according to the legends of ,catholic saints they were considered as possessing a sacred character3-- 8,of these and snakes1 each one ,was changed into a coil of stone ,when holy ,hilda prayed40 ,and in addition to this petrifying process1 one of decapitation is said to have been effected2 hence the reason why these snake-stones have no heads4 ,we also find1 in the northern districts of our island1 that the name of 8,st4 ,cuthbert's beads0 is applied to the fossil remains of encrinites4 ,thus we learn that1 to a great extent1 fiction is dependent upon truth for its creations2 and we see that when we come to investigate any wide-spread popular superstition1 although much distorted by the medium of error through which it has passed1 it is frequently founded upon some fragmentary truth4 ,there are floating in the minds of men certain ideas which are not the result of any associations drawn from things around2 we reckon them amongst the mysteries of our being4 ,may they not be the truths of a former world1 of which we receive the dim outshadowing in the present1 like the faint lights of a distant ,pharos1 seen through the mists of the wide ocean8 ,man treads upon the wreck of antiquity4 ,in times which are so long past1 that the years between them cannot be numbered by the aids of our science1 geology teaches us that forms of life existed perfectly fitted for the conditions of the period4 ,these performed their offices in the great work2 they passed away1 and others succeeded to carry on the process of building a world for man4 ,the past preaches to the present1 and from its marvellous discourses we venture to infer something of the yet unveiled future4 ,the forces which have worked still labour3 the phenomena which they have produced will be repeated4 ,ages on ages slowly pass away1 ,and nature marks their progress by decay4 ,the plant which decks the mountain with its bloom1 ,finds in the earth1 ere long1 a damp dark tomb3 ,and man1 earth's monarch1 howe'er great and brave-- ,toils on--to find at last a silent grave4 ,the chosen labours of his teeming mind ,fade by the light1 and crumble 'neath the wind2 ,and e'en the hills1 whose tops appear to shroud ,their granite peaks deep in the vapoury cloud1 ,worn by tempests--wasted by the rains1 ,sink slowly down to fill wide ocean's plains4 ,the ocean's breast new lands again display1 ,and life and beauty drink the light of day3 ,the powers which work at great creation's wheel1 ,will from the wrecks of matter still reveal ,new forms of wondrous beauty--which will rise ,pure as the flame of love's young sacrifice1 ,beaming with all the pristine hues of youth1 ,robed by the day1 and crowned by holy truth4 ,,footnotes3 #bca ,preliminary ,discourse2 ,sir ,j4 ,f4 ,w4 ,herschel4 ,lardner's ,cabinet ,cyclopdia4 #bcb ,geological ,researches2 by ,sir ,henry ,de la ,beche1 ,c4,b4 7,degradation of ,mountains1 p4 #afg47 ,geological ,manual1 p4 #ahd4 ,principles of ,geology2 by ,sir ,charles ,lyell1 #gth ,edition1 p4 #aej1 #fhf4 ,on the ,denudation of ,south ,wales1 and the adjacent countries of ,england2 by ,professor ,andrew ,ramsay2 ,memoirs of the ,geological ,survey and ,museum of ,practical ,geology1 vol4 i4 p4 #big4 #bcc ,fownes1 ,on the ,existence of ,phosphoric ,acid in ,rocks of ,igneous ,origin2 ,phil4 ,trans4 #ahdd1 p4 #ec4 ,nesbitt1 ,quarterly ,journal of the ,chemical ,society4 #bcd ,on the ,vegetation of the ,carboniferous ,period as compared with that of the present day2 ,on some peculiarities in the structure of ,stigmaria2 ,remarks on the ,structure and ,affinities of some ,lepidostrobi3 by ,dr4 ,hooker2 ,memoirs of the ,geological ,survey1 c41 vol4 ii4 pp4 #chg1 #dca1 #ddj4 #bce ,see ,owen1 ,quarterly ,journal of the ,geological ,society1 ,no4 #f1 p4 #if4 ,dr4 ,buckland1 ,geological ,transactions1 vol4 iii4 p4 #bbj4 ,the ,wonders of ,geology3 by ,dr4 ,mantell1 vol4 ii4 p4 #dic4 #bcf ,report on ,british ,fossil ,mammalia3 by ,richard ,owen1 ,esq41 ,f4,r4,s42 ,british ,association ,reports1 vols4 xi4 xii4 #bcg ,notice on the ,iguanodon1 a newly discovered fossil reptile from the sandstone of ,tilgate ,forest1 in ,sussex3 by ,gideon ,mantell1 ,esq1 ,f4,r4,s41 c42 ,philosophical ,transactions1 vol4 cxv4 p4 #agi4 ,on the ,structure of ,teeth1 c42 by ,professor ,owen4 #bch ,dr4 ,mantell1 ,wonders of ,geology4 ,geology of the ,south-east of ,england4 #bci ,geological ,researches2 ,geological ,manual2 by ,sir ,henry ,thos4 ,de la ,beche1 ,c4,b41 c4 #bdj ,ibid4 #bda ,experimental ,researches on the production of ,silicon from ,paracyanogen3 by ,samuel ,brown1 ,m4,d42 ,transactions of the ,royal ,society of ,edinburgh1 vol4 xv4 p4 #bbi4 ,experiments on the alleged conversion of ,carbon into ,silicon3 by ,r4 ,h4 ,brett1 ,ph4,d41 and ,j4 ,denham ,smith1 ,esq42 ,philosophical ,magazine1 vol4 xix4 p4 #bie1 ,new ,series4 ,see also ,dr4 ,brown's reply to the above1 ibid1 p4 #chh4 #bdb ,geology1 ,introductory1 ,descriptive1 and ,practical3 by ,prof4 ,ansted1 vol4 ii4 p4 #bb4 #bdc ,the ,wonders of ,geology3 by ,dr4 ,mantell1 vol4 i4 p4 #afb4 ,bridgewater ,treatise3 by ,dr4 ,buckland4 ,dr4 ,j4 ,j4 ,kemp1 and ,dr4 ,a4 ,v4 ,klipstein1 ,on the ,dinotherium2 ,darmstadt1 #ahcf4 ,cuvier and ,de ,blainville have also carefully described the fossil remains of this animal4 #bdd ,see ,professor ,ramsay's memoir ,on ,denudation3 ,memoirs of the ,geological ,survey of ,great ,britain4 #bde 8,the distances to which river water1 more or less charged with detritus1 would flow over sea-water1 will depend upon a variety of obvious circumstances4 ,captain ,sabine found discoloured water1 supposed to be that of the ,amazons1 three hundred miles distant in the ocean from the embouchure of that river4 ,it was about #abf feet deep4 ,its specific gravity was #ajbjd1 and the specific gravity of the sea-water #ajbfb4 ,this appears to be the greatest distance from land at which river water has been detected on the surface of the ocean4 ,if rivers1 containing mechanically suspended detritus1 flowed over sea-water in lines which1 in general terms1 might be called straight1 the deposit of transported matter which they carried out would also be in straight lines4 ,if1 however1 they be turned aside by an ocean current1 as was the case with that observed by ,captain ,sabine1 the detritus would be thrown1 and cover an area corresponding in a great degree with the sweep which the river has been compelled to make out of the course1 that its impulse1 when discharged from its embouchure1 might lead it to take3 supposing the velocity with which this river-water was moving has been correctly estimated at about three miles per hour1 it is not a little curious to consider that the agitation and resistance of its particles should be sufficient to keep finely comminuted solid matter mechanically suspended1 so that it would not be disposed freely to part with it1 except at its junction with the sea-water over which it flows1 and where1 from friction1 it is sufficiently retarded4 ,so that a river1 if it can preserve a given amount of velocity flowing over the sea1 may deposit no very large amount of mechanically suspended detritus in its course from the embouchure1 where it is ultimately stopped4 ,still1 however1 though the deposit may not be so abundant as at first sight would appear probable1 the constant accumulation of matter1 however inconsiderable at any given time1 must produce an appreciable effect during the lapse of ages40--,sir ,henry ,de la ,beche's ,geological ,researches1 p4 #gb4 #bdf ,sir ,j4 ,f4 ,w4 ,herschel3 ,preliminary ,treatise4 #bdg ,fauna ,antiqua ,sivalensis4 ,being the ,fossil ,zoology of the ,sewalik ,hills in the ,north of ,india3 by ,hugh ,falconer and ,proby ,t4 ,cautley4 #ahdd4 ,,chapter ,,xiv4 ,,phenomena ,,of ,,vegetable ,,life4 ,psychology of ,flowers--,progress of ,matter towards ,organization--,vital ,force--,spontaneous ,generation--,the ,vegetable ,cell--,simplest ,development of ,organization--,the ,crystal and the ,cell--,primitive ,germ--,progress of ,vegetation--,influence of ,light--,morphology--,germination--,prod uction of ,woody ,fibre--,leaves--,chlorophylle--,decompo sition of ,carbonic ,acid--,influence of ,light1 ,heat1 and ,actinism on the ,phenomena of ,vegetable ,life--,flowers and ,fruits--,etiolation--,changes in the ,sun's ,rays with the ,seasons--,distribution of ,plants--,electrical and ,combined ,physical ,powers ,the variety of beautiful forms which cover the surface of this sphere1 serve1 beyond the physical purposes to which we have already alluded1 to influence the mind1 and give character to the inhabitants of every locality4 ,there are men who appear to be dead to the mild influences of flowers2 but these sweet blossoms--the stars of our earth--exert a power as diffusive as their pervading odours4 ,the poet tells us of a man to whom ,the primrose on the river's brim ,a yellow primrose was to him1 ,and it was nothing more4 ,but it was something more4 ,he1 perhaps1 attended not to the eloquent teaching of its pure1 pale leaves3 he might not have been conscious of the mysterious singing of that lowly flower3 he might1 perchance1 have crushed it beneath his rude foot rather than quaff the draught of wisdom which it secreted in its cell2 but the flower still ministered to that mere sensualist1 and in its strange1 tongueless manner1 reproved his passions1 and kept him 8a wiser and a better man18 than if it had pleased ,god to have left the world without the lovely primrose4 ,the psychology of flowers has found many students--than whom not one read them more deeply than that mild spirit who sang of the ,sensitive ,plant1 and in wondrous music foreshadowed his own melancholy fate4#bdh ,that martyr to sensibility1 ,keats1 who longed to feel the flowers growing above him1 drew the strong inspiration of his volant muse from those delicate creations which exhibit the passage of inorganic matter into life2 and other poets will have their sensibilities awakened by the sthetics of flowers1 and find a mirror of truth in the crystal dew-drop which clings so lovingly to the purple violet1 and draws fresh beauties from its coloured petals4 ,if we examine carefully all the conditions of matter which we have made the subject of our studies1 we cannot but perceive how gradual is the progress of the involved action of the physical forces1 as we advance from the molecule--the mere particle of matter--up to the organic combination4 ,at first we detect only the action of cohesion in forming the rude mass2 then we have the influence of the crystallogenic powers giving a remarkable regularity to bodies2 we next discover the influences of heat and electrical force in determining condition1 and of chemical action as controlled by them4 ,yet1 still we have a body without organization4 ,light exerts its mysterious powers1 and the same elements assume an organized form2 and1 in addition to the recognized agencies1 we dimly perceive others on which vitality evidently depends4 ,these empyreal influences become more and more complicated to us3 ascending in the scale1 they rise beyond our science2 and1 at length1 we find them guiding the power of intelligence1 while instinct and reason are exhibited in immediate dependence upon them4 ,let it not be imagined that this view has any tendency to materialism4 ,the vital energy is regarded as a spiritualization1 and reason as a divine emanation2 but they are connected with materialities1 on which they act1 and by which they are themselves controlled4 ,the organic combinations1 and the physical powers by which these unions of matter are effected and retained1 have a direct action over that ethereality which is life1 and the powers of life again control these more material forces4 ,the spirit1 in whatever state1 when connected with matter1 is1 like ,prometheus chained to his rock1 in a constant struggle to escape from its shackles1 and assert the full power of its divine strength4 ,we have seen variety enough in the substances which make up the inorganic part of creation2 but infinitely more varied are the forms of organization4 ,in the vegetable world which is immediately around us1 from the green slime of our marshes to the lustrous flowers of our gardens and the lordly trees of our forests1 what an extraordinary diversity of form is apparent6 ,from the infusoria of an hour1 to the gigantic elephant roaming in his greatness in the forests of ,siam--the noble lion of the caves of ,senegal--the mighty condor of the ,andes--and onward to man1 the monarch of them all1 how vast are the differences1 and yet how complete are they in their respective conditions6 ,in the creation we have examined1 we have had conclusive evidence1 that from the combination of atoms every peculiar form has been produced4 ,in the creation we are about to examine1 we shall discover that all the immense diversity of form1 of colour1 and condition which is spread over the world in the vegetable and animal kingdoms1 results from the combination of cells4 ,the atom of inorganic nature becomes a cell in organic creation4 ,this cell must be regarded as the compound radical of the chemist1 and by decomposing it1 we destroy the essential element of organization4 ,with the mysterious process by which the atom is converted into a cell1 or a compound radical1 we are unacquainted2 but we must regard the cell as the organic atom4 ,it is in vain that the chemist or the physiologist attempts to examine this change of the inorganic elements to an organized state2 it is one of the mysteries of creation1 which is to be1 in all probability1 hid from our eyes1 until this 8mortal coil0 is shaken off1 and we enjoy the full powers of that intelligence which we are promised we shall enjoy in an immortal state4 ,again and again has the attention of men been attracted to the generatio quivoca2 they have sometimes thought they have discovered a generatio primitiva or spontanea2 but a more careful examination of these organisms has shown that an embryo existed--a real germination has taken place4 ,count ,rumford#bdi stated that threads of silk and wool had the power of decomposing carbonic acid in water in the sunshine2 and hence some have referred organization to a mere chemical change produced by luminous excitation2 and we have heard of animal life resulting from pounded siliceous matter4 ,all such statements must be regarded as evidences of imperfect investigation4 ,dr4 ,carus1 alluding to the experiments of ,gruithuisen1 ,priestley1 and ,ingenhousz1#bej says3--8,these show1 more than any other experiments1 that1 in the purest water1 under the influence of air1 light1 and heat1 beings are formed1 which1 oscillating as it were between the animal and the plant1 exhibit the primitive germs of both kingdoms40#bea ,treviranus#beb repeated1 and appeared to confirm these results2 but in these experiments we have no evidence that the germ did not previously exist in the spring-water which was employed4 ,some have regarded the cell as a crystal2 they see the crystal forming1 by the accumulation of atoms1 into a fixed form1 under the influence of an 8inner life20 and1 advancing but a step1 they regard the cell as the result of an increased exercise of the physical influences4#bec ,we have referred crystalline form to certain magnetic conditions2 and it is evident that the atomic cell is influenced by similar forces2 but if we place a crystal in its natural fluid1 though it increases in size1 it never alters in form3 whereas1 if we examine a cell in its natural position1 it gives indications of motion1 it produces other cells1 and we have a development of organs which are in no respect the same in form as the original4 ,from a vesicle floating invisible to the unaided human sense in its womb of fluid1 is produced a plant possessing strange powers1 or an animal gifted with volition4 ,the idea1 that two kinds of polarity--light on one side1 and gravitation on the other--produce the two peculiar developments of roots and branches1 can only be regarded as one of those fanciful analogies which prove more imagination than philosophy4#bed ,the conditions are1 however1 most curious2 they deserve very attentive study2 but in examining the phenomena1 the safest course is to allow the effects as they arise to interpret to us1 and not admit the love of hypothesis to lead us into bewildering analogies2 or uncertain phenomena to betray us to hasty inferences4 ,it is of this evil that ,bacon speaks1 in his 8,advancement of ,learning40 ,he says3-- 8,the root of this error1 as of all others1 is this1 that men1 in their contemplations of nature1 are accustomed to make too timely a departure1 and too remote a recess from experience and particulars1 and have yielded and resigned themselves over to the fumes of their own fancies and popular argumentations40 ,without venturing1 therefore1 to speculate on the origin of the primitive cell1 or unit of organic life1 which involves the problem of the metamorphosis of a rude mass--the primitive transformation of the rudimentary atoms into organic form1--we must admit that the highly organized plant or animal is but an aggregation of cells2 their arrangement being dependent upon certain properties peculiar to them1 and the exercise of forces such as we have been studying1--all of which appear to act externally to the plant or animal itself4 ,experiments have been brought forward1 in which it appeared that1 after all organization which could by any possibility have existed1 had been destroyed by the action of fire1 solutions of flint and metallic salts1 have1 under the influence of electric currents1 exhibited signs of organic formations1 and that1 indeed1 insects--a species of acari--have been developed in them4 ,the experiments were said to have been made with care1 and many precautions taken to shut out all chances of any error1 but not all the precautions required in a matter of such exceeding delicacy2 and we are bound not to receive the evidence afforded as the true expression of a fact without much further investigation4 ,all experience1--setting aside the experiment named1--is against the supposition that pounded or dissolved flint could by any artificial means be awakened into life4 ,ova may have been conveyed into the vessels which contained the solutions under experiment2 and in due time1 although possibly quickened by electric excitation1 the animals--the most common of insects--came into existence4#bee ,the rapid growth of conferv upon water has often been brought forward as evidence of a spontaneous generation1 or the conversion of inorganic elements into organic forms2 but it has been most satisfactorily proved that the germ must be present1 otherwise no evidence of anything like organization will be developed4 ,all the conditions required for the production of vegetable life appear to show1 that it is quite impossible for any kind of plant1 even the very lowest in the scale1 to be formed in any other way than from an embryo in which are contained the elements necessary for it1 and the arrangements required for the various processes which are connected with its vitality4 ,the earth is now covered with vegetable life1 but there must have existed a time when 8darkness was upon the face of the deep10 and organization had not yet commenced tracing its lovely net-work of cells upon the bare surface of the ocean-buried rock4 ,at length the mystery of organic creation began3 into this science dares not penetrate1 but it is privileged to begin its search a little beyond this point1 and we are enabled to trace the progress of organic development through a chain of interesting results which are constantly recurring4 ,if we take some water1 rising from a subterranean spring1 and expose it to sunshine1 we shall see1 after a few days1 a curious formation of bubbles1 and the gradual accumulation of green matter4 ,at first we cannot detect any marks of organization--it appears a slimy cloud of an irregular and undetermined form4 ,it slowly aggregates1 and forms a sort of mat over the surface1 which at the same time assumes a darker green colour4 ,careful examination will now show the original corpuscles involved in a net-work formed by slender threads1 which are tubes of circulation1 and may be traced from small points which we must regard as the compound atom1 the vegetable unit4 ,we must not forget1 here1 that we have to deal with four chemical elements1--oxygen1 hydrogen1 carbon1 and nitrogen1 which compose the world of organized forms1 and that the water affords us the two first as its constituents1 gives us carbon in the form of carbonic acid dissolved in it1 and that nitrogen is in the air surrounding it1 and frequently mixed with it also4 ,under the influence of sunshine1 we have now seen these elements uniting into a mysterious bond1 and the result is the formation of a cellular tissue1 which possesses many of the functions of the noblest specimens of vegetable growth4 ,but let us examine the progress4 ,the bare surface of a rock rises above the waters covered over with this green slime1 a mere veil of delicate net-work1 which1 drying off1 leaves no perceptible trace behind it2 but the basis of a mighty growth is there1 and under solar influence1 in the process of time1 other changes occur4 ,after a period1 if we examine the rock1 we shall find upon its face little coloured cups or lines with small hard discs4 ,these1 at first sight1 would not be taken for plants1 but on close examination they will be found to be lichens4 ,these minute vegetables shed their seed and die1 and from their own remains a more numerous crop springs into life4 ,after a few of these changes1 a sufficient depth of soil is formed1 upon which mosses begin to develope themselves1 and give to the stone a second time a faint tint of green1 a mere film still1 but indicating the presence of a beautiful class of plants1 which1 under the microscope1 exhibit in their leaves and flowers many points of singular elegance4 ,these mosses1 like the lichens1 decaying1 increase the film of soil1 and others of a larger growth supply their places1 and run themselves the same round of growth and decay4 ,by and by1 funguses of various kinds mingle their little globes and umbrella-like forms4 ,season after season plants1 perish and add to the soil1 which is at the same time increased in depth by the disintegration of the rock over which it is laid1 the cohesion of particles being broken up by the operations of vegetable life4 ,the minute seeds of the ferns floating on the breeze1 now find a sufficient depth of earth for germination1 and their beautiful fronds1 eventually1 wave in loveliness to the passing winds4 ,vegetable forms of a higher and a higher order gradually succeed each other1 each series perishing in due season1 and giving to the soil additional elements for the growth of plants of their own species or those of others4 ,flowering herbs find a genial home on the once bare rock2 and the primrose pale1 the purple foxglove1 or the gaudy poppy1 open their flowers to the joy of light4 ,the shrub1 with its hardy roots interlaced through the soil1 and binding the very stones1 grows rich in its bright greenery4 ,eventually the tree springs from the soil1 and where once the tempest beat on the bare cold rock1 is now the lordly and branching monarch of the forest1 with its thousand leaves1 affording shelter from the storm for bird and beast4 ,such are the conditions which prevail throughout nature in the progress of vegetable growth2 the green matter gathering on a pond1 the mildew accumulating on a shaded wall1 being the commencement of a process which is to end in the development of the giant trees of the forest1 and the beautifully tinted flower of nature's most chosen spot4 ,we must now consider closely the phenomena connected with the growth of an individual plant1 which will illustrate the operation of physical influences throughout the vegetable world4 ,the process by which the embryo1 secured in the seed1 is developed1 is our first inquiry4 ,a seed is a highly carbonized body1 consisting of integuments and embryo3 between these1 in most seeds1 lies a substance called the albumen1 or perisperm4 ,the embryo contains the elements of the future plant--the cotyledons1 the plumule1 and the radicle2 the former developing into stalk and leaves1 the latter into roots4 ,this embryo hides the living principle1 for the development of which it is necessary that the starch and gluten undergo a chemical change1 and that an elevation of temperature is produced4 ,the vital power is dormant--it sleeps--in the seed until the proper conditions are produced4 ,it has been proved1 that the powers of maintaining life in the seed are very great2 excessive cold1 sufficiently intense to freeze mercury1 will not kill seed1 and they resist a comparatively high temperature4 ,it is probable that heat only destroys seeds by drying them too completely4 ,the temperature at which seeds germinate is exceedingly varied1--those belonging to our own clime will germinate when the thermometer rises above #dj ,f41 but the seeds of tropical plants demand that a temperature of from #gj to #hd1 or even to #ij1 be steadily applied to them4 ,in some cases it has been found that even boiling the seeds has been advantageous to the future process of germination in the soil4 ,but let us take the seed of some ordinary plant1 and trace its progress4 ,an apparently dead grain is placed in the soil4 ,if the temperature is a few degrees above the freezing point1 and the soil holds a due quantity of water1 the integument of the seed imbibes moisture and swells2 the tissue is softened1 and the first effort of vital force begins4 ,the seed has now the power of decomposing water1 the oxygen combines with some of the carbon of the seed1 and is expelled as carbonic acid4 ,saussure's experiments prove this4 ,the air above the soil in which a horse-bean was placed to germinate1 gave1 before the experiment1 nitrogen #bajbf1 and oxygen #efbi1 and after germination1 nitrogen #bjida1 oxygen #ddch1 and carbonic acid #aabg4 ,this part of the process is but little removed from the merely chemical changes which we have already considered4 ,we find the starch of the seed changed into gum and sugar1 which affords nutritive food for the developing embryo4 ,the seed now lengthens downwards by the radicle1 and upwards by the cotyledons1 which1 as they rise above the earth1 acquire a green colour4 ,here the first stage of vegetable life ends1 the chemically exciting process is at an end1 and a new stimulus is required to continue in full activity the vital powers4 ,carbonic acid is no longer given off4 ,the cotyledons1 which are two opposite roundish leaves1 act as the lungs2 by them carbonic acid taken from the atmosphere is absorbed and carried by a circulating process1 now in full activity1 through the young plant4 ,the carbonic acid1 a compound of carbon and oxygen1 is decomposed2 it is deprived of its carbon1 which is retained by the plant1 and oxygen is exhaled4 ,the plant at this period is little more than an arrangement of cellular tissue1 a very slight development of vascular and fibrous tissue appearing as a cylinder lying in the centre of the sheath4 ,at this point1 however1 we begin more distinctly to trace the operations of the new power2 the impulses of life are strikingly evident4 ,the young root is now lengthening1 and absorbing from the moisture in the soil1 which always contains some soluble salts1 a portion of its nutriment1 which is impelled upwards by a force--probably capillary attraction and endosmose action combined--to the point from which the plumule springs4 ,capillary force raises the fluids through the tubes in the stalk1 and conveys them to the veins in the leaves1 while the endosmose force diffuses them through the vegetable tissues4 ,the plumule first ascends as a little twig1 and1 at the same time1 by exerting a more energetic action on the carbonic acid than the cotyledons have done1 the carbon retained by them being only so much as is necessary to form chlorophylle1 or the green colouring matter of leaves1 some wood is deposited in the centre of the radicle4 ,from this time the process of lignification goes on through all the fabric1--the increase1 and indeed the life1 of the plant depending upon the development of a true leaf from the plumule4 ,it must not be imagined that the process consists1 in the first place1 of a mere oxidation of the carbon in the seed1--a slow combustion by which the spark of life is to be kindled2--the hydrogen of the water plays an important part1 and1 combining also with the carbon1 forms necessary compounds1 and by a secondary process gives rise again to water by combination with oxygen in the cells of the germinating grain4 ,nor must we regard the second class of phenomena as mere mechanical processes for decomposing carbonic acid1 but the result of the combined influences of all the physical powers and life superadded4 ,this elongating little twig1 the plumule1 at length unfolds itself1 and the branch is metamorphosed into a leaf4 ,the leaf arates the sap it receives1 effects the decomposition of the carbonic acid1 the water1 and in all probability the ammonia which it derives from the air1 and thus returns to the pores1 which communicate with the pneumatic arrangements of the plant1 the necessary secretions for the formation of bark1 wood1 and the various proximate principles which it contains4 ,after the first formation of a leaf1 others successively appear1 all constructed alike1 and performing similar functions4 ,the leaf is the principal organ to the tree2 and1 indeed1 ,linnus divined1 and ,goethe demonstrated1 the beautiful fact1 that the tree was developed from this curiously-formed organ4 8,keeping in view10 says the poet-philosopher1 8the observations that have been made1 there will be no difficulty in discovering the leaf in the seed-vessel1 notwithstanding the variable structure of that part and its peculiar combinations4 ,thus the pod is a leaf which is folded up and grown together at its edges1 and the capsules consist of several leaves grown together1 and the compound fruit is composed of several leaves united round a common centre1 their sides being opened so as to form a communication between them1 and their edges adhering together4 ,this is obvious from capsules which1 when ripe1 split asunder1 at which time each portion is a separate pod4 ,it is also shown by different species of one genus1 in which modifications exist of the principle on which their fruit is formed2 for instance1 the capsule of nigella orientalis consists of pods assembled round a centre1 and partially united2 in nigella damascena their union is complete40#bef ,professor ,lindley thus explains the same view3--8,every flower1 with its peduncle and bracteol1 being the development of a flower-bud1 and flower-buds being altogether analogous to leaf-buds1 it follows as a corollary that every flower1 with its peduncle and bracteol1 is a metamorphosed branch4 8,and1 further1 the flowers being abortive branches1 whatever the laws are of the arrangement of branches with respect to each other1 the same will be the laws of the flowers with respect to each other4 8,in consequence of a flower and its peduncle being a branch in a particular state1 the rudimentary or metamorphosed leaves which constitute bracte1 floral envelopes1 and sexes1 are subject to exactly the same laws of arrangement as regularly-formed leaves40#beg ,the idea that the leaf is the principal organ of the plant1 and that from it all the other organs are probably developed1 is worthy the genius of the great ,german poet4 ,every leaf1 a mystery in itself1 is an individual gifted with peculiar powers2 they congregate in families1 and each one ministers to the formation of the branch on which it hangs1 and to the main trunk of the tree of which it is a member4 ,the tree represents a world1 every part exhibiting a mutual dependence4 8,the one red leaf1 the last of its clan1 ,that dances as often as dance it can2 ,hanging so light and hanging so high1 ,on the topmost twig that looks up at the sky10 is influenced by1 and influences1 the lowest root which pierces the humid soil4 ,like whispering voices1 the trembling leaves sing rejoicingly in the breeze and summer sunshine1 and they tremble alike with agony when the equinoctial gale rends them from the parent stalk4 ,the influences which pervade the whole1 making up the sum of vital force1 are disturbed by every movement throughout the system2 a wound on a leaf is known to disturb the whole1 and an injury inflicted on the trunk interferes with the processes which are the functions of every individual leaf4#beh ,the consideration of the physical circumstances necessary to germination and vegetable growth1 brings us acquainted with many remarkable facts4 ,at a temperature below the freezing point1 seeds will not germinate2 at the boiling point of water1 a chemical change is produced in the grain1 and its power of germinating is destroyed4 ,heat1 therefore1 is necessary to the development of the embryo1 but its power must only be exerted within certain prescribed limits3 these limits are only constant for the same class of seeds1 they vary with almost every plant4 ,this is apparent to every one1 in the different periods required for germination by the seeds of dissimilar vegetables4 ,the seed is placed in the soil2 shade is always--absolute darkness sometimes--necessary for the success of the germinating process4 ,we have seen that the first operation of nature is purely a chemical one1 but this manifestation of affinity is due to an exertion of force1 which is directly dependent upon solar power4 ,the seed is buried in the soil1 when the genial showers of spring1 and the increasing temperature of the earth1 furnish the required conditions for this chemistry of life1 and the plant eventually springs into sunshine4 ,thus we obtain evidence that even through some depth of soil the solar power1 whatever it may be1 is efficient1 and that under its excitement the first spring of life1 in the germ1 is effected4 ,the cotyledons and the plumule being formed1 the plant undergoes a remarkable change4 ,the seed1 like an animal1 absorbed oxygen and exhaled carbonic acid2 the first leaves secrete carbon from carbonic acid inspired1 and send forth1 as useless to the plant1 an excess of oxygen gas4 ,this power of decomposing carbonic acid is a vital function which belongs to the leaves and bark4 ,it has been stated1 on the authority of ,liebig1 that during the night the plant acts only as a mere bundle of fibres1--that it allows of the circulation of carbonic acid and its evaporation1 unchanged4 ,in his eagerness to support his chemical hypothesis of respiration1 the able chemist neglected to inquire if this was absolutely correct4 ,the healthy plant never ceases to decompose carbonic acid during one moment of its existence2 but during the night1 when the excitement of light is removed1 and the plant reposes1 its vital powers are at their minimum of action1 and a much less quantity is decomposed than when a stimulating sun1 by the action of its rays1 is compelling the exertion of every vital function4 ,during this process1 we have another example of natural organic chemistry4 ,the four inorganic elements of which the vegetable kingdom is composed--oxygen1 hydrogen1 nitrogen1 and carbon--are absorbed as air or moisture by the leaves and through the roots1 and the great phenomenon of vegetable life is the conversion of these to an organic condition4 ,sugar and gum are constantly produced1 and from these1 by combination with atmospheric nitrogen1 a proteine compound is formed1 which is an essential element in the progress of development4#bei ,plants growing in the light are beautifully green1 the intensity of colouring increasing with the brilliancy of the light4 ,those which are grown in the dark are etiolated1 their tissues are weak and succulent1 their leaves of a pale yellow4 ,it is1 therefore1 evident that the formation of this chlorophylle--as the green colouring matter of leaves is called--results from some action determined by the sun's rays4 ,chlorophylle is a carbonaceous compound formed in the leaves1 serving1 it would appear1 many purposes in the process of assimilation4 ,in the dark the plant still requires carbon for its further development1 and growing slowly1 it removes it from the leaves1 decomposing the chlorophylle1 and supports its weak existence by preying on parts of its own structure1 until at length1 this being exhausted1 it actually perishes of starvation4 ,plants always turn towards the light3 the guiding power we know not1 but the evidence of some impulsive or attracting force is strong2 and the purpose for which they are constituted to obey it1 is proved to be the dependence of vegetable existence upon luminous power4 ,light is not1 however1 alone sufficient to perfect the plant3 another agent is required to aid in the production of flowers and fruits1 and this power is proved to be heat--and heat1 perhaps1 in some peculiar condition4 ,having reached that point of development when the reproductive functions are1 by another change in the chemical operations going on within the vegetable structure1 to be called forth1 it has been found that the heat rays become in a remarkable manner effective4 ,it has also been observed that plants bend from the red1 or calorific rays1 instead of towards them1 as they are found to do to every other ray of the spectrum4 ,from this we may argue that the influence of these rays is to check the vegetation1 and thus to ensure the perfection of the reproductive processes4 ,it has already been stated that we have the means of separating1 to a considerable extent1 the three principles which we discover in the sunbeam1 from each other1 by the use of absorbent media4 ,by a peculiar yellow glass we cut off the chemical principle of the sunbeam1 and admit the passage of the luminous rays only--,,light4 ,by a cobalt blue glass we obstruct the light1 but allow the chemical agent to pass through freely1 without1 indeed1 any loss--,,actinism4 ,by a glass coloured deep blood-red by oxide of gold we obstruct the chemical principle and much of the light1 but such a medium is perfectly transparent to ,,heat4 ,therefore1 this gives us the means of experimenting with either of these principles1 and of examining the parts which they respectively play in the work of organization4 ,some seeds being placed in the soil1 in every respect in their natural conditions1 duly supplied with moisture1 and a uniform and proper temperature maintained1 we place above the soil the three media above named1 and allow one portion to be exposed to all the ordinary influences of the solar rays4 ,the result will be1 that the seeds under the blue glass will germinate long before those which are exposed to the combined influences of the sunshine3 a few of the seeds will struggle into day under the red glass1 but the process of germination is entirely checked under the yellow glass4 ,here we see that the chemical radiations have quickened the chemical changes1 and accelerated the process1 under the red glass1 through which rays having some peculiar chemical action pass2 the germinating process1 though checked1 is not entirely stopped4 ,whereas1 it would appear that under the influences of light which has been deprived of chemical power1 this conversion of the starch into gum and sugar1 which appears to be necessary1 is entirely prevented4 ,if the experiment is continued1 it will be found that under the blue glass the plants grow rapidly1 but weakly2 and that instead of producing leaves and wood they consist chiefly of stalk1 upon which will be seen here and there some abortive attempts to form leaves4 ,when the process of germination has terminated1 if the young plant is brought under the yellow glass1 it grows most healthfully1 and forms an abundance of wood1 the leaves having an unusually dark green colour1 from the formation of a large quantity of chlorophylle4 ,plants do not1 however1 produce flowers with readiness under this medium2 but if1 at the proper period1 they are brought under the red glass1 the flowering and fruiting processes are most effectively completed4#bfj ,these experiments1 simple as they are1 prove to us the importance of light3 the luminous principle of the sunbeam is exciting the vital powers of the plant to decompose carbonic acid and form wood2 and the calorific agent1 possibly under those modifications which have already been noticed as belonging to the parathermic rays1 is essential to the production of flower and fruit4 ,observations1 which have been extended over many years1 prove that with the seasons these solar powers are1 relatively to each other1 subject to an interesting change4 ,in the spring1 the actinic or chemical power prevails1 and during this period its agency is required for the vitalization of the germ4 ,as the summer comes on1 the actinic rays diminish1 and those of light increase4 ,perhaps it would be more strictly correct to say that the luminous intensity being increased1 the chemical power was retarded2 the former expression implies a variation in quantity1 which may not be correct4 ,we see the necessity for this1 since luminous power is required for the secretion of the carbon1 with which the woody fibre is formed1 and also for the elaboration of the proximate principles of the plant4 ,autumn1 the season of fruit1 is characterized by an increase of the heat rays1 and a diminution of the others3 this change being necessary1 as science now teaches us1 for the due production of flower and fruit4 ,the calorific rays of the solar beam1 to which the autumnal phenomena of vegetation appear particularly to belong1 are of a peculiar character4 ,they have been called1 the ,parathermic rays1 and exhibit a curious compound nature4 ,to these rays we may refer the ripening of fruit and grain1 and the browning of the leaf before its fall4 ,may not the rise of the sap in spring be traced to the excitement of either light or actinism1 and its recession1 in the autumn1 to that power from which the plant is found to bend1 and which appears to be their modified form of heat8 ,there can be no doubt that the varieties of climate and the peculiarities of countries1 as it regards their animal and vegetable productions1 are dependent on the same causes4 ,the distribution of species has been referred by some to specific centres of creation around which the plants and animals have spread1 without reference to physical conditions4 ,although centres of creation may be admitted1 these centres themselves have been determined by the physical fitness of each centre to the conditions of the creation1 and in like manner the migration of tribes is solely due to these physical forces we have been considering4 ,in every zone we find that vegetable organization is peculiarly fitted for the considerations by which it is surrounded4 ,under the equator we have the spice-bearing trees1 the nutmeg1 the clove1 the cinnamon1 and the pepper-tree2 there we have also the odoriferous sandal1 the ebony1 the banyan1 and the teak3 we have frankincense1 and myrrh1 and other incense-bearing plants2 the coffee-tree1 the tea-plant1 and the tamarind4 ,a little further north we have the apricot1 the citron1 the peach1 and the walnut4 ,in ,spain1 ,sicily1 and ,italy1 we have the orange and lemon-tree blooming rich with perfume1 and the pomegranate and the myrtle growing wild upon the rocks4 ,beyond the ,alps the vegetation again changes2 instead of the cypress1 the chesnut1 and the cork-tree1 which prevail to the south of them1 we have the hardier oak1 the beech1 and the elm4 ,still further north1 we have the ,scotch and spruce fir and larch4 ,on the northern shores of the ,baltic1 and in that line of latitude1 the hazel alone appears2 and beyond this the hoary alder1 the sycamore1 and the mountain ash4 ,within the ,arctic circle we find the mezereum1 the water-lilies1 and the globe-flowers2 and1 when the weakness of the solar radiations becomes too great even for these1 the reindeer moss still lends an aspect of gladness to the otherwise sterile soil4 ,the cultivation of vegetables depends on the temperature of the clime4 ,the vine flourishes where the mean annual temperature ranges between #ej and #gc1 and it is only cultivated profitably within #cj ,s4 and #ej ,n4 of the equator4 ,to the same limits is confined the cultivation of maize and of olives4 ,cotton is grown profitably up to latitude #df in the ,old ,world1 but only up to #dj in the ,new4 ,we have evidence derived from photographic phenomena1 that the constitution of the solar rays varies with the latitude4 ,the effects of the sun's rays in ,france and ,england in producing chemical change are infinitely more decided than1 with far greater splendour of light1 they are found to be in the lands under or near the equator4 ,indeed1 the remarks made on the variations in the character of the sunbeam with the changing seasons1 may apply equally to the variations in latitude4 ,fungals are among the lowest forms of vegetation1 but in these we have peculiarities which appear to link them with the animal kingdom4 ,marcet found that mushrooms absorbed oxygen1 and disengaged carbonic acid4 ,in all probability this is only a chemical phenomenon of a precisely similar character to that which we know takes place with decaying wood4 ,in the conversion of wood into humus1 oxygen is absorbed1 and combining with the carbon1 it is evolved as carbonic acid4 ,of course we have the peculiar condition of vitality to modify the effect1 and we have1 too1 in this class of plants1 the existence of a larger quantity of nitrogen than is found in any other vegetating substance4 ,these few sketches of remarkable phenomena connected with vegetation are intended to show merely the operations of the physical powers of the universe1 so far as we know them1 upon these particular forms of organization4 ,during the process of germination1 electricity is1 according to ,pouillet1 evolved2 and again1 in ripening fruits1 there appears to be some evidence of electrical currents4 ,vegetables are1 however1 in the growing state1 such good conductors of electricity1 that it is not1 according to the laws of this force1 possible that they should accumulate it2 so that the luminous phenomena stated to have been observed cannot be due to this agency4 ,we know1 however1 that under every condition of change1 whether induced by chemical or calorific action1 electricity is set in motion2 and we have reasons for believing that the excitation of light will also give rise to electrical circulation4 ,the question1 whether plants possess sensation1 whether they have any disposition of parts at all analogous to the nervous system of animals1 has been often put forward1 but as yet the answers have been unsatisfactory4 ,the point is one well worthy all the attention of the vegetable physiologist2 but regarding plants as the link between the animal and the mineral kingdom1--looking upon phyto-chemistry1 as exhibited by them1 as the means employed to produce those more complex organizations which exist in animals1--we necessarily consider plants as mere natural machines for effecting organic arrangements1 and1 as such1 that they cannot possess any nervous sensibility4 ,muscular contraction may be represented in many of their marvellous arrangements2 and any disturbance produced by natural or artificial means would consequently effect a change in the operations of those forces which combine to produce vegetable life4 ,indeed1 the experiments of ,carlo ,matteucci1 already referred to1 prove that an incision across a leaf1 the fracture of a branch1 or the mere bruising of any part of the plant1 interferes with the exercise of that power which1 under the operation of luminous agency1 decomposes carbonic acid1 and effects the assimilation of the other elements4 ,to recapitulate4 ,a plant is an organized creation2 it is so in virtue of certain strange phyto-chemical operations1 which are rendered active by the solar influences involved in the great phenomena of light1 and by the excitation of caloric force mid electrical circulation4 ,it is a striking exemplification of the united action of certain empyreal powers1 which give rise to the combination1 of inorganic principles under such forms that they become capable of obeying the mysterious impulses of life4 ,the poet has imaged the agency of external powers in various shapes of spiritualized beauty4 ,from the goddess ,flora1 and her attendant nymphs1 to the romantic enchantress who called up flowers by the light touch of her wand1 we have1 in all these creations1 foreshadowings of the discovery of those powers which science has shown are essential to vegetable life4 ,a power from without influences the plant2 but the animal is dependent upon a higher agency which is potent within him4 ,the poet's dream pleases the imaginative mind2 and1 associating in our ideas all that is graceful and loveable in the female form1 with that diviner feeling which impresses the soul with the sense of some unseen spirituality1 we perceive in the goddess1 the enchantress1 or the sylph1 pure idealizations of the physical powers4 ,the spirit floating over these forms of beauty1 and adorning them with all the richness of colour--painting the rose1 and giving perfume to the violet--is1 in the poet's mind1 one which ascends to nearly the highest point of etherealization1 and which becomes1 indeed1 to him a spirit of light2 they ride upon the zephyrs1 and they float1 in all the luxury of an empyreal enjoyment1 down to the earth upon a sunbeam4 ,such is the work of the imagination4 ,what is the result of the search of plodding science after truth8 ,the sunbeam has been torn into rays1 and every ray tasked to tell of its ministry4 ,nature has answered to some of the interrogations2 and1 passing over all the earth1 echoed from plant to plant1 we have one universal cry proclaiming that every function of vegetable life is due to the spirits of the sun4 ,the mighty ,adansonia of ,senegal1 hoary with the mosses of five thousand years1--the ,pohon upas in their deadly valleys1--the climbing lianas of the ,guiana forests1--the contorted serpent-cactus on the burning hills1--the oaks1 which spread their branches in our tempered climes1--the glorious flowers of the inter-tropical regions1 and those which gem our virent plains1--the reindeer lichen of northern lands1 and the conferv of the silent pool1--the greatest and humblest creations of the vegetable world1--all proclaim their direct dependence upon the mysterious forces which are bound together in the silver thread of ,light4 ,these undulations1 pulsations too refined for mortal ears1 which quicken and guide these wonderful organisms1 may be indeed regarded as sphered music for ever repeating the ,divine command1 8,let there be ,light10 by the creation of which1 a dark and dreary chaos was moulded into a star of beauty1 capable of radiating brightness to other space-wandering worlds4 ,,footnotes3 #bdh ,percy ,bysshe ,shelley4 #bdi ,experiments on the production of dephlogisticated air from water with various substances3 by ,lieut4-,general ,sir ,benjamin1 ,count of ,rumford2 ,phil4 ,trans41 vol4 lxxvii4 p4 #hd4 #bej ,experiments upon ,vegetables1 discovering their great power of purifying the common air in the ,sunshine1 and of injuring it in the ,shade and at ,night2 to which is joined1 ,a new method of examining the accurate degrees of ,salubrity of the ,atmosphere1 by ,john ,ingenhousz1 ,councillor of the ,court1 and ,body ,physician to their ,imperial and ,royal ,majesties1 ,f4,r4,s41 c4 ,london3 printed for ,p4 ,elmsley1 in the ,strand1 and ,h4 ,payne1 ,pall ,mall1 #aggi4 #bea ,the ,kingdoms of ,nature1 their life and affinity3 by ,dr4 ,c4 ,g4 ,carus2 ,scientific ,memoirs1 vol4 i4 p4 #bbc4 #beb ,in ,biologie1 by ,g4 ,r4 ,treviranus1 vol4 ii4 p4 #cjb1 the following passage occurs3--8,if we expose spring water to the sun in open or even closed transparent vessels1 after a few days bubbles rise from the bottom1 or from the sides of the vessel1 and a green crust is formed at the same time4 ,upon observing this crust through a microscope1 we discover a mass of green particles1 generally of a round or oval form1 very minute1 and overlaid with a transparent mucous covering1 some of them moving freely1 whilst others1 perfectly similar to these1 remain motionless and attached to the sides of the vessel4 ,this motion is sometimes greater than at others4 ,the animalcules frequently lie as if torpid1 but soon recover their former activity40 #bec ,on the ,structure of the ,vegetable ,cell3 by ,mohl4--,scientific ,memoirs1 vol4 iv4 p4 #aac4 ,outlines of ,structural and ,physical ,botany3 by ,henfrey4 #bed ,dr4 ,carus1 in the memoir already quoted1 says3--8,but since1 in the organization of the earth1 light and air1 as constituting a second integrant part1 stand opposed to gravitation1 and since the plant bears a relation1 not only to gravitation1 but to light also1 when its formation is complete it will necessarily present a second anatomical system1 namely1 that of the spiral vessels1 which have been very justly considered1 of late1 as the organs that perform in plants the functions of nerves40 #bee ,mr4 ,crosse's ,experiments in the ,journal of the ,london ,electrical ,society1 and ,mr4 ,weekes in the ,electrical ,magazine1 and a communication appended to ,explanations3 a ,sequel to the ,vestiges of the ,natural ,history of ,creation4 #bef ,die ,metamorphose der ,pflanzen3 ,goethe1 sect4 #gh4 #beg ,lindley's ,elements of ,botany4 #beh ,see the very curious experiments of ,c4 ,matteucci4 ,traduit et extrait du 8,cimento40--,archives des ,sciences ,physiques et ,naturelles2 ,quelques ,expriences sur la ,respiration des ,plantes4 ,nov4 #ahdf4 #bei ,consult ,rural ,economy1 by ,j4 ,b4 ,boussingault2 ,the ,chemical and ,physiological ,balance of ,organic ,nature1 by ,dumas and ,boussingault2 and ,agricultural ,chemistry1 by ,liebig4 #bfj ,the practical value of the discovery now described1 will be best understood from the following letter from ,mr4 ,lawson1 of ,edinburgh3-- ,edinburgh1 #a1 ,george the ,fourth's ,bridge1 ,sept4 #h1 #ahec4 ,,my ,,dear ,,sir1--,i am favoured with yours of the #eth1 relative to my practical experience in the effect of the chemical agency of coloured media on the germination of seeds and the growth of plants4 ,i must first explain that it is our practice to test the germinating powers of all seeds which come into our warehouses before we send them out for sale2 and1 of course1 it is an object to discover1 with as little delay as possible1 the extent that the vital principle is active1 as the value comes to be depreciated in the ratio it is found to be dormant4 ,for instance1 if we sow #ajj seeds of any sort1 and the whole germinate1 the seed will be the highest current value2 but if only #ij germinate1 its value is #aj per cent4 less2 if #hj1 then its value falls #bj per cent4 ,i merely give this detail to show the practical value of this test1 and the influence it exerts on the fluctuation of prices4 ,our usual plan formerly was to sow the seeds to be tested in a hot-bed or frame1 and then watch the progress and note the results4 ,it was usually from eight to fourteen days before we were in a condition to decide on the commercial value of the seed under trial4 ,my attention was1 however1 directed to your excellent work1 8,on the ,physical ,phenomena of ,nature10 about five years ago1 and ,i resolved to put your theory to a practical test4 ,i accordingly had a case made1 the sides of which were formed of glass coloured blue or indigo1 which case ,i attached to a small gas stove for engendering heat2 in the case shelves were fixed in the inside1 on which were placed small pots wherein the seeds to be tested were sown4 ,the results were all that could be looked for3 the seeds freely germinated in from two to five days only1 instead of from eight to fourteen days as before4 ,i have not carried our experiments beyond the germination of seeds1 so that ,i cannot afford practical information as to the effect of other rays on the after culture of plants4 ,i have1 however1 made some trials with the yellow ray in preventing the germination of seeds1 which have been successful2 and ,i have always found the violet ray prejudicial to the growth of the plant after germination4--,i remain1 my dear ,sir1 ,very faithfully yours1 ,,charles ,,lawson4 ,,chapter ,,xv4 ,,phenomena ,,of ,,animal ,,life4 ,distinction between the ,kingdoms of ,nature--,progress of ,animal ,life--,sponges--,polypes--,infusoria--, animalcula--,phosphorescent ,animals--,annelidans--,myriapoda--,anim al ,metamorphoses--,fishes--,birds--,mammal ia--,nervous ,system--,animal ,electricity--,chemical ,influences--,influence of ,light on ,animal ,life--,animal ,heat--,mechanical ,action--,nervous ,excitement--,man and the ,animal ,races1 c4 8,a stone grows2 plants grow and live2 animals grow1 live1 and feel40 ,such were the distinctions made by ,linnus1 between the conditions of the three kingdoms of nature4 ,we cannot1 however1 but regard them as in all respects illogical4 ,the stone--a solid mass of unorganized particles--enlarges1 if placed in suitable conditions1 by the accretion of other similar particles around it2 but it does not1 according to any meaning in which we use the word1 grow4 ,plants and animals grow2 and they differ1 probably1 only in the phenomena of sensation4 ,yet1 the trembling mimosa1 and several other plants1 appear to possess as much feeling as sponges and some of the lower classes of animals4 ,by this definition1 however1 of the celebrated ,swedish naturalist1 we have a popular and simple expression of a great fact4 ,as we have only to examine the question of the agency of the physical forces upon animal life1 we must necessarily confine our attention to the more striking phenomena with which science has made us acquainted2 and1 having briefly traced the apparent order in which the advance of organization proceeded1 we must direct our few concluding remarks to the physico-physiological influences1 which we must confess to know but too imperfectly4 ,we learn that1 during the states of progress which geology1 looking into the arcana of time1 has made us acquainted with1 a great variety of animal forms were brought into existence4 ,they lived their periods4 ,the conditions of the surface of the earth1 the sea1 or the atmosphere1 were altered2 and1 no longer fitted for the enjoyments of the new life1 these races passed away1 and others occupied their places1 which1 in turn1 went through all the stages of growth1 maturity1 and decay2 until at length1 the earth being constituted for the abode of the highest order of animals1 they were called into existence2 and man1 the intellectual monarch of the world1 was placed supreme amongst them all4 ,types of nearly all those forms of life which are found in the fossil state are now in existence2 and if we examine the geographical distribution of animals--the zones of elevation over the surface of the earth1 and the zones of depth in the ocean1--we shall find1 now existing1 animal creations strikingly analogous to the primitive forms and conditions of the earth's inhabitants4 ,from the depths of the ocean we may even now study--as that most indefatigable naturalist1 ,professor ,edward ,forbes1 has done--the varying states of organization under the circumstances of imperfect light and varying temperature4#bfa ,the gradual advance of animal life in the ascending strata has led to many speculations1 ingenious and refined1 on the progressive development of animals4 ,that the changes of the inorganic world have impressed new conditions on the organic structures of animals1 to meet the necessities of their being1 must be admitted4 ,comparative anatomy has demonstrated that such supposed differences really existed between the creatures of secondary formations--those of the tertiary and the present periods4 ,it has been imagined1 but upon debatable foundations1 that the atmosphere1 during the secondary periods1 was highly charged with carbonic acid2 and1 consequently1 that though beneficial to the growth of plants1 and peculiarly fitted for the conditions required by those which the fossil flora makes us acquainted with1 it was not adapted to support any animals above the slow-breathing1 cold-blooded fishes and reptiles4 ,under the action of the super-luxuriant vegetation of these periods1 this carbonic acid is supposed to have been removed1 an addition of oxygen furnished2 and thus1 consequently1 the earth gradually fitted for the abode of warm-blooded and quick-breathing creatures4 ,we do1 indeed1 find a very marked line between the fossil remains of the lias formations which enclose the saurians1 and the wealden1 in which birds make their appearance more numerously than in any previous formation4 ,founded upon these facts1 speculations have been put forth on the gradual development of animals from the lowest up to the highest orders4 ,between the polype and man a continuous series has been imagined1 every link of the chain being traced into connection with the one immediately succeeding it2 and1 through all the divisions1 zoophytes1 fishes1 amphibia1 reptiles1 birds1 and mammalia are seen1 according to this hypothesis1 to be derived by gradual advancement from the preceding orders4 ,the first having given rise to amphibia1--the amphibion gives birth to the reptile1--the reptile advances to the bird1--and from this class is developed the mammal4 ,a slight investigation will convince us that this view has no foundation4 ,although a certain relationship may be found between some of the members of one class1 and those of the other immediately joining it1 yet this is equally discovered to exist towards classes more remote from each other2 and in no one instance can we detect anything like the passage of an animal of one class into an animal of another4 ,until this is done1 we cannot but regard the forms of animal life as distinct creations1 each one fitted for its state of being1 springing from the command of the great ,first ,cause4#bfb ,but it is time to quit these speculative questions1 and proceed to the examination of the general conditions of animal life at the present time4 ,lowest in the scale of animals1 and scarcely distinguishable from a vegetable1 we find the sponge1 attached to and passing its life upon a rock1 exhibiting1 indeed1 less signs of feeling than many of the vegetable tribes4 ,the chemical differences between vegetables and sponges are1 however1 very decided2 and we find in the tissues of the sponge a large quantity of nitrogen1 a true animal element1 which exists1 but in smaller quantities1 in vegetables4 ,these creations1 standing between vegetable and animal life1 possess the singular power of decomposing carbonic acid1 as plants do2 and the water in which they live always contains an excess of free oxygen4 ,the polypes are a remarkably curious class4 8,fixed in large arborescent masses to the rocks of tropical seas1 or in our own climate attached to shells or other submarine substances1 they throw but their ramifications in a thousand beautiful and plant-like forms2 or1 incrusting the rocks at the bottom of the ocean with calcareous earth1 separated from the water which bathes them1 they silently build up reefs and shoals1 justly dreaded by the navigator2 and sometimes giving origin1 as they rise to the surface of the sea1 to islands1 which the lapse of ages clothes with luxuriant verdure1 and peoples with appropriate inhabitants40#bfc ,most of the polypes are fixed and stationary2 but the hydra and some others have the power of changing their positions1 which they do in search of the light of the sun4 ,they do not appear to have organs of sight requiring light2 but still they delight in the solar influences4 ,the most extraordinary fact connected with the hydra is its being multiplied by division4 ,if an incision be made in the side of a hydra1 a young polype soon developes itself2 and if one of these creatures be divided1 it quickly restores the lost portion of its structure4 ,the varieties of the polypes are exceedingly numerous1 and many of them are in the highest degree curious1 and often very beautiful4 ,the actini1 like flowers1 appear to grow from the rocks1 unfolding their tentacula to the light2 and1 in the excitement due to their eagerness for prey1 they exhibit a beautiful play of colours and most interesting forms4 ,microscopic zoophytes of the most curious shapes are found1--all of which attest1 under examination1 the perfection of all created things4 ,infusoria and animalcula1--animals1 many of them1 appearing under the microscope as little more than a transparent jelly1--must be recognized as the most simple of the forms of life4 ,they exist in all waters in uncountable myriads2 and1 minute creatures as they are1 it has been demonstrated that many of the great limestone hills are composed entirely of their remains4 ,the acaleph1 or the phosphorescent animals of the ocean1 are no less curious4 ,from creatures of the most minute size1 they extend to a considerable magnitude1 yet they appear to be little more than animated masses of sea-water4 ,if any one of these sea-jellies1 or jelly-fishes as they are often called 7even the largest varieties of them71 is cast upon the shore1 it is soon1 by the influence of the sun1 converted into a mere fibre no thicker than a cobweb3 an animal weighing seven or eight pounds is very soon reduced to as many grains4 ,there are numerous kinds of these singular creatures1 most of which are remarkable for the powerful phosphorescent light they emit4 ,the beroes and the pulmonigrade shine with an intense white light many feet below the surface1 whilst the ,cestum ,veneris1 or girdle of ,venus1 gliding rapidly along1 presents1 on the edge of the wave1 an undulating riband of flame of considerable length4 ,there can be no doubt that this arises from the emission of phosphorescent matter of an unknown kind from the bodies of these animals4 ,the microscope has made us familiar with the mysteries of a minute creation which we should not otherwise have comprehended4 ,these creatures are found inhabiting the waters and the land1 and they exist in the intestinal structure of plants and animals1 preying upon the nutritive juices which pass through their systems4 ,although these beings are so exceedingly small that even the most practised observer cannot detect them with the naked eye1 they are proved1 by careful examination under the microscope1 to be in many cases elaborately organized4 ,ehrenberg has discovered in them filamentary nerves and nervous masses1 and even vessels appropriated to the circulation of fluids1 showing that they belong really to a high condition of existence4 ,passing over many links in that curious chain which appears to bind the animal kingdom into a complete whole1 we come to the articulata of ,cuvier--the homogangliata of ,owen4 ,all those creatures which we have been hitherto considering are too imperfect in the construction of their simple organizations to maintain a terrestrial existence2 they are1 therefore1 confined to a watery medium4 ,in the articulata1 we have evidences of higher attributes1 and indications of instincts developed in proportion to the increased perfection of organization4 ,commencing with the annelidans1 all of which1 except the earthworms1 are inhabitants of the waters1 we proceed to the myriapoda1 presenting a system intermediate in every respect between that of worms and insects2 we then find embraced in the same order1 the class insecta1 which includes flies and beetles of all kinds2 and1 as the fourth division of articulated beings1 the arachnidans or spiders2 and1 lastly1 the marine tribe of crustaceans4 ,the most remarkable phenomena connected with these animals are the metamorphoses which they undergo4 ,the female butterfly1 for instance1 lays eggs1 which1 when hatched1 produce caterpillars3 these live in this state for some time1 feeding upon vegetables1 and1 after casting their skins as they increase in size1 at last assume an entirely different state1 and1 dormant in their oblong case1 they appear like dead matter4 ,this chrysalis1 or pupa1 is generally preserved from injury by being embedded in the earth1 from which1 after a season1 a beautifully perfect insect escapes1 and1 floating on the breeze of summer1 enjoys its sunshine1 and revels amidst its flowers4 ,no less remarkable is the metamorphosis of the caducibranchiate amphibia1 passing through the true fish condition of the tadpole to the perfect air-breathing and four-footed animal1 the frog4 ,a metamorphosis of the crustaceans1 somewhat similar to that which takes place in insects1 has been of late years creating much discussion amongst naturalists3 but the question appears to be now settled by the careful and long-continued observations of ,mr4 ,thompson and ,mr4 ,r4 ,c4 ,couch4 ,a wide line of demarcation marks the separation of the invertebrata from the four great classes of vertebrate animals--fishes1 reptiles1 birds1 and mammalia4 ,every part of the globe1--the ocean and the inland lake1--the wide and far-winding river1 and the babbling stream1--the mountain and the valley1--the forest with its depth of shade1 and the desert with its intensity of light1--the cold regions of the frost-chained north1 and the fervid clime within the tropics--presents for our study innumerable animals1 each fitted for the conditions to which it is destined2 and through the whole we find a gradual elevation in the scale of intelligence1 until at last1 separated from all by peculiar powers1 we arrive at man himself4 ,in each of these four classes the animals are furnished with a bony skeleton1 which is in the young animal little more than cartilage2 but1 as growth increases1 lime becomes deposited1 and a sufficient degree of hardness is thus produced to support the adult formation4 ,some anatomists have endeavoured to show that even in the mechanical structure of the bony fabrics of animals1 we are enabled to trace a gradual increase in the perfection of arrangement1 from the fish until the most perfect is found in man4 ,many of the mammalia1 however1 are furnished with skeletons which really surpass that of man4 ,these belong to animals which depend for subsistence upon their muscular powers1 and with whom man is1 in this particular1 on no equality4 ,what is the lord of the creation1 compared with the antelope for fleetness1 or with the elephant and many other animals for strength8 ,as we ascend the scale of animal life we find a more perfectly developed nervous system2 and the relative size of the brain1 compared with that of the brute1 is found progressively to increase1 until it arrives at the utmost perfection in man4 ,on the system of nerves depends sensation1 and there can be no doubt that the more exalted the order of intelligence displayed1 the more exquisitely delicate is the nervous system4 ,thus1 in this world1 refined genius must necessarily be attended with a condition of sensibility which1 too frequently1 to the possessor is a state of real disease4 ,it must be evident to every reader that but very few of the striking features of animal life have been mentioned in the rapid survey which has been taken of the progress of animal organization4 ,the subject is so extensive that it would be quite impossible to embrace it within any reasonable limits2 and it furnishes matter so curious and so instructive1 that1 having once entered on it1 it would have been difficult to have made any selection1 and we must have devoted a volume to the sthetics of natural science4 ,passing it by1 therefore1 with the mere outline which has been given1 we must proceed to consider some of the conditions of vitality4 ,bell has proved that one set of nerves is employed in conveying sensation to the brain1 and another set in transferring the desires of the will to the muscles4 ,by the separation of a main branch of one of the nerves of sensation1 although all the operations of life will still proceed1 the organ to which that nerve goes is dead to its particular sense4 ,in like manner1 if one of the nerves of volition is divided1 the member will not obey the inclination of the brain4 ,it is evident1 therefore1 although many of the great phenomena of vital force are dependent on the nervous system1 and the paralysis of a member ensues upon the separation or the disease of a nerve1 that the nerves are but the channels through which certain influences are carried4 ,the vis vit or vital principle--for we are compelled by the imperfection of our knowledge to associate under this one term the ultimate causes of many of the phenomena of life--is a power which1 although constantly employed1 has the capability of continually renewing itself by some inexplicable connection existing between it and many external influences4 ,we know that certain conditions are necessary to the health of animals4 ,diseased digestion1 or any interruption in the circulation of the blood1 destroys the vital force1 and death ensues4 ,the processes of digestion and of the circulation are perfectly understood1 yet we are no nearer the great secret of the living principle4 ,animals are dependent on several external agents for the support of existence4 ,the oxygen of the air is necessary for respiration4 ,animal heat1 as will be shown presently1 is in a great measure dependent upon it4 ,the external heat is so regulated that animal existence is comfortably supported4 ,electricity is without doubt an essential element in the living processes2 and1 indeed1 many physiologists have been inclined to refer vital force to the development of electricity by chemical action in the brain4 ,this view has1 however1 no foundation in experiment beyond that afforded by the appearance of electric currents1 when the brain is excited4 ,this proves no more than that the operations of mind develope physical power in the matter with which it is mysteriously connected4 ,the phenomena of the ,torpedo and ,gymnotus we have already noticed1#bfd and there are other creatures which certainly possess the power of secreting and discharging electricity4 ,galvani's experiments1 and those of ,aldini1 appear to show--and the more delicate researches of ,matteucci have satisfactorily determined--that currents of electricity are always circulating in the animal frame2--that positive electricity is constantly passing from the interior to the exterior of a muscle4 ,matteucci1 by arranging a series of muscles1 has formed an electric pile of some energy4#bfe ,these currents have been detected in man1 in pigeons1 fowls1 eels1 and frogs4 ,in the human body it is evident a large quantity of electricity exists in a state of equilibrium4 ,du ,bois ,raymond has shown that we may by mere muscular motion give rise to electric currents which can be measured by the galvanometer4 ,this1 however1 may be said of every substance4 ,it is perhaps more easily disturbed in the human system2 indeed1 the manifestation of sparks from the hair and other parts of the body by friction is not uncommon4 ,every chemical action1 it has been already shown1 gives rise to electrical manifestations2 and the animal body is a laboratory1 beautifully fitted with apparatus1 in which nearly every chemical process is going on4 ,it has been proved that acid and alkaline principles are constantly acting upon each other through the tissues of the animal frame2 and we have the curious phenomena of endosmose and exosmose in constant effort1 and catalysis or surface force1 operating in a mysterious manner4#bff ,with the refined physiological questions connected with the phenomena of sensation we cannot deal1 nor will any argument be adduced for or against the hypothesis which would refer these phenomena to some extraordinary development of electric force in the brain4 ,the entire subject appears to stand beyond the true limits of science1 and every attempt to pass it is invariably found to lead to a confused mysticism1 in which the real and the ideal are strangely confounded4 ,science stops short of the phenomena of vital action4 ,we cannot1 however1 but refer to the idea entertained by many that the brain is an electric battery1 and the nerves a system of conductors4 ,on this view ,sir ,john ,herschel remarks3--8,if the brain be an electric pile constantly in action1 it may be conceived to discharge itself at regular intervals1 when the tension of the electricity reaches a certain point1 along the nerves which communicate with the heart1 and thus excite the pulsation of that organ40 ,priestley1 however1 appears to have been the first to promulgate this idea4 ,light is an essential element in producing the grand phenomenon of life1 though its action is ill understood4 ,where there is light1 there is life1 and any deprivation of this principle is rapidly followed by disease of the animal frame1 and the destruction of the mental faculties4 ,we have proof of this in the squalor of those whose necessities compel them to labour in places to which the blessings of sunshine never penetrate1 as in our coal-mines1 where men having everything necessary for health1 except light1 exhibit a singularly unhealthy appearance4 ,the state of fatuity and wretchedness to which those individuals have been reduced who have been subjected for years to incarceration in dark dungeons1 may be referred to the same deprivation4 ,again1 in the peculiar aspect of those people who inhabit different regions of the earth under varying influences of light1 we see evidence of the powerful effects of solar action4 ,other forces1 as yet undiscovered1 may1 in all probability do1 exert decided influences on the animal economy2 but1 although we recognize many effects which we cannot refer to any known causes1 we are perfectly unable to imagine the sources from which they spring4 ,it will be interesting now to examine the phenomena of animal heat1 the consideration of which naturally leads us to consider the digestive system1 the circulatory processes1 and the effects of nervous excitation4 ,the theory1 which attributes animal heat to the combination of the carbon of the food taken into the stomach with the oxygen of the air inspired through the lungs1 has become a very favourite one4 ,it must1 however1 be remembered that it is by no means new4 ,the doctrines of ,brown1 known as the ,brunonian system1 and set forth in his ,elementa ,medicin1 are founded upon similar hasty generalizations4 ,although1 without doubt1 true in a certain degree1 it is not so to the extent to which its advocates would have us believe4 ,that the carbonaceous matter received into the stomach1 after having undergone the process of digestion1 enters into combination with the oxygen breathed through the lungs or absorbed by the skin1 and is given off from the body in the form of carbonic acid1 and that1 during the combination1 heat is produced1 by a process similar to that of ordinary combustion1 is an established fact2 but the idea of referring animal heat entirely to this chemical source1 when there are other well-known causes producing calorific effects1 is an example of the errors into which an ingenious mind may be led1 when eagerly seeking to establish a favourite hypothesis4 ,animal and vegetable diet1 which is composed largely of carbon and hydrogen1 passes into the digestive system1 and becomes converted into the various matters required for the support of the animal structure4 ,the blood is the principal fluid employed in distributing over the system the necessary elements of health and vigour1 and for restoring the waste of the body4 ,this fluid1 in passing through the lungs1 undergoes a very remarkable change1 and not merely assumes a different colour1 but really acquires new properties1 from its exposure to the air with which the cells of these organs are filled4 ,by a true chemical process1 the oxygen is separated from the air1 that oxygen is made to combine with the carbon and hydrogen1 and carbonic acid and water are formed4 ,these are liberated and thrown off from the body either through the lungs or by the skin4 ,in the processes of life1 as far as we are enabled to trace them1 we see actions going on which are referred to certain causes which we appear to explain4 ,thus1 the combination of the oxygen of the air with the carbon of the blood is truly designated a case of chemical affinity2 and we find that in endeavouring to imitate the processes of nature in the laboratory1 we are1 to a certain extent1 successful4 ,we can combine carbon and oxygen to produce carbonic acid2 and we know that the result of that combination is the development of certain definite quantities of heat4 ,let us examine the conditions of this chemical phenomenon1 and we shall find that in the natural and artificial processes1--for we must be allowed to make that distinction1--there are analogous circumstances4 ,if we place a piece of pure carbon1 a lump of charcoal or a diamond1 in a vessel of air1 or even of pure oxygen gas1 no change will take place in either of these elements1 and1 however long they may be kept together1 they will still be found as carbon or diamond1 and oxygen gas4 ,if we apply heat to the carbon until it becomes incandescent1 it immediately begins to combine with the oxygen gas1--it burns2--after a little time all the carbon has disappeared1 and we shall find1 if the experiment has been properly made1 that a gas is left behind which is distinguished by properties in every respect the reverse of those of oxygen1 supporting neither life nor combustion1 whereas oxygen gives increased vigour to both4 ,we have now1 indeed1 carbonic acid gas formed by the union of the two principles4 ,a dead mass of animal matter may be placed in oxygen gas1 and1 unless some peculiar conditions are in some way brought about1 no change will take place2 but1 if it were possible to apply the spark of life to it1 as we light up the spark in the other case1 or if1 as that is beyond the power of man1 we substitute a living creature1 a combination between the carbon of the animal and the gas will immediately begin1 and carbonic acid will be formed by the waste of animal matter1 as in the other case it is by the destruction of the carbon2 and1 if there is not a fresh supply given1 the animal must die1 from the exhaustion of its fabric4 ,now1 in both these cases1 it is clear that1 although this chemical union is a proximate cause of heat1 there must be existing some power superior to it1 as the ultimate cause thereof4 ,the slow combustion 7eremacausis7 of vegetable matter1 decomposing under the influence of moisture and the air1 does not present similar conditions to those of the human body1 although it has been insisted upon to be in every respect analogous4 ,that the results resemble each other is true1 but we must carefully distinguish between effects and causes2 and the results of chemical decomposition in inert matter differ from those in the living organism4 ,the vegetable matter has lost the principle of organic life1 and1 that gone1 the tendency of all things being to be resolved into their most simple forms1 a disunion of the elements commences3 oxygen1 hydrogen1 and carbon pass off either in the gaseous state or as water1 whilst some carbon is liberated in a very finely-divided condition1 and enters slowly into combination with oxygen supplied by the water or the air4 ,hydrogenous compounds are at the same time formed1 and1 under all these circumstances1 as in all other chemical phenomena1 an alteration of temperature results4 ,heat results from the chemical changes1 and eventually true combustion begins4 ,the animal tissue may act in the same way as platina has already been shown to act in producing combination between gases2 but of this we have no proof4 ,we know that electricity is capable of producing the required conditions1 and we also learn1 from the beautiful researches of ,faraday1 that the quantity of electricity developed during decomposition is exactly equal to that required to effect the combination of the same elements4 ,thus it is quite clear that1 during the combination of the carbon of the blood with the oxygen of the air1 a large amount of electricity must become latent in the compound4 ,the source of this we know not3 it may be derived from some secret spring within the living structure1 or it may be gathered from the matter surrounding it4 ,there is much in nervous excitation which appears like electrical phenomena1 and attempts have been frequently made to refer sensation to the agency of electricity4 ,but these are the dreams of the ingenious1 for which there is but little waking reality4 ,every mechanical movement of the body occasions the development of heat2 every exertion of the muscles produces sensible warmth2 and1 indeed1 it can be shown by experiment that every expansion of muscular fibre is attended with the escape of caloric1 and its contraction with the absorption of it4 ,there are few operations of the mind which do not excite the latent caloric of the body1 and frequently we find it manifested in a very remarkable manner by a suddenly-awakened feeling4 ,the poet1 in the pleasure of creation1 glows with the ardour of his mind1 and the blush of the innocent is but the exhibition of the phenomenon under some nervous excitation1 produced by a spirit-disturbing thought4 ,thus we see that the processes of digestion and respiration are not the only sources of animal heat1 but that many others exist to which much of the natural temperature of the body must be referred4 ,so much that is mysterious belongs to the phenomena of life1 that superstition has had a wide scope for the exercise of its influence2 and through all ages a powerful party of mankind have imagined that the spirit of human curiosity must be checked before it advances to remove the veil from any physiological causes4 ,hence it is that even at the present day so much that stands between what1 in our ignorance1 we call the real and the supernatural1 remains uninvestigated4 ,even those men whose minds are sceptical upon any development of the truths of great natural phenomena1--who1 at all events1 will have proof before they admit the evidence1 are ready to give credit to the grossest absurdities which may be palmed upon them by ingenious charlatans1 where the subject is man and his relations to the spiritual world4 ,man1 and the races of animals by which he is surrounded1 present a very striking group1 consider them in whatever light we please4 ,the gradual improvement of organic form1 and the consequent increase of sensibility1 and eventually the development of reason1 are the grandest feature of animated creation4 ,the conditions as to number even of the various classes are not the least remarkable phenomena of life4 ,in the lowest orders of animals1 creatures of imperfect organization1--consequently those to whom the conditions of pain must be nearly unknown1--increase by countless myriads4 ,of the infusoria and other beings1 entire mountains have been formed1 although microscopes of the highest powers are required to detect an individual4 ,higher in the scale1 even among insects1 the same remarkable conditions of increase are observed4 ,some silkworms lay from #a1jjj to #b1jjj eggs2 the wasp deposits #c1jjj2 the ant from #d1jjj to #e1jjj4 ,the queen bee lays between #e1jjj and #f1jjj eggs according to ,burmeister2 but ,kirby and ,spence state that in one season the number may amount to #dj1jjj or #ej1jjj4 ,but1 above all1 the white ant 7,termes fatalis7 produces #hf1djj eggs each day1 which1 continuing for a lunar month1 gives the astonishing number of #b1dai1bjj1 a number far exceeding that produced by any known animal4 ,these may appear like the statements in which a fictionist might indulge1 but they are the sober truths discovered by the most pains-taking and cautious observers4 ,and it is necessary that such conditions should prevail4 ,these insects1 and all the lower tribes of the animal kingdom1 furnish food for the more elevated races4 ,thousands are born in an hour1 and millions upon millions perish in a day4 ,for the support of organic life1 like matter is required2 and we find that the creatures who are destined to become the prey of others are so constituted that they pass from life with a perfect unconsciousness of suffering4 ,as the animal creation advances in size and strength1 their increase becomes limited2 and thus they are prevented from maintaining by numbers that dominion over the world which they would be enabled from their powers to do1 were their bands more numerous than we now find them4 ,the comparative strength1 too1 of the insect tribes has ever been a subject of wonder and of admiration to the naturalist4 ,the strength of these minute creatures is enormous2 their muscular power1 in relation to their size1 far exceeds that of any other animal4 ,the grasshopper will spring two hundred times the length of its own body4 ,the dragonfly1 by its strength of wing1 will sustain itself in the air for a long summer day with unabated speed4 ,the house-fly makes six hundred strokes with its wings1 which will carry it five feet1 every second4 ,the stag-beetle1 were it the size of the elephant1 would be able to tear up the largest mountains4 ,such are the wonders of the natural world2 from the zoophyte1 growing like a flowering plant#bfg upon an axis filled with living pith--a small remove from the conditions of vegetable life1 upwards through the myriads of breathing things--to man1 we see the dependence of all upon these physical powers which we have been considering4 ,to trace the effects of those great causes through all their mysterious phases is the work of inductive science2 and the truths discovered tend to fit us for the enjoyment of the eternal state of high intelligence to which every human soul aspires4 ,that which the ignorant man calls the supernatural1 the philosopher classes amongst natural phenomena4 ,the ideal of the credulous man becomes the real to him who will bend his mind to the task of inquiry4 ,therefore to attempt to advance our knowledge of the unknown1 to add to the stores of truth1 is an employment worthy the high destiny of the human race4 ,remembering that the revelations of natural science cannot in any way injure the revelation of eternal truth1 but1 on the contrary1 aid to establish in the minds of the doubting a firm conviction of its ,divine origin and of man's high position1 we need never fear that we are proceeding too far with any inquiry1 so long as we are cautious to examine the conditions of our own minds1 that they be not made the dupe of the senses4 ,in the fairies of the hills and valleys1 in the gnomes of the caverns1 in the spirits of the elements1 we have the attempts of the mind1 when the world was young1 to give form to the dim outshadowings of something which was then felt to be hidden behind external nature4 ,in the ,oread1 the ,dryad1 and the ,nereid1 we have1 in like manner1 an embodiment of powers which the poet-philosopher saw in his visions presiding over the mountain1 the forest1 and the ocean4 ,content with these1 invested as they were with poetic beauty1 man for ages held them most religiously sacred2 but the progress of natural science has destroyed this class of creations4 8,great ,pan is dead10 but the mountains are not voiceless2 they speak in a more convincing tone2 and1 instead of the ear catching the dying echo of an obscure truth1 it is gladdened with the full1 clear note of nature in the sweetest voice proclaiming secrets which were unknown to the dreams of superstition4 ,,footnotes3 #bfa ,reports of the ,fauna of the gean3 by ,professor ,forbes4--,reports of the ,british ,association4 ,on the ,physical ,conditions affecting the ,distribution of ,life in the ,sea and the ,atmosphere1 c43 by ,dr4 ,williams4 ,swansea4 #bfb ,the ,vestiges of the ,natural ,history of ,creation4 #bfc ,general ,outline of the ,animal ,kingdom3 by ,professor ,thomas ,rymer ,jones1 ,f4,z4,s4 #bfd ,in addition to the memoirs already referred to1 ,note p4 #baa1 see ,carlisle1 ,on the battery of the ,torpedo1 governed by a voluntary muscle4--,phil4 ,trans41 vol4 xcv4 p4 #aa4 ,todd1 ,experiments on the ,torpedo of the ,cape of ,good ,hope4--,ibid41 vol4 cvi4 p4 #abj4 ,todd1 ,experiments on the ,torpedo ,electricus at ,la ,rochelle4--,ibid41 vol4 cvii4 p4 #cb4 #bfe ,for a concise account of these experiments see ,elements of ,natural ,philosophy3 by ,golding ,bird1 ,a4,m41 ,m4,d41 c4 #crd ,edition1 chap1 xx p4 #ccf4 ,in this work all the most recent researches are given1 and the authorities referred to2 see also ,matteucci's interesting papers already quoted4 #bff ,on the laws according to which the mixing of fluids1 and their penetration into permeable substances1 occurs1 with special reference to the processes in the ,human and ,animal ,organism1 by ,julius ,vogel1 of ,giessen3 translated for the ,cavendish ,society4 ,liebig1 ,on the ,motion of the ,juices in the ,animal ,body4 #bfg ,a ,general ,outline of the ,animal ,kingdom3 by ,thomas ,rymer ,jones1 p4 #ed1 et seq4 ,,chapter ,,xvi4 ,,general ,,conclusions4 ,the ,changes produced on ,physical ,phenomena by the ,movement of the ,solar ,system considered--,exertion of the ,physical ,forces through the ,celestial ,spaces--,the ,balance of ,powers--,varieties of ,matter--,extension of ,matter--,theory of ,nonentity--,a ,material ,creation an indisputable fact--,advantages of the ,study of ,science--,conclusion4 ,we have examined terrestrial phenomena under many of the harmonious conditions which1 with our limited intelligence1 we can reach by the aid of science4 ,from the first exhibition of force1 in the cohesion of two atoms1 onward to the full development of organic form in the highest order of animals1 we have observed strange influences4 ,we have seen the solitary molecule invested with peculiar properties1 and regulated by mighty forces2 we have learned that the modes of motion given to this beautiful sphere produce curious changes in the operation of these powers2 and we may with safety infer that every atom constituting this globe is held in wonderful suspension against every atom of every star1 in the celestial spaces1 even to that bright orb in the centre of the ,pleiades1 around which the entire system of created worlds is supposed to roll4 ,as we move around our own sun--in the limited period of #cfe days1 and round our own axis in #bd hours--we experience transitions from heat to cold1 dependent upon our position in regard to that luminary and the laws which regulate the reception and retention of certain physical forces4 ,may we not therefore conclude1 without being charged with making any violent deduction1 that in the great revolution of our system around the centre of space1 we are undergoing gradual changes which are essential to the great scheme of creation1 though at present incomprehensible to us8 ,in our consideration of the influence of time on the structure of the earth as we find it1 we discovered that1 in ages long past1 the vegetation of the tropics existed upon these northern parts of the globe2 and geological research has also proved that over the same lands the cold of an arctic winter must have long prevailed--the immense glaciers of that period having left the marks of their movements upon the face of the existing rocks4#bfh ,we know that during #c1jjj years no change of temperature has taken place in the ,european climate4 ,the children of ,israel found the date and the vine flourishing in ,canaan2 and they exist there still4 ,arago has shown that a trifling alteration of temperature would have destroyed one or the other of these fruit-bearing trees1 since the vine will not ripen where the mean temperature of the year is higher than #hd1 or the date flourish where it sinks below that degree4 ,how immense1 then1 the duration of time since these changes must have taken place6 ,the #dcb1jjj years of ,oriental mythology is a period scarcely commensurable with these effects2 yet1 to the creature of three-score years1 that period appears an eternity4 ,the thirty-three millions of geographical miles which our solar system traverses annually1 if multiplied by three thousand years1 during which we know no change has taken place1 give us #ii1jjj1jjj1jjj as the distance passed over in that period4 ,how wide1 then1 must have been the journey of the system in space to produce the alteration in the physical powers1 by which these changes have been effected6 ,we have an example1 and a striking one1 of the variations which may be produced in all the physical conditions of a world1 in those disturbances of ,uranus which led to the discovery of ,neptune4 ,for thirty years or more certain perturbations were observed in this distant planet1 the discovery of ,sir ,william ,herschel1 and calculation pointed to some still more remote mass of matter as the cause1 which has been verified by its actual discovery4 ,but now ,uranus is at rest2--quietly that star progresses in its appointed orbit1--,neptune can no longer1 for the present1 cause it to move with greater or less rapidity--they are too remote to produce any sensible influence upon each other4 ,consequently1 for thirty years1 it is evident1 phenomena must have occurred on the surface of ,uranus1 which can be no longer repeated until these two planets again arrive at the same positions in their respective paths which they have occupied since #ahab4 ,these considerations assist us in our attempts to comprehend infinite time and space2 but the human mind fails to advance far in the great sublimity4 ,through every inch of space we have evidence of the exercise of such forces as we have been considering4 ,gravitation chains world to world1 and holds them all suspended from the mystic centre4 ,cohesion binds every mass of matter into a sphere1 while motion exerts a constant power1 which tends to alter the form of the mass4 ,the earth's form--a flattened spheroid--the rings of ,saturn and of ,neptune are the consequences of motion in antagonism to cohesion4 ,heat1 radiating from one planet to another1 does its work in all1 giving variety to matter4 ,light seeks out every world--each trembling star tells of the mystery of its presence4 ,where light and heat are1 chemical action1 as an associated power1 must be present2 and electricity must do its wondrous duties amongst them all4 ,modified by peculiar properties of matter1 they may not manifest themselves in phenomena like those of our terrestrial nature2 but the evidence of light is a sufficient proof of the presence of its kindred elements2 and it is difficult to imagine all these powers in action without producing some form of organization4 ,in the rounded pebble which we gather from the sea-shore1 in the medusa floating bright with all the beauty of prismatic colour in the sun-lit sea1--in the animal1 mighty in his strength1 roaming the labyrinthine forests1 or1 great in intelligence1 looking from this to the mysteries of other worlds1--in all created things around us1 we see direct evidence of a beautiful adjustment of the balance of forces1 and the harmonious arrangement of properties4 ,one atom is removed from a mass and its character is changed2 one force being rendered more active than another1 and the body1 under its influence1 ceases to be the same in condition4 ,the regulation which disposes the arrangements of matter on this earth1 must exist through the celestial spaces1 and every planet bears the same relation to every other glittering mass in heaven's o'erarching canopy1 as one atom bears to another in the pebble1 the medusa1 the lion1 or the man4 ,an indissoluble bond unites them all1 and the grain of sand which lies buried in the depth of one of our primary formations1 holds1 chained to it by these all-pervading forces1 the uncounted worlds which1 like luminous sand1 are sprinkled by the hand of the ,creator through the universe4 ,thus we advance to a conception of the oneness of creation4 ,the vigorous mind of that immortal bard who sang 8of man's first disobedience10 never1 in the highest rapture1 the holiest trance of poetic conception1 dreamed of any natural truths so sublime as those which science has revealed to us4 ,the dependence of all the systems of worlds upon each other1 every dust composing each individual globe being 8weighed in a balance10 the adjustment of the powers by which every physical condition is ordered1 the disposition of matter in the mass of the earth1 and the close relation of the kingdoms of nature1--are all revelations of natural truths1 exalting the mind to the divine conception of the universe4 ,there is a remarkable antagonism displayed in the operation of many of these forces4 ,gravitation and cohesion act in opposition to the repellent influences of caloric4 ,light and heat are often associated in a very remarkable manner2 but they are certainly in their radiant states in antagonism to chemical action1 whether produced by the direct agency of actinic force1 or through the intermediate excitement of the electrical current4#bfi ,and in relation to chemical force1 as manifested in organic combinations1 we have the all-powerful operation of ,,life preventing any exercise of its decomposing power4#bgj ,as world is balanced against world in the universe1 so in the human fabric1 in the vegetable structure1 in the crystallized gem1 or in the rude rock1 force is weighed against force1 and the balance hangs in tranquillity4 ,let but a slight disturbance occasion a vibration of the beam1 and electricity shakes the stoutest heart with terror1 at the might of its devastating power4#bga ,heat melts the hardest rocks1 and the earth trembles with volcanic strugglings2 and actinic agency1 being freed from its chains1 speedily spreads decay over the beautiful1 and renders the lovely repulsive4 ,we know matter in an infinite variety of forms1 from the most ponderous metal to the lightest gas2 and we have it within our power to render the most solid bodies invisible in the condition of vapour4 ,is it not easy1 then1 to understand that matter may exist equally attenuated in relation to hydrogen1 as that gas itself is1 when compared with the metal platinum8 ,a doubt has been raised against this view1 from the difficulty of accounting for the passage of the physical elements through solid masses of matter4 ,if we1 however1 remember that the known gases have the power of transpiration through matter in a remarkable degree1#bgb and that the passage of water through a sieve may be prevented by heat1 it will be at once apparent that the permeation of any radiant body through fixed solid matter is entirely a question of conditions4 ,we can form no idea of the size of the ultimate atom2 we cannot comprehend the degree of etherealization to which matter may be extended4 ,our atmosphere1 we have seen1 is only another condition of the same elements which compose all the organized forms of matter upon the earth1 and1 at the height reached by man1 it is in a state of extreme attenuation4 ,what must be its condition at the distance of forty miles from the earth8 ,according to known laws1 certain phenomena of refraction have led us to set these bounds to the matter constituting our globe3 but it may exist in such a state of tenuity1 that no philosophical instrument constructed by human hands could measure its refracting power2 and who shall declare with certainty that matter itself may not be as far extended as we suppose its influences to be8 8,hast thou perceived the breadth of the earth8 declare if thou knowest it all4 8,knowest thou the ordinances of heaven8 ,canst thou set the dominion thereof in the earth80 ,a cheerless philosophy1 derived from the transcendentalism of the ,german schools1 by an unhappy metaphysical subtlety1 and grafted upon what professes to be a positive philosophy1 but which is not so1 is spreading amongst us1 and would teach us to regard all things as the mere exhibition of properties1 a manifestation of powers2 it believes not in a material creation4 ,the grandeur of the earth1 and the beautiful forms adorning it1 are not entities4 ,yonder exquisite specimen of the skill of man1 in which mind appears to shine through the marble1--that distant mountain which divides the clouds as they are driven by the winds across it1--those trees1 amid whose branches the birds make most melodious music1--this flower1 so redolent of perfume1 so bright in colour1 and so symmetric in form1--and that lovely being who1 a model of beauty and grace1 walks the earth an impersonation of love and charity blended1 making1 indeed1 8a sunshine in a shady place10 are not realities4 ,certain forces combine to produce effects1 all of which unite to deceive poor man into the belief that he is a material being1 and the inhabitant of a material world4 ,there may be ingenuity in the philosophy of this school2 its metaphysics may be of a high order2 but it evidently advances from the real to the ideal with such rapidity1 that every argument is based on an assumption without a proof2 every assumption being merely a type of the philosophy itself1--a baseless fabric1 a transcendental vision4 ,a material creation surrounds us4 ,this earth1 all that it contains1 and the immense hosts of stellar worlds1 are absolute entities1 surrounded with1 and interpenetrated by1 certain exhibitions of creative intelligence1 which perform1 according to fixed laws1 the mighty labours upon which depend the infinite and eternal mutations of matter4 ,the origin of a grain of dust is hidden from our finite comprehensions2 but its existence should be a source of hope1 that those minds which are allowed the privilege of tracing out its marvellous properties1--of examining the empyreal principles upon which its condition1 as a grain of dust1 depends1--and even of reducing these giant elements to do our human bidding1--may1 after a period of probation1 be admitted to the enjoyment of that infinite power to which the great secrets of creation will be unveiled4 ,every motion which the accurate search of the experimentalist has traced1 every principle or power which the physicist has discovered1 every combination which the chemist has detected1 every form which the naturalist has recorded1 involves reflections of an exalting character1 which constitute the elements of the highest poetry4 ,the philosophy of physical science is a grand epic1 the record of natural science a great didactic poem4 ,to study science for its useful applications merely1 is to limit its advantages to purely sensual ends4 ,to pursue science for the sake of the truths it may reveal1 is an endeavour to advance the elements of human happiness through the intelligence of the race4 ,to avail ourselves of facts for the improvement of art and manufactures1 is the duty of every nation moving in the advance of civilization4 ,but to draw from the great truths of science intelligible inferences and masterly deductions1 and from these to advance to new and beautiful abstractions1 is a mental exercise which tends to the refinement and elevation of every human feeling4 ,the mind thus exercised during the mid-day of life1 will find in the twilight of age a divine serenity2 and1 charmed by the music of nature1 which1 like a vesper hymn poured forth from pious souls1 proclaims in devotion's purest strain the departure of day1 he will sink into the repose of that mysterious night which awaits us all1 tranquil in the happy consciousness that the sun of truth will rise in unclouded brilliancy1 and place him in the enjoyment of that intellectual light1 which has ever been among the holiest aspirations of the human race4 ,the task of wielding the wand of science1--of standing a scientific evocator within the charmed circle of its powers1 is one which leads the mind through nature up to nature's ,god4 ,experiment and observation instruct us in the discovery of a fact2--that fact connects itself with natural phenomena1--the ultimate cause of which we learn from ,divine revelation1 and receive in full belief1--but the proximate causes are reserved as trials of man's intelligence2 and every natural truth1 discovered by induction1 enables the contemplative mind to deduce those perfect laws which are exemplifications of the fresh-springing and all enduring ,,poetry ,,of ,,science4 ,,footnotes3 #bfh 8,as to the polishing and grooving of hard rocks1 it has lately been ascertained that glaciers give rise to these effects when pushing forward sand1 pebbles1 and rocky fragments1 and causing them to grate along the bottom4 ,nor can there be any doubt that icebergs1 when they run aground on the floor of the ocean1 imprint similar marks upon it40--,principles of ,geology1 or the modern changes of the ,earth and its ,inhabitants considered as illustrative of ,geology3 by ,charles ,lyell1 ,m4,a41 ,f4,r4,s4 ,travels through the ,alps of ,savoy1 and other parts of the ,pennine ,chain1 with ,observations on the ,phenomena of ,glaciers3 by ,james ,d4 ,forbes1 ,f4,r4,s4 #bfi ,this may be readily proved by the following simple but instructive experiment3--,take two pairs of watch-glasses2 into one pair put a solution of nitrate of silver1 into the other a weak solution of iodide of potassium2 connect the silver solution of each pair with the potash one by a film of cotton1 and carry a platina wire from one glass into the other4 ,place one series in sunshine1 and the other in a dark place4 ,after a few hours it will be found that the little galvanic arrangement in the dark will exhibit1 around the platina wire1 a very pretty crystallization of metallic silver1 but no such change is observable in the other exposed to light4 ,if a yellow glass is interposed between the glass and the sunshine1 the action proceeds as when in the dark4 ,this experiment is naturally suggestive of many others1 and it involves some most important considerations4 #bgj ,in cases of violent death it is often found the gastric juice has1 in a few hours1 dissolved portions of the stomach4--,dr4 ,budd's ,lecture before the ,college of ,physicians4 #bga ,faraday's ,experimental ,researches1 vol4 i42 from which a quotation has already been made1 showing the enormous quantity of electricity which is latent in matter4 #bgb ,on the ,motion of ,gases3 by ,professor ,graham1 ,f4,r4,s4--,phil4 ,trans41 vol4 cxxxvi4 p4 #egc4 ,,index4 ,absorption of heat by air1 water1 and earth1 #gd4 ---- of light1 #abe4 ,acaleph1 or phosphorescent animals1 #chg4 ,actinism1 #aff4 ---- producing chemical change1 #agd4 ---- and light antagonistic1 #agg4 ----1 influence of1 on plants1 #cgb4 ,action of presence--,catalysis1 #bhj4 8,active principles0 of ,newton1 #aa4 ,adams on planet ,neptune1 #cb4 ,adiathermic bodies1 #ie4 ,arial currents dependent on heat1 #hj4 ---- chemical1 #bgd4 ,affinity1 #bib4 ,age of the world1 #djd4 ,aggregation1 attraction of1 #dh4 ----1 crystalline1 #eh4 ,agonic lines1 #bdd4 ,air1 absorption of heat by1 #gd4 ---- density of the1 #cai4 ,alchemy1 ,nature's1 #bic4 ,aldini on animal electricity1 #cic4 ,allotropic conditions of atoms1 #dc4 ,allotropism1 #ccj4 ,allotropy1 #bia4 ,alum1 opacity to heat rays1 #fe4 ,alpinus' theory of matter1 #dg4 ,ammonites of the lias1 #cda4 ,ammoniacal amalgam1 #cbe4 ,ampre's theory of magnetism1 #bci4 ,analogy1 dangers of reasoning by1 #aeb4 ,ancients' knowledge of magnetism1 #bce4 ,animals1 phosphorescence of1 #aed4 ---- respiration of1 #caj4 ---- articulated1 #chh4 ,animal magnetism1 #bfg4 ---- electricity1 #baa1 #cib4 ---- life1 progress of1 #cch4 ----1 phenomena of1 #chc4 ,arago on the surface of the sun1 #abc4 ---- on copying the ,egyptian temples1 #agg4 ---- on magnetic variation1 #bdf4 ,arbor ,dian--silver tree1 #bfa4 ,aristotle on motion1 #aj4 ,atmosphere1 uses of the1 #cai4 ,atmospheric refraction1 #cbb4 ,atomic theory1 #bgh4 ---- volumes1 #bhg4 ,atoms1 allotropic state of1 #dc4 ,atom1 the organic1 #cfj4 ----1 ultimate size of1 #djh4 ----1 the1 and its powers1 #c4 ,attraction1 chemical1 #bge4 ,aurora of the sun1 #ahf4 ,back's account of ,aurora1 #bdi4 ,balance of forces1 #ad4 ,bartholin on ,iceland spar1 #adj4 ,beccaria1 ,father1 on phosphorescence1 #afj4 ,becquerel's experiments on electricity1 #bbg4 ---- on ozone1 #cjj4 ,bell on the nerves1 #cia4 ,belemnites1 #cda4 ,berkeley1 ,bishop1 on motion1 #aj4 ,berzelius on allotropy1 #dd4 ---- on catalysis1 #bha4 ,biela's comet1 #bf4 ,biot on polarization1 #ade4 ,bolognian stone1 #afa4 ,bouguer on the absorption of light by the atmosphere1 #abf4 ,boutigny on heat1 #ajg4 ,boletus igniarius1 #ajb4 ,boyle on motion1 #i4 ,brain and nerves1 #cia4 ,brahminical philosophy1 #bde4 ,brewster1 ,sir ,d41 refers magnetism to the sun1 #bfc4 ---- on magnetism1 #bdg4 ,brown's doctrines of life1 #cie4 ,butterfly1 metamorphosis of1 #chi4 ,cagniard de la ,tour state1 #ajf4 ,calorific transparency1 #fe4 ---- influence on plants1 #cgf4 ,calotype1 the1 #agd4 ,canton's phosphorus1 #afa4 ,carbon1 allotropic state of1 #dc4 ,carboniferous plants1 fossil1 #cci4 ,carbonic acid1 solid1 #aaa4 ---- quantity in atmosphere1 #caa4 ,cassini on magnetic variation1 #bdf4 ,catalysis1 #bhj4 ,cell1 organic1 #cfa4 ,cellini1 ,benvenuto1 on the 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,electrical phosphorescence1 #afj4 ---- action influenced by actinism1 #ahc4 ---- radiations1 #aij4 ---- clock1 #bcc4 ,electro-chemistry1 #bjf4 ,electro culture1 #bbc4 ,electrotype1 the1 #bbi4 ,electro-chemical decomposition1 #bjh4 ,electro-magnetism1 #bdj4 ,electrum1 #aic4 ,elements1 chemical1 #cg1 #bgb4 ----1 atmospheric1 #cbe4 ----1 interchanges of1 #cai4 ,englefield on heat rays1 #fg4 ,eocene formations1 #cdf4 ,equinoxes1 precession of the1 #bdd4 ----1 the vernal and autumnal1 #gg4 ,epicurus' hooked atoms1 #dh4 ,epipolic phenomena1 #abi4 ,eremacausis1 #aje4 ,ether1 hypothesis of an1 #abj4 ,examples of crystallization1 #ei4 ,expansion of bodies by heat1 #if4 ,eye1 mechanism of1 #adi4 ,faraday on ,magnetism of ,crystals1 #ei4 ---- on solidification of gases1 #aab4 ---- on magnetization of light1 #adg4 ---- on the gymnotus1 #baa4 ---- on diamagnetism1 #bed4 ,ferro-magnetic bodies1 #bee4 ,fish ,lizard1 the1 #cda4 ,fixed stars1 light of1 #abb4 ,flint glass1 permeability to heat1 #fe4 ,flora1 fossil1 #cde4 ,flowers1 influences of1 #cag4 ,fluid1 magnetic theory of1 #beb4 ,fluorescence of light1 #acj4 ,forbes1 ,prof4 ,jas41 on vibrations of heated metals1 #ig4 ,forbes1 ,prof4 ,edward1 on zones of life in the ocean1 #abg4 ,forbes on colour of steam1 #cba4 ,force producing motion1 #i4 ---- a cause of motion1 #ag4 ----1 molecular1 #dj4 ---- of crystallization1 #fa4 ,forces1 active1 in matter1 #c4 ----1 balance of1 #ad4 ---- in antagonism1 #djg4 ,form1 change of1 #b4 ---- of surface1 influence of1 on climate1 #cea4 ----1 variety of vegetable1 #cei4 ,foster describes ,northern ,lights1 #bdi4 ,fox1 ,r4 ,w41 on temperature of ,cornish mines1 #ia4 ,franklin on atoms1 #dg4 ,franklin's kite experiment1 #bad4 ,freezing mixtures1 #aaj4 ,freezing1 remarkable phenomena of1 #aab4 ---- of water1 #cjb4 ,friction1 #ag4 ,frictional electricity1 #aii4 ,fraunhofer's dark lines1 #abe4 ,franklin's experiment on heat1 #ge4 ,fusion influenced by pressure1 #ajg4 ,galvanism1 #bja4 ,galvani's 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affinity1 #hh4 ----1 latent1 #aja4 ----1 decomposition by1 #aji1 #bgf4 ----1 scientific knowledge of1 #aad4 ---- developed by combustion of wood equivalent to heat absorbed in growth1 #aaf4 ----1 influence of1 on magnetism1 #bda4 ----1 action of1 on water1 #cjb4 ----1 influence of on plants1 #cga4 ---- essential to life1 #cie4 ,heliography of ,m4 ,niepce1 #agj4 ,herbivorous animals1 #cae4 ,herschel on the nebul1 #bd4 ,herschel1 ,sir ,w41 on heat rays1 #fg4 ,hobbes on the properties of matter1 #h4 ,hopkins on the temperature of fusion1 #ajg4 ,huyghens on double refraction1 #adj4 ,hydra1 the1 #chg4 ,hydrogen1 peroxide of1 #bih4 ---- and oxygen1 #bhi1 #big4 ,hydro-carbons1 #big4 ,hydro-carbon compounds1 #cjh4 ,hypnotism1 ,mr4 ,braid on1 #bfi4 ,ice1 #cja4 ,ichthyosaurus1 the1 #cda4 ,igneous rocks1 #cce4 ,ignition by chemical action1 #ajb4 ,iguanodon1 the1 #cdc4 ,incandescence1 temperature of1 #fi-ajj4 ,influences of matter on heat1 #gi4 ,infusoria and animalcul1 #chg4 ,interference of 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light on1 #aec4 ---- dependent on light1 #afd4 ----1 vegetable1 #cfb4 ----1 mysteries of1 #cih4 ,light1 #aah4 ---- essential to life1 #ci4 ---- of fixed stars1 #abb4 ----1 transparency to1 #abd4 ----1 transmission of1 through different media1 #abh4 ----1 absorption of1 #abe4 ----1 interference of1 #ach4 ----1 polarized condition of1 #ada4 ----1 magnetization of1 #adf4 ----1 artificial1 #afb4 ----1 influence of1 on plants1 #cgc4 ---- and heat1 correlation of1 #fd4 ,lightning conductors1 #bae4 ,lindley on the leaf1 #cgj4 ,lubbock1 ,sir ,j41 on shooting stars1 #bb4 ,lodes1 mineral1 electricity of1 #bbe4 ,luminous and actinic rays distinguished1 #agf4 ,machine electricity1 #bji4 ,magellanic clouds1 #be4 ,magnetic curves1 #bcf4 ---- iron ore1 #bcg4 ---- polarity1 #bcg4 ---- points of convergence1 #bdd4 ---- poles of the earth1 #bde4 ---- intensity1 #bdg ---- storms1 #bdi4 ---- lines of no variation1 #bdc4 ,magnetism1 #bce4 ---- induced1 #bch4 ---- influenced by heat1 #bdb4 ----1 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#bbb4 ,metamorphic rocks1 #ccf4 ,metamorphoses of animals1 #chi4 ,mexico1 ,gulf of1 warmth of the1 #ha4 ,mica1 black1 transparency to heat1 #ff4 ,miller1 ,dr41 on dark lines of the spectrum1 #abf4 ,mineral veins1 electricity of1 #bbe4 ,mines1 ,cornish1 temperature of1 #ia4 ,miocene formations1 #cdf4 ,mirrors1 magic1 #aia4 ,mitscherlich on expansion of crystals by heat1 #beg4 ,molecular forces1 #ce1 #dj4 ----1 compound action of1 #bgi4 ,molecules1 ,dumas on1 #ci4 ---- combination1 #bgg4 ,morichini and ,carpi on magnetism of violet rays of light1 #bfc4 ,moser on invisible light1 #ahi4 ,motion1 #g4 ---- a property of matter1 #h4 ----1 principles of1 #aj4 ---- of the earth1 #ab4 ---- round an axis shows the earth's motion1 #ah4 ----1 influence of1 on form1 #cb4 ,mountain ranges probably determined by magnetic force1 #bfb4 ,multiplication of life1 #cii4 ,musical notes produced by heat1 #ig4 ,muscular contraction by electricity1 #bjb4 ,musschenbroek of ,leyden1 #aih4 ,mythology1 ancient1 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#bdc4 ,solar phosphori1 #afa4 ,somerville1 ,mrs41 magnetises needles by light1 #bfc4 ,sound and light1 analogy of1 #aea4 ,spectra produced by polarization of light1 #add4 ,spectrum1 dark lines of1 #abe4 ,spheroidal condition of fluids1 #ajg4 ,spontaneous ignition1 #cjg4 ,stahl on phlogiston1 #cje4 ,stars1 shooting1 theories of1 #ba4 ,steel ornaments incandescent1 #acg4 ,stereoscope1 the1 #aea4 ,stokes1 ,prof41 on fluorescence1 #acj4 ,stratified formations1 #ccd4 ,strength of animals1 #djj4 ,structure1 influence of1 on magnetism1 #bef4 ----1 relation of1 to physical phenomena1 #beg4 ,struv on motion of solar system1 #ab4 ,substitution1 chemical1 #bgi4 ----1 law of1 #bhh4 ,substances1 all1 electric1 #aig4 ,subterranean temperature1 #ia4 ,sulphuric acid1 permeability to heat1 #fe4 ,surfaces1 action of1 #bhb4 ,sulzar on galvanism1 #bja4 ,sulphuretted hydrogen1 solid1 #aaa4 ,sun1 the central1 #bh4 ----1 the source of light1 #aba4 ----1 physical state of the1 #abc4 ----1 a magnetic centre1 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incandescence1 #ajj4 ,wells1 ,dr41 on dew1 #hd4 ,wiedemann on electrical vibrations1 #beg4 ,wenzel's proportional numbers1 #bgg4 ,winds dependent on heat1 #hj4 ,wollaston notices dark lines in spectrum1 #abe4 ,world1 its age1 #djd4 ,young on molecular forces1 #di4 ,zodiacal light1 #be4 ,zoophytes1 microscopic1 #chg4 ,,the ,,end4 ,wilson and ,ogilvy1 #eg1 ,skinner ,street1 ,snowhill1 ,london4 ,,bohn',s ,,books4 ,,bohn',s ,,standard ,,library4 ,post #hvo41 ,elegantly ,printed1 and bound in ,cloth1 at #cs4 #f;d4 per ,vol4 #a4 ,,the ,,miscellaneous ,,works ,,and ,,remains ,,of ,,the ,,rev4 ,,robert ,,hall1 with ,memoir by ,,dr4 ,,gregory1 and ,essay by ,,john ,,foster4 ,portrait4 #b #c4 ,,roscoe',s ,,life ,,and ,,pontificate ,,of ,,leo ,x4 ,edited by his ,son1 with the ,copyright ,notes1 ,documents1 c4 ,in #b ,vols4 ,portraits4 #d4 ,,schlegel',s ,,lectures ,,on ,,the ,,philosophy ,,of ,,history4 ,translated from the ,german1 with a ,memoir by ,j4 ,b4 ,,robertson1 ,esq4 ,portrait4 #e #f4 ,,sismondi',s ,,history ,,of ,,the ,,literature ,,of ,,the ,,south ,,of ,,europe4 ,translated by ,,roscoe4 ,in #b ,vols4 ,portraits4 #g4 ,,roscoe',s ,,life ,,of ,,lorenzo ,,de ,,medici1 with the ,copyright ,notes1 c4 #h4 ,,schlegel',s ,,lectures ,,on ,,dramatic ,,literature4 ,portrait4 #i #aa4 ,,beckmann',s ,,history ,,of ,,inventions1 ,,discoveries1 ,,and ,,origins4 ,fourth ,edition1 revised and enlarged4 ,in #b ,vols4 ,portraits4 #aj4 ,,schiller',s ,,history ,,of ,,the ,,thirty ,,years' ,,war ,,and ,,revolt ,,of ,,the ,,netherlands4 ,translated by ,a4 ,j4 ,w4 ,,morrison4 ,portrait4 #ab4 ,,schiller',s ,,works4 ,vol4 ,,ii4 ,conclusion of 8,the ,revolt of the ,netherlands20 8,wallenstein's ,camp20 8,the ,piccolomini20 8,the ,death of ,wallenstein20 and 8,wilhelm ,tell40 ,with ,portrait of ,wallenstein4 #ac4 ,,memoirs ,,of ,,the ,,life ,,of ,,colonel ,,hutchinson4 ,by his ,widow3 with an 8,account of the ,siege of ,lathom ,house40 ,portrait4 #ad4 ,,memoirs ,,of ,,benvenuto ,,cellini1 by ,,himself4 ,by ,,roscoe4 ,portrait4 #ae1 #ah1 #bb4 ,,coxe',s ,,history ,,of ,,the ,,house ,,of ,,austria1 from the foundation of the ,monarchy1 #abah-agib4 ,complete in #c vols4 ,portraits4 #af1 #ai1 #bc4 ,,lanzi',s ,,history ,,of ,,painting4 ,by ,,roscoe4 ,in #c ,vols4 ,portraits4 #ag4 ,,ockley',s ,,history ,,of ,,the ,,saracens4 ,revised and ,completed4 ,portrait4 #bj4 ,,schiller',s ,,works4 ,vol4 ,,iii4 8,don ,carlos10 8,mary ,stuart10 8,maid of ,orleans10 and 8,bride of ,messina40 ,frontispiece4 #ba1 #bf1 #cc4 ,,lamartine',s ,,history ,,of ,,the ,,girondists2 or1 ,memoirs of the ,french ,revolution1 from unpublished sources4 ,in #c ,vols4 ,portraits4 #bd4 ,,machiavelli',s ,,history ,,of ,,florence1 ,,prince1 c4 ,portrait4 #be4 ,,schlegel',s ,,lectures ,,on ,,the ,,philosophy ,,of ,,life ,,and ,,the ,,philosophy ,,of ,,language4 ,translated by ,a4 ,j4 ,w4 ,,morrison4 #bg1 #cb1 #cf4 ,,ranke',s ,,history ,,of ,,the ,,popes4 ,translated by ,e4 ,,foster4 ,in #c ,vols4 ,portraits4 7,the only complete ,english translation47 #bh1 #cj1 #cd4 ,,coxe',s ,,memoirs ,,of ,,the ,,duke ,,of ,,marlborough4 ,in #c ,vols4 ,portraits4 999999 ,,atlas1 of #bf fine large ,maps and ,plans of ,marlborough's ,campaigns1 7being all those published in the original edition at #ab #abs47 #dto4 #ajs4 #f;d4 #bi4 ,,sheridan',s ,,dramatic ,,works ,,and ,,life4 ,portrait4 #ca4 ,,goethe',s ,,works4 ,vol4 ,i4 ,his ,autobiography4 #ac ,books4 ,portrait4 #ce4 ,,wheatley ,,on ,,the ,,common ,,prayer4 ,frontispiece4 #cg4 ,,milton',s ,,prose ,,works4 ,vol4 ,i4 ,portrait4 #ch1 #da1 #de4 ,,menzel',s ,,history ,,of ,,germany4 ,complete in #c ,vols4 ,portrait4 #ci4 ,,milton',s ,,prose ,,works4 ,vol4 ,,ii4 ,frontispiece4 #dj4 ,,milton',s ,,prose ,,works4 ,vol4 ,,iii4 ,portrait of ,laud4 #db4 ,,schlegel',s ,,sthetic ,,and ,,miscellaneous ,,works4 #dc4 ,,goethe',s ,,works4 ,vol4 ,,ii4 ,remainder of his ,autobiography1 and ,travels4 #dd4 ,,schiller',s ,,works4 ,vol4 ,,iv4 8,the ,robbers10 8,fiesko10 8,love and ,intrigue10 and 8,the ,ghost-,seer40 ,translated by ,,henry ,g4 ,,bohn4 #df4 ,,schlegel',s ,,lectures ,,on ,,modern ,,history4 #dg4 ,,lamartine',s ,,history ,,of ,,the ,,french ,,revolution ,,of #ahdh4 #dh #ej4 ,,junius',s ,,letters1 with ,notes1 ,additions1 ,essay1 ,index1 c4 #b ,vols4 #di1 #ee1 #fj1 #fe1 #ga4 ,,vasari',s ,,lives ,,of ,,the ,,most ,,celebrated ,,painters1 ,,sculptors1 ,,and ,,architects4 ,translated by ,,mrs4 ,,foster1 with ,notes4 ,complete in #e ,vols41 with ,index4 #ea4 ,,taylor',s 7,,jeremy7 ,,holy ,,living ,,and ,,dying4 ,portrait4 #eb4 ,,goethe',s ,,works4 ,vol4 ,,iii4 8,faust10 8,iphigenia10 8,torquato ,tasso10 and 8,egmont40 ,translated by ,miss ,,swanwick4 ,with 8,goetz von ,berlichingen10 translated by ,,sir ,,walter ,,scott4 #ec1 #ef1 #eh1 #fa1 #ff1 #fg1 #ge4 ,,neander',s ,,church ,,history4 ,carefully revised by the ,,rev4 ,a4 ,j4 ,w4 ,,morrison4 #ed4 ,,neander',s ,,life ,,of ,,christ4 #eg1 #fd4 ,,neander',s ,,planting ,,of ,,christianity1 ,,antignostikus1 #b ,vols4 #ei4 ,,gregory',s 7,,dr47 ,,letters ,,on ,,the ,,christian ,,religion4 #fb #fc4 ,,james' 7,g4 ,p4 ,r47 ,,louis ,,xiv4 ,complete in #b ,vols4 ,portraits4 #fh #gj4 ,,sir ,,joshua ,,reynolds' ,,literary ,,works1 with ,memoir1 #b ,vols4 ,port4 #fi4 ,,andrew ,,fuller',s ,,principal ,,works4 ,portrait4 #gb4 ,,butler',s ,,analogy ,,of ,,religion1 ,,and ,,sermons1 with ,notes1 c4 ,port4 #gc4 ,,miss ,,bremer',s ,,works4 ,translated by ,,mary ,,howitt4 ,new ,edition1 revised4 ,vol4 ,i4 8,the ,neighbours10 and other ,tales4 ,post #hvo4 ,portrait4 #cs4 #f;d4 #gd4 ,,neander',s ,,memorials ,,of ,,christian ,,life ,,in ,,the ,,early ,,and ,,middle ,,ages 7including his 8,light in ,dark ,places074 ,post #hvo4 #cs4 #f;d4 ,uniform with the ,,standard ,,library1 price #cs4 #f;d41 ,,bohn',s ,,extra ,,volumes4 #a4 ,,grammont',s ,,memoirs ,,of ,,the ,,court ,,of ,,charles ,,ii4 ,portrait4 #b #c4 ,,rabelais' ,,works4 ,complete in #b ,vols4 ,portrait4 #d4 ,,count ,,hamilton',s ,,fairy ,,tales4 ,portrait4 ,uniform with the ,,standard ,,library1 price #es4 7excepting 8,cosmos10 which is only #cs4 #f;d41 and ,mantell's 8,petrifactions10 which is #fs471 ,,bohn',s ,,scientific ,,library4 #a4 ,,staunton',s ,,chess ,,player',s ,,hand-,,book1 with ,diagrams4 #b4 ,,lectures ,,on ,,painting1 by ,,the ,,royal ,,academicians4 #c1 #d1 #h1 #ae4 ,,humboldt',s ,,cosmos2 or1 ,sketch of a ,physical ,description of the ,universe4 ,translated1 with ,notes1 by ,e4 ,c4 ,,otte4 ,in #d ,vols41 with fine ,portrait4 ,this ,translation 7though published at so low a price7 is more complete than any other4 ,the ,notes are placed beneath the text4 ,humboldt's analytical summaries1 and the passages hitherto suppressed1 are included2 and comprehensive ,indices subjoined4 #cs4 #f;d4 per ,volume4 #e4 ,,staunton',s ,,chess ,,player',s ,,companion1 comprising a ,new ,treatise on ,odds1 a ,collection of ,match ,games1 ,original ,problems1 c4 #f4 ,,hand-,,book ,,of ,,games1 by ,,various ,,amateurs and ,,professors4 #g4 ,,humboldt',s ,,views ,,of ,,nature1 with coloured view of ,chimborazo1 c4 #i4 ,,richardson',s ,,geology1 ,,and ,,pal,,ontology1 ,revised by ,dr4 ,,wright1 with upwards of #djj ,illustrations on ,wood4 #aj4 ,,stockhardt',s ,,principles ,,of ,,chemistry4 ,exemplified in ,simple ,experiments1 with upwards of #bgj ,illustrations4 #aa4 ,,dr4 ,g4 ,a4 ,,mantell',s ,,petrifactions ,,and ,,their ,,teachings2 ,a ,hand-,book to the ,fossils in the ,british ,museum4 ,beautiful ,wood ,engravings4 #fs4 #ab4 ,,agassiz ,,and ,,gould',s ,,comparative ,,physiology4 ,new and ,enlarged ,edition1 with nearly #djj fine ,illustrations4 #ac #ai4 ,,humboldt',s ,,personal ,,narrative ,,of ,,his ,,travels ,,in ,,america4 ,vols4 ,i4 ,,ii4 7to be completed in #c ,volumes47 #ad4 ,,pye ,,smith',s ,,geology ,,and ,,scripture4 ,fifth ,edition1 with ,memoir4 #af4 ,,oersted',s ,,soul ,,in ,,nature1 ,c4 ,portrait4 #ag4 ,,staunton',s ,,chess ,,tournament1 with ,diagrams4 #ah #ai4 ,,bridgewater ,,treatises4 ,,kirby on the ,history1 ,habits1 and ,instincts of ,animals2 ,edited by ,t4 ,,rymer ,,jones4 ,in #b ,vols4 ,many ,illustrations4 ,,uniform ,,with ,,the ,,standard ,,library1 ,,barbauld',s 7,,mrs47 ,,selections ,,from ,,the ,,spectator1 ,,tatler1 ,,guardian1 ,,and ,,freeholder4 ,in #b ,vols4 #cs4 #f;d4 per ,volume4 ,,british ,,poets1 from ,,milton to ,,kirke ,,white1 ,cabinet ,edition1 comprising1 in a very small but remarkably clear type1 as much matter as the sixty volumes of ,johnson's ,poets4 ,complete in #d ,vols41 with ,frontispieces4 #ads4 ,,cary',s ,,translation ,,of ,,dante4 ,extra cloth4 #gs4 #f;d4 ,,cattermole',s ,,evenings ,,at ,,haddon ,,hall4 #bd exquisite ,engravings on ,steel1 from ,designs by himself2 the ,letter-,press by the ,,baroness ,,de ,,calabrella4 ,post #hvo4 #gs4 #f;d4 ,,classic ,,tales2 comprising ,the ,vicar of ,wakefield1 ,elizabeth1 ,paul and ,virginia1 ,gulliver's ,travels1 ,sterne's ,sentimental ,journey1 ,sorrows of ,werter1 ,theodosius and ,constantia1 ,castle of ,otranto1 and ,rasselas4 #abmo4 #g ,portraits4 #cs4 #f;d4 ,,demosthenes4 ,translated by ,,leland4 ,portrait4 #cs4 ,,chillingworth',s ,,religion ,,of ,,protestants4 #cs4 #f;d4 ,,horace',s ,,odes ,,and ,,epodes1 translated literally and rythmically1 by the ,,rev4 ,w4 ,,sewell4 #cs4 #f;d4 ,,irving',s 7,,washington7 ,,works4 ,complete in #aj ,vols41 #a #aes41 or #cs4 #f;d4 per ,vol4 ,,joyce',s ,,scientific ,,dialogues4 ,greatly ,improved ,edition1 with ,questions1 c41 by ,,pinnock4 7,upwards of #fjj pages74 ,woodcuts4 #es4 ,,joyce',s ,,introduction ,,to ,,the ,,arts ,,and ,,sciences4 #es4 ,,lamartine',s ,,three ,,months ,,in ,,power4 ,sewed1 #bs4 ,,lamartine',s ,,poetical ,,meditations ,,and ,,religious ,,harmonies1 with ,biographical ,sketch4 ,portrait4 ,cloth1 #cs4 #f;d4 ,,lawrence',s ,,lectures ,,on ,,comparative ,,anatomy1 ,,physiology1 ,,zoology1 ,,and ,,the ,,natural ,,history ,,of ,,man4 ,front4 and ,plates4 #es4 ,,lilly',s ,,introduction ,,to ,,astrology4 ,a ,new and ,improved ,edition1 by ,,zadkiel1 with his ,grammar of ,astrology1 and ,tables of ,nativities4 #es4 ,,loudon',s 7,,mrs47 ,,entertaining ,,naturalist1 a ,popular ,description1 ,tales1 and ,anecdotes of more than ,five ,hundred ,animals1 with ,indexes of ,scientific and ,popular ,names4 ,with upwards of #ejj beautiful ,woodcuts1 by ,,bewick1 ,,harvey1 ,,whimper1 c4 ,revised and enlarged4 #gs4 #f;d4 ,,lowth',s ,,lectures ,,on ,,the ,,sacred ,,poetry ,,of ,,the ,,hebrews4 #cs4 #f;d4 ,,maxwell',s ,,victories ,,of ,,the ,,british ,,armies4 ,new ,edition1 with highly finished ,steel ,portraits1 extra gilt cloth4 #gs4 #f;d4 ,,michelet',s ,,history ,,of ,,the ,,french ,,revolution4 #ds4 ,,miller',s ,,philosophy ,,of ,,history4 ,third ,revised and ,improved ,edition1 #d ,volumes1 at #cs4 #f;d4 per ,volume4 ,,milner',s ,,history ,,of ,,the ,,church ,,of ,,christ4 #d vols4 #ads4 ,,mitford',s 7,,miss7 ,,our ,,village4 #b ,vols41 ,new ,edition1 with ,woodcuts and beautiful ,frontispieces on ,steel1 gilt cloth4 ,each ,vol4 #es4 ,,parkes' ,,elementary ,,chemistry4 ,new ,edition1 revised1 #es4 ,,robinson ,,crusoe1 including his further ,adventures1 with ,life of ,defoe1 c4 ,upwards of #fj fine ,woodcuts1 from designs by ,,harvey and ,,whimper4 #ds4 #f;d4 ,,schiller',s ,,philosophical ,,sthetic ,,letters ,,and ,,essays4 #cs4 #f;d4 ,,shakspeare',s ,,plays ,,and ,,poems1 with ,life1 by ,,chalmers4 ,in #a ,vol4 #cs4 #f;d4 ,,standard ,,library ,,cyclop,,dia ,,of ,,political1 ,,constitutional1 ,,statistical1 ,,and ,,forensic ,,knowledge4 #d ,vols4 #cs4 #f;d4 each4 ,this work contains as much as eight ordinary octavos4 ,it was first published in another shape by ,mr4 ,charles ,knight1 under the title of ,political ,dictionary1 at #a #afs4 ,the ,compiler1 ,,mr4 ,,george ,,long1 is one of the most competent ,scholars of the day4 ,also1 uniform with the ,,standard ,,library1 price #es41 ,,bohn',s ,,ecclesiastical ,,library4 #a4 ,,eusebius' ,,ecclesiastical ,,history1 ,translated from the ,greek1 with ,notes4 ,,bohn',s ,,shilling ,,series4 ,those marked 991 being ,double ,volumes1 are #as4 #f;d4 #a4 ,,emerson',s ,,representative ,,men4 #b4 ,,irving',s ,,life ,,of ,,mahomet499 #c4 ,,the ,,genuine ,,autobiography ,,of ,,benjamin ,,franklin4 #d4 ,,willis',s ,,people ,i ,,have ,,met499 #e4 ,,irving',s ,,successors ,,of ,,mahomet499 #f4---- ,,life ,,of ,,goldsmith499 #g4---- ,,sketch-,,book499 #h4---- ,,tales ,,of ,a ,,traveller499 #i4---- ,,tour ,,on ,,the ,,prairies4 #aj #aa4---- ,,conquests ,,of ,,granada ,,and ,,spain4 #b ,vols499 #ab #ac4---- ,,life ,,of ,,columbus4 #b ,vols499 #ad4---- ,,companions ,,of ,,columbus499 #ae #af4 ,,taylor',s ,,el ,,dorado2 or1 ,pictures of the ,gold ,region4 #b ,vols499 #ag4 ,,irving',s ,,adventures ,,of ,,captain ,,bonneville499 #ah4---- ,,knickerbocker499 #ai4---- ,,tales ,,of ,,the ,,alhambra499 #bj4---- ,,conquest ,,of ,,florida499 #ba4---- ,,abbotsford ,,and ,,newstead4 #bb4---- ,,salmagundi499 #bc4---- ,,bracebridge ,,hall499 #bd4---- ,,astoria 7with fine ,portrait of the ,author74 #b ,vols4 in #a4 #bs4 #be4 ,,lamartine',s ,,genevieve2 or1 ,the ,history of a ,servant ,girl4 ,translated by ,a4 ,r4 ,,scoble499 #bf4 ,,mayo',s ,,berber2 or1 ,the ,mountaineer of the ,atlas4 ,a ,tale of ,morocco4 #bg4 ,,willis',s ,,life ,,here ,,and ,,there2 or1 ,sketches of ,society and ,adventure499 #bh4 ,,guizot',s ,,life ,,of ,,monk1 with ,appendix and ,portrait499 #bi4 ,,the ,,cape ,,and ,,the ,,kaffirs3 ,a ,diary of ,five ,years' ,residence1 with ,advice to ,emigrants4 ,by ,h4 ,,ward4 ,plate and ,map of the ,seat of ,war4 #bs4 #cj4 ,,willis',s ,,hurry-,,graphs2 or1 ,sketches of ,scenery1 ,celebrities1 and ,society1 taken from ,life499 #ca4 ,,hawthorne',s ,,house ,,of ,,the ,,seven ,,gables4 ,a ,romance4 #cb4 ,,london ,,and ,,its ,,environs2 with ,historical and ,descriptive ,sketch of the ,great ,exhibition4 ,by ,,cyrus ,,redding4 ,numerous ,illustrations4 #bs4 #cc4 ,,lamartine',s ,,stonemason ,,of ,,saint ,,point499 #cd4 ,,guizot',s ,,monk',s ,,contemporaries4 ,a ,series of ,biographic ,studies on the ,english ,revolution4 ,portrait of ,edward ,lord ,clarendon4 #ce4 ,,hawthorne',s ,,twice-,,told ,,tales4 #cf4------------ ,second ,series4 #cg4---- ,,snow ,,image1 and other ,tales4 #ch4---- ,,scarlet ,,letter4 #ci4 ,,emerson',s ,,orations ,,and ,,lectures4 ,also1 uniform with the ,,standard ,,library1 #es4 7except ,thucydides1 schylus1 ,virgil1 ,horace1 and ,cicero's ,offices1 which are #cs4 #f;d4 each71 ,,bohn',s ,,classical ,,library4 ,a ,,series ,,of ,,literal ,,prose ,,translations ,,of ,,the ,,greek ,,and ,,latin ,,classics1 ,,with ,,notes4 #a4 ,,herodotus4 ,by the ,,rev4 ,,henry ,,cary1 ,m4,a4 ,index1 and ,frontispiece4 #b #c4 ,,thucydides4 ,by the ,,rev4 ,h4 ,,dale4 ,in #b ,vols4 7#cs4 #f;d4 each74 #d4 ,,plato4 ,vol4 ,i4 ,by ,,cary4 ,the ,apology of ,socrates1 ,crito1 ,phdo1 ,gorgias1 ,protagotas1 ,phdrus1 ,thetetus1 ,euthyphron1 ,lysis4 #e4 ,,livy',s ,,history ,,of ,,rome4 ,vol ,i41 ,books #a to #h4 #f4 ,,plato4 ,vol4 ,,ii4 ,by ,,davis4 ,the ,republic1 ,timus1 and ,critias4 #g4 ,,livy',s ,,history ,,of ,,rome4 ,vol4 ,,ii41 ,books #i to #bf4 #h4 ,,sophocles4 ,the ,oxford ,translation1 revised4 #i4 ,,schylus4 ,by an ,,oxonian4 7,price #cs4 #f;d47 #aj4 ,,aristotle',s ,,rhetoric ,,and ,,poetic4 ,with ,examination ,questions4 #aa4 ,,livy',s ,,history ,,of ,,rome4 ,vol4 ,,iii41 ,books #bg to #cf4 #ab #ad4 ,,euripides4 ,from the ,text of ,dindorf4 ,in #b ,vols4 #ac4 ,,virgil4 ,by ,,davidson4 ,new ,edition1 ,revised4 7,price #cs4 #f;d47 #ae4 ,,horace4 ,by ,,smart4 ,new ,edition1 ,revised4 7,price #cs4 #f;d47 #af4 ,,aristotle',s ,,ethics4 ,by ,,prof4 ,r4 ,w4 ,,browne1 of ,king's ,college4 #ag4 ,,cicero',s ,,offices4 ,old ,age1 ,friendship1 ,scipio's ,dream1 ,paradoxes1 c4 #ah4 ,,plato4 ,vol4 ,,iii4 ,by ,g4 ,,burges1 ,m4,a4 ,euthydemus1 ,symposium1 ,sophistes1 ,politicus1 ,laches1 ,parmenides1 ,cratylus1 and ,meno4 #ai4 ,,livy',s ,,history ,,of ,,rome4 ,vol4 ,,iv4 7which completes the work74 #bj4 ,c,,sar ,,and ,,hirtius4 ,with ,index4 #ba4 ,,homer',s ,,iliad4 ,frontispiece4 #bb4 ,,homer',s ,,odyssey1 ,,hymns1 ,,epigrams1 ,,and ,,battle ,,of ,,the ,,frogs ,,and ,,mice4 #bc4 ,,plato4 ,vol4 ,,iv4 ,by ,g4 ,,burges1 ,m4,a4 ,philebus1 ,charmides1 ,laches1 ,the ,two ,alcibiades1 and ,ten other ,dialogues4 #bd1 #be1 #cb4 ,,ovid4 ,by ,h4 ,t4 ,,riley1 ,b4,a4 ,complete in #c ,vols4 ,frontispieces4 #bf4 ,,lucretius4 ,by the ,,rev4 ,j4 ,s4 ,,watson4 ,with the ,metrical ,version of ,j4 ,m4 ,,good4 #bg1 #cj1 #ca1 #cd4 ,,cicero',s ,,orations4 ,by ,c4 ,d4 ,,yonge4 ,complete in #d ,vols 7,vol4 #d contains also the ,rhetorical ,pieces47 #bh4 ,,pindar4 ,by ,,dawson ,w4 ,,turner4 ,with the ,metrical ,version of ,,moore4 ,front4 #bi4 ,,plato4 ,vol4 ,v4 ,by ,g4 ,,burges1 ,m4,a4 ,the ,laws4 #cc4 ,,the ,,comedies ,,of ,,plautus4 ,by ,h4 ,t4 ,,riley1 ,b4,a4 ,in #b ,vols4 ,vol4 ,i4 #ce4 ,,juvenal1 ,,persius1 c4 ,by the ,,rev4 ,l4 ,,evans1 ,m4,a4 ,with the ,metrical ,version of ,,gifford4 ,frontispiece4 ,also1 uniform with the ,,standard ,,library1 at #es4 per volume1 ,,bohn',s ,,illustrated ,,library4 #a to #h4 ,,lodge',s ,,portraits ,,of ,,illustrious ,,personages ,,of ,,great ,,britain4 #h ,vols4 post #hvo4 #bdj ,portraits4 #i4 ,,cruikshank',s ,,three ,,courses ,,and ,,dessert1 with #ej ,illustrations4 #aj4 ,,pickering',s ,,races ,,of ,,man1 with numerous ,portraits 7or ,coloured #gs4 #f;d47 #aa4 ,,kitto',s ,,scripture ,,lands1 ,,and ,,biblical ,,atlas1 with #bd ,maps1 7or ,coloured1 #gs4 #f;d47 #ab4 ,,white',s ,,natural ,,history ,,of ,,selborne1 with ,notes by ,,sir ,,wm4 ,,jardine and others1 edited1 with large additions1 by ,,ed4 ,,jesse1 ,esq4 ,with #dj highly-finished ,wood ,engravings 7,coloured1 #gs4 #f;d47 #ac4 ,,didron',s ,,christian ,,iconography1 with #aej beautiful ,engravings4 ,in #b ,vols4 ,vol4 ,i4 #ad4 ,,redding ,,on ,,wines4 ,new and ,revised ,edition1 with #bj beautiful ,woodcuts4 #ae #af4 ,,allen',s ,,battles ,,of ,,the ,,british ,,navy4 ,new ,edition4 ,enlarged by the ,author4 ,numerous fine ,portraits on ,steel4 #b ,vols4 #ag #ah4 ,,rome ,,in ,,the ,,nineteenth ,,century4 ,fifth ,edition1 in #b ,vols41 with #cd fine ,steel ,engravings1 and ,index4 ,also1 uniform with the ,,standard ,,library1 price #es41 ,,bohn',s ,,antiquarian ,,library4 #a4 ,,bede',s ,,ecclesiastical ,,history1 ,,the ,,anglo-,,saxon ,,chronicle4 #b4 ,,mallet',s ,,northern ,,antiquities4 ,by ,,bishop ,,percy4 ,with ,abstract of the ,eyrbiggia ,saga1 by ,,sir ,,walter ,,scott4 ,edited by ,j4 ,a4 ,,blackwell4 #c4 ,,william ,,of ,,malmesbury',s ,,chronicle ,,of ,,the ,,kings ,,of ,,england4 #d4 ,,six ,,old ,,english ,,chronicles3 viz41 ,asser's ,life of ,alfred2 the ,chronicles of ,ethelwerd1 ,gildas1 ,nennius1 ,geoffry of ,monmouth1 and ,richard of ,cirencester4 #e4 ,,ellis',s ,,early ,,english ,,metrical ,,romances4 ,revised by ,j4 ,,orchard ,,halliwell4 ,complete in one vol41 with ,illuminated ,frontispiece4 #f4 ,,chronicles ,,of ,,the ,,crusaders3 ,richard of ,devizes1 ,geoffrey de ,vinsauf1 ,lord de ,joinville4 ,complete in #a volume1 with ,frontispiece4 #g4 ,,early ,,travels ,,in ,,palestine4 ,willibald1 ,swulf1 ,benjamin of ,tudela1 ,mandeville1 ,la ,brocquiere1 and ,maundrell4 ,in one volume4 ,with ,map4 #h1 #aj1 #ab4 ,,brand',s ,,popular ,,antiquities ,,of ,,great ,,britain4 ,by ,,sir ,,henry ,,ellis4 ,in #c ,vols4 #i #aa4 ,,roger ,,of ,,wendover',s ,,flowers ,,of ,,history 7formerly ascribed to ,matthew ,paris47 ,in #b ,vols4 #ac4 ,,keightley',s ,,fairy ,,mythology4 ,enlarged4 ,frontispiece by ,,cruikshank4 #ad1 #ae1 #af4 ,,sir ,,thomas ,,browne',s ,,works4 ,edited by ,,simon ,,wilkin4 ,portrait4 ,in #c ,vols4 ,with ,index4 ,,bohn',s ,,miniature ,,library4 ,foolscap #abmo4 elegantly bound in morocco cloth4 ,,barbauld ,,and ,,aikin',s ,,evenings ,,at ,,home4 ,frontisps4 #cs4 ,,bourrienne',s ,,memoirs ,,of ,,napoleon1 fine ,portrait and ,frontisp4 #cs4 #f;d4 ,,bunyan',s ,,pilgrim',s ,,progress4 ,with a ,life and ,notes by ,,scott1 containing all in ,southey's ,edition4 #be fine ,woodcuts1 by ,,harvey1 ,frontisp4 c4 #cs4 #f;d4 ---- ,,cheever',s ,,lectures ,,on1 ,frontisp4 #bs4 #f;d4 ,,byron',s ,,poetical ,,works1 in #a thick ,volume1 including several suppressed ,poems not included in other editions4 ,beautiful ,frontispiece4 #cs4 #f;d4 ---- ,,don ,,juan1 complete4 ,frontispieces4 #bs4 #f;d4 ,,coleridge',s ,,select ,,poetical ,,works4 #bs4 ,,cowper',s ,,poetical ,,works1 with ,life by ,,southey1 including all the copyright ,poems 7#gjj pages74 ,beautiful ,frontispieces after ,,harvey1 by ,,goodall4 #cs4 #f;d4 ,,encyclop,,dia ,,of ,,manners ,,and ,,etiquette1 comprising an improved edition of ,chesterfield's ,advice to his ,son on ,men and ,manners4 #bs4 ,,heber',s 7,,bp47 ,,mrs4 ,,hemans' ,,poetical ,,works4 #c ,vols4 in #a4 ,frontisp4 #cs4 ,,herrick',s ,,poetical ,,works1 complete4 ,frontispiece4 #cs4 ,,joe ,,miller',s ,,jest ,,book4 ,frontispiece4 #cs4 ,,longfellow',s ,,poetical ,,works1 viz4--,voices of the ,night--,evangeline--,seaside and ,fireside--,spanish ,students--,translations4 ,portrait and ,frontisp4 #cs4 #f;d4 ---- ,,prose ,,works1 viz4--,outre-,mer--,hyperion--,kavanagh4 #cs4 #f;d4 ,,milton',s ,,poetical ,,works1 with ,life and ,notes by ,,dr4 ,,stebbing2 and ,dr4 ,channing's ,essay on ,milton4 ,frontispiece4 #cs4 #f;d4 ,,ossian',s ,,poems1 with ,dissertations by ,,macpherson and ,dr4 ,blair4 ,frontisp4 #cs4 ,,pope',s ,,homer',s ,,iliad4 ,essay on ,homer4 ,notes and ,essays4 ,frontispiece4 #cs4 ---- ,,odyssey1 7uniform74 ,frontispiece4 #cs4 ,,scott',s ,,poetical ,,works1 and ,life1 in one volume4 ,port4 and ,frontisp4 #cs4 #f;d4 ,,sturm',s ,,reflections ,,on ,,the ,,works ,,of ,,god4 ,frontisp4 #bs4 ,,thompson',s ,,seasons4 ,with his ,castle of ,indolence1 #d beautiful ,woodcuts4 #bs4 ,,vathek1 ,,and ,,the ,,amber ,,witch4 #b vols4 in #a4 #cs4 ,,transcriber',s ,,note4 ,archaic1 obsolete1 unusual and inconsistent spellings have been maintained as in the original book4 ,obvious errors have been fixed as detailed below4 ,some entries in the index were out of alphabetical order in the original book4 ,they have been moved without noting them in the details below4 ,the totals in the various tables are not equal to the sum of the column above them4 ,i assume this is due to round off error1 or details in the original data which are not represented here4 ,no attempt has been made to correct these totals4 ,in the original book1 half of the publisher's catalogue 7,bohn's ,books7 was in the beginnig of the book4 ,it was moved to immediately precede the other half of the catalogue at the end of the book4 ,preface1 ,contents1 ,introduction1 ,index1 ,bohn's ,books and ,transcriber's ,note have been added to the table of contents4 ,only the chapters of the book were in the table of contents in the original book4 ,the title ,bohn's ,books was inserted into the beginning of the publisher's book catalogue4 ,in the table below1 the first line shows the text in this ebook1 the second line shows the text in the original book4 ,page vii43 conditions of ,matter--,diamagnetism1 c4 #bce ,originally3 conditions of ,matter--,dia-,magnetism1 c4 #bce ,page viii43 ,time1 an element in ,nature's ,operations--,geological ,originally3 ,time1 an element in ,nature's ,operations,geological ,page viii43 ,progress of ,matter towards ,organization ,originally3 ,progress of ,matter rowards ,organization ,page xii43 of external nature1 evoked beautiful spiritualizations ,originally3 of external nature1 evoked beautiful spirtualizations ,footnote #a3 ,boscovich regarded the constitution of matter differently ,originally3 ,boscovitch regarded the constitution of matter differently ,footnote #a3 full explanation of the theory of ,boscovich47 ,originally3 full explanation of the theory of ,boscovitch47 ,page #h3 ,the views of metaphysicians regarding motion involve ,originally3 ,the views of metaphyscians regarding motion involve ,page #ad3 tremulous gyration upon the deck of a vast arial ship ,originally3 tremulous gyration upon the deck of a vast aerial ship ,page #bg3 agent of organisation and all manifestations of beauty8 ,originally3 agent of organisation and all manifestatious of beauty8 ,footnote #ah3 fixes1 est dtermine par ce qui prcde entre certaines ,originally3 fixes1 est determine par ce qui prcde entre certaines ,footnote #ah3 est le groupe central de l'ensemble du systme ,originally3 est le groupe central l'ensemble du systme ,footnote #bd3 into a single mass at the bottom of the flask under ,originally3 into a single mass at the bottom of the flask unde ,page #db3 with which the particles combined1 from interstices1 ,originally3 with which the particles combined1 from insterstices1 ,page #de3 bromine1 c41 are the results of different allotropic ,originally3 bromime1 c41 are the results of different allotropic ,page #df3 which1--from the imperfections of science1--resisting ,originally3 which1--from the imperfectious of science1--resisting ,page #df3 ,the experiments of ,faraday and of ,plcker prove ,originally3 ,the experiments of ,faraday and of ,plucker prove ,footnote #be3 ,young's ,natural ,philosophy2 ed4 by ,rev4 ,p4 ,kelland4 ,originally3 ,young's ,natural ,philosophy2 ed4 by ,rev4 ,p4 ,lelland4 ,footnote #ce3 ,hence the origin of compound and visible bodies2 hence ,originally3 ,hence the origin of compouud and visible bodies2 hence ,page #ej3 her operations1 but the very processes themselves4 ,originally3 her operations1 but the very processes themselvss4 ,paqe #ei3 combination appears to the eye in no respect different ,originally3 combinatiou appears to the eye in no respect different ,page #fa3 ,those fissures formed by the first system of crystalline ,originally3 ,those fissures formed by the first sytsem of crystalline ,page #fh3 luminous power are sufficiently striking to convince us ,originally3 luminous power are sufficienlty striking to convince us ,page #aji3 of temperature is experienced4#gi ,professor ,plcker1 of ,originally3 of temperature is experienced4#gi ,professor ,plucker1 of ,footnote #ee3 this motion4 ,he was followed by ,musschenbroek1 and then ,originally3 this motion4 ,he was followed by ,muschenbroek1 and then ,footnote #fa3 regarding the internal temperature of the ,earth3 by ,originally3 regarding the internal temperature of tha ,earth3 by ,footnote #gh3 en vertu de l'tat sphrodal dans un creuset ,originally3 en vertu de l'tat sphrodal dans un creuset ,page #aba3 ,fraunhofer1 ,herschel1 ,brewster1 and others1 but proceed ,originally3 ,frauenhofer1 ,herschel1 ,brewster1 and others1 but proceed ,page #abc3 between charcoal points at the poles of a powerful voltaic ,originally3 between charcoal points a the poles of a powerful voltaic ,page #abi3 of quinine1 and the fluor spar1 we obtain the same results ,originally3 of quinine1 and the flour spar1 we obtain the same results ,page #adj3 the first instance1 by ,erasmus ,bartholin1 in ,iceland-spar1 ,originally3 the first instance1 by ,erasmus ,bartolin1 in ,iceland-spar1 ,page #ade3 from what has been already stated1 that some ,originally3 from what has beeen already stated1 that some ,page #aec3 to prove that light is absolutely necessary to ,originally3 to prove that light is absolutely neccessary to ,page #aei3 of light behind them4#aac ,by microscopic examination ,originally3 of light behind them4#aac ,by miscroscopic examination ,page #aei3 ,benvenuto ,cellini gave a curious account of a carbuncle ,originally3 ,benvenuto ,cellini give a curious account of a carbuncle ,page #afj3 near a fire4 ,from this it may be inferred that the ,originally3 near a a fire4 ,from this it may be infered that the ,footnote #hh3 ,brande's ,manual of ,chemistry2 or1 indeed1 any work ,originally3 ,brande's ,mannal of ,chemistry2 or1 indeed1 any work ,footnote #id3 ,schouw1 ,grundzge der ,pflanzengeographie4 ,also his ,originally3 ,schouw1 ,grundzge der ,pflanzengeographie4 ,also his ,footnote #ie3 ,fraunhofer's measure of illuminating power is as ,originally3 ,frauenhofer's measure of illuminating power is as ,footnote #ii3 ,sur une ,proprit de la ,lumire ,rflchie3 ,mmoires ,originally3 ,sur une ,proprit de la ,lumire ,rflchie3 ,memoires ,page #agf3 the strongest sunlight which has passed through ,originally3 the strongest sun-light which has passed through ,page #agi3 productions of the photographer as on those of the ,originally3 productions of the photograper as on those of the ,page #ahj3 preserve the lineaments of those who have benefited ,originally3 preserve the lineaments of those who have benefitted ,page #ahe3 line1 over which no action takes place1 is preserved at ,originally3 line1 over which no action takes plates1 is preserved at ,page #ahe3 presented to us by a circular body3 calorific action seems ,originally3 present to us by a circular body3 calorific action seems ,page #ahh3 piece of wood is used instead of a metal1 there will1 by ,originally3 piece of wood is used instead of a medal1 there will1 by ,footnote #abf3 dans la vgtation3 by ,senebier2 ,genve et ,paris1 #aghh ,originally3 dans la vgetation3 by ,senebier2 ,genve et ,paris1 #aghh ,page #aih3 ,leyden phial1--so called from its inventor1 ,musschenbroek1 ,originally3 ,leyden phial1--so called from its inventor1 ,muschenbrock1 ,page #bai3 may be made a measurer of nervous irritability4#aed ,there ,originally3 may be made a measurer of nervous iritability4#aed ,there ,footnote #ada3 ,trait ,exprimental de l'lectricit et du ,magntisme3 ,originally3 ,trait ,exprimental de l',electricit et du ,magntisme3 ,footnote #adf3 ,trait ,exprimental de l'lectricit et du ,magntisme4 ,originally3 ,trait ,exprimental de l',electricit et du ,magntisme ,footnote #afj3 where the cobalt was discovered between two portions of ,originally3 where the cobalt was discovered betweed two portions of ,page #bce3 ,storms--,magnetic conditions of ,matter--,diamagnetism1 ,originally3 ,storms--,magnetic conditions of ,matter--,dia-,magnetism1 ,page #bcf3 ,magntum1 quia sit patriis in finibus ortus4 ,originally3 ,magntum1 buia sit patriis in finibus ortus4 ,page #bea3 conditions of change in this our earth3 an element to ,originally3 conditions of change in this our earth3 an elemeut to ,page #beg3 ,wiedemann1 by employing a fine point through which ,originally3 ,wiedmann1 by employing a fine point through which ,page #beh3 than in any other4 ,m4 ,wiedemann comes to the conclusion ,originally3 than in any other4 ,m4 ,wiedmann comes to the conclusion ,page #bfj3 salt1 the protosulphate1 ordinarily crystallizes so that ,originally3 salt1 the proto-sulphate1 ordinarily crystallizes so that ,footnote #agf3 ,humboldt3 ,expos des ,variations ,magntiques4 ,originally3 ,humboldt3 ,expos des ,variations ,magnetiques4 ,footnote #ahh3 ,electro-,magnetic ,influence1 by ,professor ,zantedeschi4 ,originally3 ,electro-,magnetic ,influence1 by ,professor ,zandeteschi4 ,footnote #aij3 detailed account of the experiments of ,faraday1 ,plcker1 ,originally3 detailed account of the experiments of ,faraday1 ,plucker1 ,page #bgf3 light determine these changes8 ,it is evident1 although ,originally3 light determine these change8 ,it is evident1 although ,page #bha3 chemical change4 ,dbereiner next discovered that ,originally3 chemical change4 ,dbereiner next discovered that ,page #bhb3 a fearful example in the progress of ,asiatic ,originally3 a fearful example in the progress of ,asatic ,page #cjj3 as being either peroxide of hydrogen1 or an allotropic ,originally3 as being either per-oxide of hydrogen1 or an allotropic ,page #cjd3 the gas which we employ so advantageously for illumination ,originally3 the gas which we emply so advantageously for illumination ,page #cjf3 increasing1--true combustion takes place4 ,in this way ,originally3 increasing1--true combustion takes plaee4 ,in this way ,page #cjf3 sawdust1 c41 frequently ignite2 and to such an ,originally3 saw-dust1 c41 frequently ignite2 and to such an ,page #caf3 ,mr4 ,darwin remarks1 that if the immense sea-weeds of ,originally3 ,mr4 ,darwin remarks1 that if the immense seaweeds of ,page #cag3 ,when ,shakespeare made his charming ,ariel sing-- ,originally3 ,when ,shakspeare made his charming ,ariel sing-- ,footnote #bab3 7,redundant line removed before item #b in table47 ,originally3 ,according to one view1 ,according to the other view1 ,page #ccd3 speculation1 which may have occasional marks of ingenuity1 ,originally3 speculation1 whieh may have occasional marks of ingenuity1 ,page #ccg3 origin1 the rational inference is against the speculation2 ,originally3 orgin1 the rational inference is against the speculation2 ,page #cgj3 capsule of nigella orientalis consists of pods assembled ,originally3 capsule of nigilla orientalis consists of pods assembled ,page #cgj3 a centre1 and partially united2 in nigella damascena ,originally3 a centre1 and partially united2 in nigilla damascena ,page #cii3 whose minds are sceptical upon any development of the ,originally3 whose mind are sceptical upon any development of the ,page #djf3 evidence of a beautiful adjustment of the balance of ,originally3 evidence of a beautifnl adjustment of the balance of ,page #djh3 ,let but a slight disturbance occasion a vibration ,originally3 ,let but a slight disturbance occcasion a vibration ,page #dji3 ,a cheerless philosophy1 derived from the transcendentalism ,originally3 ,a cheerless philosophy1 derived from the transendentalism ,page #daj3 which are allowed the privilege of tracing out its ,originally3 which are alowed the privilege of tracing out its ,page #dac3 ,areal currents dependent on heat1 #hj4 ,originally3 real currents dependent on heat1 #hj4 ,page #dac3 ,animal electricity1 #baa1 #cib4 ,originally3 ,magnetic electricity1 #baa1 #cib4 ,page #dac3 ,bartholin on ,iceland spar1 #adj4 ,originally3 ,bartolin on ,iceland spar1 #adj4 ,page #dad3 ,cagniard de la ,tour state1 #ajf4 ,originally3 ,caignard de la ,tour state1 #ajf4 ,page #dae3 ,dbereiner's lamp1 #bha4 ,originally3 ,doebereiner's lamp1 #bha4 ,page #dae3 ,eye1 mechanism of1 #adi4 ,originally3 ,eye1 mechanism of1 #dia4 ,page #daf3 ---- on diamagnetism1 #bed4 ,originally3 ---- on dia-magnetism1 #bed4 ,page #dah3 ,musschenbroek of ,leyden1 #aih4 ,originally3 ,muschenbrock of ,leyden1 #aih4 ,page #dba3 ,wiedemann on electrical vibrations1 #beg4 ,originally3 ,wiedman on electrical vibrations1 #beg4 ,bohn's ,books3 ,,loudon',s 7,,mrs47 ,,entertaining ,,naturalist1 ,originally3 ,,loudon',s 7,,mrs47 ,,entertaing ,,naturalist1 ,bohn's ,books3 ,indexes of ,scientific and ,popular ,names4 ,with ,originally3 ,indexes of ,scientific and and ,popular ,names4 ,with ,bohn's ,books3 #ah4 ,,plato4 ,vol4 ,,iii4 ,by ,g4 ,,burges1 ,m4,a4 ,euthydemus1 ,originally3 #h4 ,,plato4 ,vol4 ,,iii4 ,by ,g4 ,,burges1 ,m4,a4 ,euthydemus1 ,bohn's ,books3 #ce4 ,,juvenal1 ,,persius1 c4 ,by the ,,rev4 ,l4 ,,evans1 ,m4,a4 ,originally3 #cd4 ,,juvenal1 ,,persius1 c4 ,by the ,,rev4 ,l4 ,,evans1 ,m4,a4