,,the ,,romance ,,of ,,science ,,the ,,machinery ,,of ,,the ,,universe ,,mechanical ,,conceptions ,,of ,,physical ,,phenomena ,,by ,a4 ,e4 ,,dolbear1 ,a4,b41 ,a4,m41 ,m4,e41 ,,ph4,d4 ,,professor ,,of ,,physics ,,and ,,astronomy1 ,,tufts ,,college1 ,,mass4 ,,published ,,under ,,general ,,literature ,,committee4 ,,london3 ,,society ,,for ,,promoting ,,christian ,,knowledge1 ,,northumberland ,,avenue1 ,w4,c42 #dc1 ,,queen ,,victoria ,,street1 ,e4,c4 ,,brighton3 #abi1 ,,north ,,street4 ,,new ,,york3 ,e4 ,j4 ,b4 ,,young ,,co4 #ahig4 ,,preface ,for thirty years or more the expressions ,correlation of the ,physical ,forces and ,the ,conservation of ,energy have been common1 yet few persons have taken the necessary pains to think out clearly what mechanical changes take place when one form of energy is transformed into another4 ,since ,tyndall gave us his book called ,heat as a ,mode of ,motion neither lecturers nor text-books have attempted to explain how all phenomena are the necessary outcome of the various forms of motion4 ,in general1 phenomena have been attributed to forces--a metaphysical term1 which explains nothing and is merely a stop-gap1 and is really not at all needful in these days1 seeing that transformable modes of motion1 easily perceived and understood1 may be substituted in all cases for forces4 ,in ,december #ahie the author gave a lecture before the ,franklin ,institute of ,philadelphia1 on ,mechanical ,conceptions of ,electrical ,phenomena1 in which he undertook to make clear what happens when electrical phenomena appear4 ,the publication of this lecture in ,the ,journal of the ,franklin ,institute and in ,nature brought an urgent request that it should be enlarged somewhat and published in a form more convenient for the public4 ,the enlargement consists in the addition of a chapter on the ,contrasted ,properties of ,matter and the ,ether1 a chapter containing something which the author believes to be of philosophical importance in these days when electricity is so generally described as a phenomenon of the ether4 ,a4 ,e4 ,,dolbear4 ,,table ,,of ,,contents ,,chapter ,i ,ideas of phenomena ancient and modern1 metaphysical and mechanical--,imponderables--,forces1 invented and discarded--,explanations--,energy1 its factors1 ,kinetic and ,potential--,motions1 kinds and transformations of--,mechanical1 molecular1 and atomic--,invention of ,ethers1 ,faraday's conceptions p4 #g ,,chapter ,,ii ,properties of ,matter and ,ether compared--,discontinuity versus ,continuity--,size of atoms--,astronomical distances--,number of atoms in the universe--,ether unlimited--,kinds of ,matter1 permanent qualities of--,atomic structure2 vortex-rings1 their properties--,ether structureless--,matter gravitative1 ,ether not--,friction in ,matter1 ,ether frictionless--,chemical properties--,energy in ,matter and in ,ether--,matter as a transformer of ,energy--,elasticity--,vibratory rates and waves--,density--,heat--,indestructibili ty of ,matter--,inertia in ,matter and in ,ether--,matter not inert--,magnetism and ,ether waves--,states of ,matter--,cohesion and chemism affected by temperature--,shearing stress in ,solids and in ,ether--,ether pressure--,sensation dependent upon ,matter--,nervous system not affected by ,ether states--,other stresses in ,ether--,transformations of ,motion--,terminology p4 #bd ,,chapter ,,iii ,antecedents of ,electricity--,nature of what is transformed--,series of transformations for the production of light--,positive and negative ,electricity--,positive and negative twists--,rotations about a wire--,rotation of an arc--,ether a non-conductor--,electro-magnetic waves--,induction and inductive action--,ether stress and atomic position--,nature of an electric current--,electricity a condition1 not an entity p4 #id ,,chapter ,i ,ideas of phenomena ancient and modern1 metaphysical and mechanical--,imponderables--,forces1 invented and discarded--,explanations--,energy1 its factors1 ,kinetic and ,potential--,motions1 kinds and transformations of--,mechanical1 molecular1 and atomic--,invention of ,ethers1 ,faraday's conceptions4 ',and now we might add something concerning a most subtle spirit which pervades and lies hid in all gross bodies1 by the force and action of which spirit the particles of bodies attract each other at near distances1 and cohere if contiguous1 and electric bodies operate at greater distances1 as well repelling as attracting neighbouring corpuscles1 and light is emitted1 reflected1 inflected1 and heats bodies1 and all sensation is excited1 and members of animal bodies move at the command of the will4'--,,newton1 ,principia4 ,in ,newton's day the whole field of nature was practically lying fallow4 ,no fundamental principles were known until the law of gravitation was discovered4 ,this law was behind all the work of ,copernicus1 ,kepler1 and ,galileo1 and what they had done needed interpretation4 ,it was quite natural that the most obvious and mechanical phenomena should first be reduced1 and so the ,principia was concerned with mechanical principles applied to astronomical problems4 ,to us1 who have grown up familiar with the principles and conceptions underlying them1 all varieties of mechanical phenomena seem so obvious1 that it is difficult for us to understand how any one could be obtuse to them2 but the records of ,newton's time1 and immediately after this1 show that they were not so easy of apprehension4 ,it may be remembered that they were not adopted in ,france till long after ,newton's day4 ,in spite of what is thought to be reasonable1 it really requires something more than complete demonstration to convince most of us of the truth of an idea1 should the truth happen to be of a kind not familiar1 or should it chance to be opposed to our more or less well-defined notions of what it is or ought to be4 ,if those who labour for and attain what they think to be the truth about any matter1 were a little better informed concerning mental processes and the conditions under which ideas grow and displace others1 they would be more patient with mankind2 teachers of every rank might then discover that what is often called stupidity may be nothing else than mental inertia1 which can no more be made active by simply willing than can the movement of a cannon ball by a like effort4 ,we grow into our beliefs and opinions upon all matters1 and scientific ideas are no exceptions4 ,whewell1 in his ,history of the ,inductive ,sciences1 says that the ,greeks made no headway in physical science because they lacked appropriate ideas4 ,the evidence is overwhelming that they were as observing1 as acute1 as reasonable as any who live to-day4 ,with this view1 it would appear that the great discoverers must have been men who started out with appropriate ideas3 were looking for what they found4 ,if1 then1 one reflects upon the exceeding great difficulty there is in discovering one new truth1 and the immense amount of work needed to disentangle it1 it would appear as if even the most successful have but indistinct ideas of what is really appropriate1 and that their mechanical conceptions become clarified by doing their work4 ,this is not always the fact4 ,in the statement of ,newton quoted at the head of this chapter1 he speaks of a spirit which lies hid in all gross bodies1 etc41 by means of which all kinds of phenomena are to be explained2 but he deliberately abandons that idea when he comes to the study of light1 for he assumes the existence and activity of light corpuscles1 for which he has no experimental evidence2 and the probability is that he did this because the latter conception was one which he could handle mathematically1 while he saw no way for thus dealing with the other4 ,his mechanical instincts were more to be trusted than his carefully calculated results2 for1 as all know1 what he called spirits1 is what to-day we call the ether1 and the corpuscular theory of light has now no more than a historic interest4 ,the corpuscular theory was a mechanical conception1 but each such corpuscle was ideally endowed with qualities which were out of all relation with the ordinary matter with which it was classed4 ,until the middle of the present century the reigning physical philosophy held to the existence of what were called imponderables4 ,the phenomena of heat were explained as due to an imponderable substance called caloric1 which ordinary matter could absorb and emit4 ,a hot body was one which had absorbed an imponderable substance4 ,it was1 therefore1 no heavier than before1 but it possessed ability to do work proportional to the amount absorbed4 ,carnot's ideal engine was described by him in terms that imply the materiality of heat4 ,light was another imponderable substance1 the existence of which was maintained by ,sir ,david ,brewster as long as he lived4 ,electricity and magnetism were imponderable fluids1 which1 when allied with ordinary matter1 endowed the latter with their peculiar qualities4 ,the conceptions in each case were properly mechanical ones part 7but not all7 of the time2 for when the immaterial substances were dissociated from matter1 where they had manifested themselves1 no one concerned himself to inquire as to their whereabouts4 ,they were simply off duty1 but could be summoned1 like the genii in the story of ,aladdin's ,lamp4 ,now1 a mechanical conception of any phenomenon1 or a mechanical explanation of any kind of action1 must be mechanical all the time1 in the antecedents as well as the consequents4 ,nothing else will do except a miracle4 ,during the fifty years1 from about #ahbj to #ahgj1 a somewhat different kind of explanation of physical events grew up4 ,the interest that was aroused by the discoveries in all the fields of physical science--in heat1 electricity1 magnetism and chemistry--by ,faraday1 ,joule1 ,helmholtz1 and others1 compelled a change of conceptions2 for it was noticed that each special kind of phenomenon was preceded by some other definite and known kind2 as1 for instance1 that chemical action preceded electrical currents1 that mechanical or electrical activity resulted from changing magnetism1 and so on4 ,as each kind of action was believed to be due to a special force1 there were invented such terms as mechanical force1 electrical force1 magnetic1 chemical and vital forces1 and these were discovered to be convertible into one another1 and the doctrine of the correlation of the physical forces became a common expression in philosophies of all sorts4 ,by convertible into one another1 was meant1 that whenever any given force appeared1 it was at the expense of some other force2 thus1 in a battery chemical force was changed into electrical force2 in a magnet1 electrical force was changed into magnetic force1 and so on4 ,the idea here was the transformation of forces1 and forces were not so clearly defined that one could have a mechanical idea of just what had happened4 ,that part of the philosophy was no clearer than that of the imponderables1 which had largely dropped out of mind4 ,the terminology represented an advance in knowledge1 but was lacking in lucidity1 for no one knew what a force of any kind was4 ,the first to discover this and to repudiate the prevailing terminology were the physiologists1 who early announced their disbelief in a vital force1 and their belief that all physiological activities were of purely physical and chemical origin1 and that there was no need to assume any such thing as a vital force4 ,then came the discovery that chemical force1 or affinity1 had only an adventitious existence1 and that1 at absolute zero1 there was no such activity4 ,the discovery of1 or rather the appreciation of1 what is implied by the term absolute zero1 and especially of the nature of heat itself1 as expressed in the statement that heat is a mode of motion1 dismissed another of the so-called forces as being a metaphysical agency having no real existence1 though standing for phenomena needing further attention and explanation2 and by explanation is meant the presentation of the mechanical antecedents for a phenomenon1 in so complete a way that no supplementary or unknown factors are necessary4 ,the train moves because the engine pulls it2 the engine pulls because the steam pushes it4 ,there is no more necessity for assuming a steam force between the steam and the engine1 than for assuming an engine force between the engine and the train4 ,all the processes are mechanical1 and have to do only with ordinary matter and its conditions1 from the coal-pile to the moving freight1 though there are many transformations of the forms of motion and of energy between the two extremes4 ,during the past thirty years there has come into common use another term1 unknown in any technical sense before that time1 namely1 energy4 ,what was once called the conservation of force is now called the conservation of energy1 and we now often hear of forms of energy4 ,thus1 heat is said to be a form of energy1 and the forms of energy are convertible into one another1 as the so-called forces were formerly supposed to be transformable into one another4 ,we are asked to consider gravitative energy1 heat energy1 mechanical energy1 chemical energy1 and electrical energy4 ,when we inquire what is meant by energy1 we are informed that it means ability to do work1 and that work is measurable as a pressure into a distance1 and is specified as foot-pounds4 ,a mass of matter moves because energy has been spent upon it1 and has acquired energy equal to the work done on it1 and this is believed to hold true1 no matter what the kind of energy was that moved it4 ,if a body moves1 it moves because another body has exerted pressure upon it1 and its energy is called kinetic energy2 but a body may be subject to pressure and not move appreciably1 and then the body is said to possess potential energy4 ,thus1 a bent spring and a raised weight are said to possess potential energy4 ,in either case1 an energized body receives its energy by pressure1 and has ability to produce pressure on another body4 ,whether or not it does work on another body depends on the rigidity of the body it acts upon4 ,in any case1 it is simply a mechanical action--body ,a pushes upon body ,b 7,fig4 #a74 ,there is no need to assume anything more mysterious than mechanical action4 ,whether body ,b moves this way or that depends upon the direction of the push1 the point of its application4 ,whether the body be a mass as large as the earth or as small as a molecule1 makes no difference in that particular4 ,suppose1 then1 that a 7,fig4 #b7 spends its energy on b1 b on c1 c on d1 and so on4 ,the energy of a gives translatory motion to b1 b sets c vibrating1 and c makes d spin on some axis4 ,each of these has had energy spent on it1 and each has some form of energy different from the other1 but no new factor has been introduced between a and d1 and the only factor that has gone from a to d has been motion--motion that has had its direction and quality changed1 but not its nature4 ,if we agree that energy is neither created nor annihilated1 by any physical process1 and if we assume that a gave to b all its energy1 that is1 all its motion2 that b likewise gave its all to c1 and so on2 then the succession of phenomena from a to d has been simply the transference of a definite amount of motion1 and therefore of energy1 from the one to the other2 for motion has been the only variable factor4 ,if1 furthermore1 we should agree to call the translatory motion alpha1 the vibratory motion beta1 the rotary gamma1 then we should have had a conversion of alpha into beta1 of beta into gamma4 ,if we should consider the amount of transfer motion instead of the kind of motion1 we should have to say that the alpha energy had been transformed into beta and the beta into gamma4 ,illustration3 ,,fig4 #a4 ,illustration3 ,,fig4 #b4 ,what a given amount of energy will do depends only upon its form1 that is1 the kind of motion that embodies it4 ,the energy spent upon a stone thrown into the air1 giving it translatory motion1 would1 if spent upon a tuning fork1 make it sound1 but not move it from its place2 while if spent upon a top1 would enable the latter to stand upon its point as easily as a person stands on his two feet1 and to do other surprising things1 which otherwise it could not do4 ,one can1 without difficulty1 form a mechanical conception of the whole series without assuming imponderables1 or fluids or forces4 ,mechanical motion only1 by pressure1 has been transferred in certain directions at certain rates4 ,suppose now that some one should suddenly come upon a spinning top 7,fig4 #c7 while it was standing upon its point1 and1 as its motion might not be visible1 should cautiously touch it4 ,it would bound away with surprising promptness1 and1 if he were not instructed in the mechanical principles involved1 he might fairly well draw the conclusion that it was actuated by other than simple mechanical principles1 and1 for that reason1 it would be difficult to persuade him that there was nothing essentially different in the body that appeared and acted thus1 than in a stone thrown into the air2 nevertheless1 that statement would be the simple truth4 ,illustration3 ,,fig4 #c4 ,all our experience1 without a single exception1 enforces the proposition that no body moves in any direction1 or in any way1 except when some other body in contact with it presses upon it4 ,the action is direct4 ,in ,newton's letter to his friend ,bentley1 he says--,that one body should act upon another through empty space1 without the mediation of anything else by and through which their action and pressure may be conveyed from one to another1 is to me so great an absurdity that ,i believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it4 ,for mathematical purposes1 it has sometimes been convenient to treat a problem as if one body could act upon another without any physical medium between them2 but such a conception has no degree of rationality1 and ,i know of no one who believes in it as a fact4 ,if this be granted1 then our philosophy agrees with our experience1 and every body moves because it is pushed1 and the mechanical antecedent of every kind of phenomenon is to be looked for in some adjacent body possessing energy--that is1 the ability to push or produce pressure4 ,it must not be forgotten that energy is not a simple factor1 but is always a product of two factors--a mass with a velocity1 a mass with a temperature1 a quantity of electricity into a pressure1 and so on4 ,one may sometimes meet the statement that matter and energy are the two realities2 both are spoken of as entities4 ,it is much more philosophical to speak of matter and motion1 for in the absence of motion there is no energy1 and the energy varies with the amount of motion2 and furthermore1 to understand any manifestation of energy one must inquire what kind of motion is involved4 ,this we do when we speak of mechanical energy as the energy involved in a body having a translatory motion2 also1 when we speak of heat as a vibratory1 and of light as a wave motion4 ,to speak of energy without stating or implying these distinctions1 is to speak loosely and to keep far within the bounds of actual knowledge4 ,to speak thus of a body possessing energy1 or expending energy1 is to imply that the body possesses some kind of motion1 and produces pressure upon another body because it has motion4 ,tait and others have pointed out the fact1 that what is called potential energy must1 in its nature1 be kinetic4 ,tait says--,now it is impossible to conceive of a truly dormant form of energy1 whose magnitude should depend1 in any way1 upon the unit of time2 and we are forced to conclude that potential energy1 like kinetic energy1 depends 7even if unexplained or unimagined7 upon motion4 ,all this means that it is now too late to stop with energy as a final factor in any phenomenon1 that the form of motion which embodies the energy is the factor that determines what happens1 as distinguished from how much happens4 ,here1 then1 are to be found the distinctions which have heretofore been called forces2 here is embodied the proof that direct pressure of one body upon another is what causes the latter to move1 and that the direction of movement depends on the point of application1 with reference to the centre of mass4 ,it is needful now to look at the other term in the product we call energy1 namely1 the substance moving1 sometimes called matter or mass4 ,it has been mentioned that the idea of a medium filling space was present to ,newton1 but his gravitation problem did not require that he should consider other factors than masses and distances4 ,the law of gravitation as considered by him was--,every particle of matter attracts every other particle of matter with a stress which is proportional to the product of their masses1 and inversely to the squares of the distance between them4 ,here we are concerned only with the statement that every particle of matter attracts every other particle of matter4 ,everything then that possesses gravitative attraction is matter in the sense in which that term is used in this law4 ,if there be any other substance in the universe that is not thus subject to gravitation1 then it is improper to call it matter1 otherwise the law should read1 ,some particles of matter attract1 etc41 which will never do4 ,we are now assured that there is something else in the universe which has no gravitative property at all1 namely1 the ether4 ,it was first imagined in order to account for the phenomena of light1 which was observed to take about eight minutes to come from the sun to the earth4 ,then ,young applied the wave theory to the explanation of polarization and other phenomena2 and in #ahea ,foucault proved experimentally that the velocity of light was less in water than in air1 as it should be if the wave theory be true1 and this has been considered a crucial experiment which took away the last hope for the corpuscular theory1 and demonstrated the existence of the ether as a space-filling medium capable of transmitting light-waves known to have a velocity of #ahf1jjj miles per second4 ,it was called the luminiferous ether1 to distinguish it from other ethers which had also been imagined1 such as electric ether for electrical phenomena1 magnetic ether for magnetic phenomena1 and so on--as many ethers1 in fact1 as there were different kinds of phenomena to be explained4 ,it was ,faraday who put a stop to the invention of ethers1 by suggesting that the so-called luminiferous ether might be the one concerned in all the different phenomena1 and who pointed out that the arrangement of iron filings about a magnet was indicative of the direction of the stresses in the ether4 ,this suggestion did not meet the approval of the mathematical physicists of his day1 for it necessitated the abandonment of the conceptions they had worked with1 as well as the terminology which had been employed1 and made it needful to reconstruct all their work to make it intelligible--a labour which was the more distasteful as it was forced upon them by one who1 although expert enough in experimentation1 was not a mathematician1 and who boasted that the most complicated mathematical work he ever did was to turn the crank of a calculating machine2 who did all his work1 formed his conclusions1 and then said--,the work is done2 hand it over to the computers4 ,it has turned out that ,faraday's mechanical conceptions were right4 ,every one now knows of ,maxwell's work1 which was to start with ,faraday's conceptions as to magnetic phenomena1 and follow them out to their logical conclusions1 applying them to molecules and the reactions of the latter upon the ether4 ,thus he was led to conclude that light was an electro-magnetic phenomenon2 that is1 that the waves which constitute light1 and the waves produced by changing magnetism were identical in their nature1 were in the same medium1 travelled with the same velocity1 were capable of refraction1 and so on4 ,now that all this is a matter of common knowledge to-day1 it is curious to look back no further than ten years4 ,maxwell's conclusions were adopted by scarcely a physicist in the world4 ,although it was known that inductive action travelled with finite velocity in space1 and that an electro-magnet would affect the space about it practically inversely as the square of the distance1 and that such phenomena as are involved in telephonic induction between circuits could have no other meaning than the one assigned by ,maxwell1 yet nearly all the physicists failed to form the only conception of it that was possible1 and waited for ,hertz to devise apparatus for producing interference before they grasped it4 ,it was even then so new1 to some1 that it was proclaimed to be a demonstration of the existence of the ether itself1 as well as a method of producing waves short enough to enable one to notice interference phenomena4 ,it is obvious that ,hertz himself must have had the mechanics of wave-motion plainly in mind1 or he would not have planned such experiments4 ,the outcome of it all is1 that we now have experimental demonstration1 as well as theoretical reason for believing1 that the ether1 once considered as only luminiferous1 is concerned in all electric and magnetic phenomena1 and that waves set up in it by electro-magnetic actions are capable of being reflected1 refracted1 polarized1 and twisted1 in the same way as ordinary light-waves can be1 and that the laws of optics are applicable to both4 ,,chapter ,,ii ,,properties ,,of ,,matter ,,and ,,ether ,properties of ,matter and ,ether compared--,discontinuity versus ,continuity--,size of atoms--,astronomical distances--,number of atoms in the universe--,ether unlimited--,kinds of ,matter1 permanent qualities of--,atomic structure2 vortex-rings1 their properties--,ether structureless--,matter gravitative1 ,ether not--,friction in ,matter1 ,ether frictionless--,chemical properties--,energy in ,matter and in ,ether--,matter as a transformer of ,energy--,elasticity--,vibratory rates and waves--,density--,heat--,indestructibili ty of ,matter--,inertia in ,matter and in ,ether--,matter not inert--,magnetism and ,ether waves--,states of ,matter--,cohesion and chemism affected by temperature--,shearing stress in ,solids and in ,ether--,ether pressure--,sensation dependent upon ,matter--,nervous system not affected by ,ether states--,other stresses in ,ether--,transformations of ,motion--,terminology4 ,a common conception of the ether has been that it is a finer-grained substance than ordinary matter1 but otherwise so like the latter that the laws found to hold good with matter were equally applicable to the ether1 and hence the mechanical conceptions formed from experience in regard to the one have been transferred to the other1 and the properties belonging to one1 such as density1 elasticity1 etc41 have been asserted as properties of the other4 ,there is so considerable a body of knowledge bearing upon the similarities and dissimilarities of these two entities that it will be well to compare them4 ,after such comparison one will be better able to judge of the propriety of assuming them to be subject to identical laws4 #a4 ,,matter ,,is ,,discontinuous4 ,matter is made up of atoms having dimensions approximately determined to be in the neighbourhood of the one fifty-millionth of an inch in diameter4 ,these atoms may have various degrees of aggregation2--they may be in practical contact1 as in most solid bodies such as metals and rocks2 in molecular groupings as in water1 and in gases such as hydrogen1 oxygen1 and so forth1 where two1 three1 or more atoms cohere so strongly as to enable the molecules to act under ordinary circumstances like simple particles4 ,any or all of these molecules and atoms may be separated by any assignable distance from each other4 ,thus1 in common air the molecules1 though rapidly changing their positions1 are on the average about two hundred and fifty times their own diameter apart4 ,this is a distance relatively greater than the distance apart of the earth and the moon1 for two hundred and fifty times the diameter of the earth will be #hjjj #bej #b1jjj1jjj miles1 while the distance to the moon is but #bdj1jjj miles4 ,the sun is #ic1jjj1jjj miles from the earth1 and the most of the bodies of the solar system are still more widely separated1 ,neptune being nearly #cjjj millions of miles from the sun4 ,as for the fixed stars1 they are so far separated from us that1 at the present rate of motion of the solar system in its drift through space--#ejj millions of miles in a year--it would take not less than #dj1jjj years to reach the nearest star among its neighbours1 while for the more remote ones millions of years must be reckoned4 ,the huge space separating these masses is practically devoid of matter2 it is a vacuum4 ,,the ,,ether ,,is ,,continuous4 ,the idea of continuity as distinguished from discontinuity may be gained by considering what would be made visible by magnification4 ,water appears to the eye as if it were without pores1 but if sugar or salt be put into it1 either will be dissolved and quite disappear among the molecules of the water as steam does in the air1 which shows that there are some unoccupied spaces between the molecules4 ,if a microscope be employed to magnify a minute drop of water it still shows the same lack of structure as that looked at with the unaided eye4 ,if the magnifying power be the highest it may reveal a speck as small as the hundred-thousandth part of an inch1 yet the speck looks no different in character4 ,we know that water is composed of two different kinds of atoms1 hydrogen and oxygen1 for they can be separated by chemical means and kept in separate bottles1 and again made to combine to form water having all the qualities that belonged to it before it was decomposed4 ,if a very much higher magnifying power were available1 we should ultimately be able to see the individual water molecules1 and recognize their hydrogen and oxygen constituents by their difference in size1 rate of movements1 and we might possibly separate them by mechanical methods4 ,what one would see would be something very different in structure from the water as it appears to our eyes4 ,if the ether were similarly to be examined through higher and still higher magnifying powers1 even up to infinity1 there is no reason for thinking that the last examination would show anything different in structure or quality from that which was examined with low power or with no microscope at all4 ,this is all expressed by saying that the ether is a continuous substance1 without interstices1 that it fills space completely1 and1 unlike gases1 liquids1 and solids1 is incapable of absorbing or dissolving anything4 #b4 ,,matter ,,is ,,limited4 ,there appears to be a definite amount of matter in the visible universe1 a definite number of molecules and atoms4 ,how many molecules there are in a cubic inch of air under ordinary pressure has been determined1 and is represented approximately by a huge number1 something like a thousand million million millions4 ,when the diameter of a molecule has been measured1 as it has been approximately1 and found to be about one fifty-millionth of an inch1 then fifty million in a row would reach an inch1 and the cube of fifty million is #abe1jjj1jjjjjj1jjjjjj1jjjjjj1 one hundred and twenty-five thousand million million millions4 ,in a cubic foot there will of course be #agbh times that number4 ,one may if one likes find how many there may be in the earth1 and moon1 sun and planets1 for the dimensions of them are all very well known4 ,only the multiplication table need be used1 and the sum of all these will give how many molecules there are in the solar system4 ,if one should feel that the number thus obtained was not very accurate1 he might reflect that if there were ten times as many it would add but another cipher to a long line of similar ones and would not materially modify it4 ,the point is that there is a definite1 computable number4 ,if one will then add to these the number of molecules in the more distant stars and nebul1 of which there are visible about #ajj1jjj1jjj1 making such estimate of their individual size as he thinks prudent1 the sum of all will give the number of molecules in the visible universe4 ,the number is not so large but it can be written down in a minute or two4 ,those who have been to the pains to do the sum say it may be represented by seven followed by ninety-one ciphers4 ,one could easily compute how many molecules so large a space would contain if it were full and as closely packed as they are in a drop of water1 but there would be a finite and not an infinite number1 and therefore there is a limited number of atoms in the visible universe4 ,,the ,,ether ,,is ,,unlimited4 ,the evidence for this comes to us from the phenomena of light4 ,experimentally1 ether waves of all lengths are found to have a velocity of #ahf1jjj miles in a second4 ,it takes about eight minutes to reach us from the sun1 four hours from ,neptune the most distant planet1 and from the nearest fixed star about three and a half years4 ,astronomers tell us that some visible stars are so distant that their light requires not less than ten thousand years and probably more to reach us1 though travelling at the enormous rate of #ahf1jjj miles a second4 ,this means that the whole of space is filled with this medium4 ,if there were any vacant spaces1 the light would fail to get through them1 and stars beyond them would become invisible4 ,there are no such vacant spaces1 for any part of the heavens shows stars beaming continuously1 and every increase in telescopic power shows stars still further removed than any seen before4 ,the whole of this intervening space must therefore be filled with the ether4 ,some of the waves that reach us are not more than the hundred-thousandth of an inch long1 so there can be no crack or break or absence of ether from so small a section as the hundred-thousandth of an inch in all this great expanse4 ,more than this4 ,no one can think that the remotest visible stars are upon the boundary of space1 that if one could get to the most distant star he would have on one side the whole of space while the opposite side would be devoid of it4 ,space we know is of three dimensions1 and a straight line may be prolonged in any direction to an infinite distance1 and a ray of light may travel on for an infinite time and come to no end provided space be filled with ether4 ,how long the sun and stars have been shining no one knows1 but it is highly probable that the sun has existed for not less than #ajjj million years1 and has during that time been pouring its rays as radiant energy into space4 ,if then in half that time1 or #ejj millions of years1 the light had somewhere reached a boundary to the ether1 it could not have gone beyond but would have been reflected back into the ether-filled space1 and such part of the sky would be lit up by this reflected light4 ,there is no indication that anything like reflection comes to us from the sky4 ,this is equivalent to saying that the ether fills space in every direction away from us to an unlimited distance1 and so far is itself unlimited4 #c4 ,,matter ,,is ,,heterogeneous4 ,the various kinds of matter we are acquainted with are commonly called the elements4 ,these when combined in various ways exhibit characteristic phenomena which depend upon the kinds of matter1 the structure and motions which are involved4 ,there are some seventy different kinds of this elemental matter which may be identified as constituents of the earth4 ,many of the same elements have been identified in the sun and stars1 such for instance as hydrogen1 carbon1 and iron4 ,such phenomena lead us to conclude that the kinds of matter elsewhere in the universe are identical with such as we are familiar with1 and that elsewhere the variety is as great4 ,the qualities of the elements1 within a certain range of temperature1 are permanent2 they are not subject to fluctuations1 though the qualities of combinations of them may vary indefinitely4 ,the elements therefore may be regarded as retaining their identity in all ordinary experience4 ,,the ,,ether ,,is ,,homogeneous4 ,one part of the ether is precisely like any other part everywhere and always1 and there are no such distinctions in it as correspond with the elemental forms of matter4 #d4 ,,matter ,,is ,,atomic4 ,there is an ultimate particle of each one of the elements which is practically absolute and known as an atom4 ,the atom retains its identity through all combinations and processes4 ,it may be here or there1 move fast or slow1 but its atomic form persists4 ,,the ,,ether ,,is ,,non-,,atomic4 ,one might infer1 from what has already been said about continuity1 that the ether could not be constituted of separable particles like masses of matter2 for no matter how minute they might be1 there would be interspaces and unoccupied spaces which would present us with phenomena which have never been seen4 ,it is the general consensus of opinion among those who have studied the subject that the ether is not atomic in structure4 #e4 ,,matter ,,has ,,definite ,,structure4 ,every atom of every element is so like every other atom of the same element as to exhibit the same characteristics1 size1 weight1 chemical activity1 vibratory rate1 etc41 and it is thus shown conclusively that the structural form of the elemental particles is the same for each element1 for such characteristic reactions as they exhibit could hardly be if they were mechanically unlike4 ,of what form the atoms of an element may be is not very definitely known4 ,the earlier philosophers assumed them to be hard round particles1 but later thinkers have concluded that atoms of such a character are highly improbable1 for they could not exhibit in this case the properties which the elements do exhibit4 ,they have therefore dismissed such a conception from consideration4 ,in place of this hypothesis has been substituted a very different idea1 namely1 that an atom is a vortex-ring#a of ether floating in the ether1 as a smoke-ring puffed out by a locomotive in still air may float in the air and show various phenomena4 ,footnote #a3 ,vortex-rings for illustration may be made by having a wooden box about a foot on a side1 with a round orifice in the middle of one side1 and the side opposite covered with stout cloth stretched tight over a framework4 ,a saucer containing strong ammonia water1 and another containing strong hydrochloric acid1 will cause dense fumes in the box1 and a tap with the hand upon the cloth back will force out a ring from the orifice4 ,these may be made to follow and strike each other1 rebounding and vibrating1 apparently attracting each other and being attracted by neighbouring bodies4 ,by filling the mouth with smoke1 and pursing the lips as if to make the sound o1 one may make fifteen or twenty small rings by snapping the cheek with the finger4 ,a vortex-ring produced in the air behaves in the most surprising manner4 ,illustration3 ,,fig4 #d4--,method of making vortex-rings and their behaviour4 #a4 ,it retains its ring form and the same material rotating as it starts with4 #b4 ,it can travel through the air easily twenty or thirty feet in a second without disruption4 #c4 ,its line of motion when free is always at right angles to the plane of the ring4 #d4 ,it will not stand still unless compelled by some object4 ,if stopped in the air it will start up itself to travel on without external help4 #e4 ,it possesses momentum and energy like a solid body4 #f4 ,it is capable of vibrating like an elastic body1 making a definite number of such vibrations per second1 the degree of elasticity depending upon the rate of vibration4 ,the swifter the rotation1 the more rigid and elastic it is4 #g4 ,it is capable of spinning on its own axis1 and thus having rotary energy as well as translatory and vibratory4 #h4 ,it repels light bodies in front of it1 and attracts into itself light bodies in its rear4 #i4 ,if projected along parallel with the top of a long table1 it will fall upon it every time1 just as a stone thrown horizontally will fall to the ground4 #aj4 ,if two rings of the same size be travelling in the same line1 and the rear one overtakes the other1 the front one will enlarge its diameter1 while the rear one will contract its own till it can go through the forward one1 when each will recover its original diameter1 and continue on in the same direction1 but vibrating1 expanding and contracting their diameters with regularity4 #aa4 ,if two rings be moving in the same line1 but in opposite directions1 they will repel each other when near1 and thus retard their speed4 ,if one goes through the other1 as in the former case1 it may quite lose its velocity1 and come to a standstill in the air till the other has moved on to a distance1 when it will start up in its former direction4 #ab4 ,if two rings be formed side by side1 they will instantly collide at their edges1 showing strong attraction4 #ac4 ,if the collision does not destroy them1 they may either break apart at the point of the collision1 and then weld together into a single ring with twice the diameter1 and then move on as if a single ring had been formed1 or they may simply bounce away from each other1 in which case they always rebound in a plane at right angles to the plane of collision4 ,that is1 if they collided on their sides1 they would rebound so that one went up and the other down4 #ad4 ,three may in like manner collide and fuse into a single ring4 ,such rings formed in air by a locomotive may rise wriggling in the air to the height of several hundred feet1 but they are soon dissolved and disappear4 ,this is because the friction and viscosity of the air robs the rings of their substance and energy4 ,if the air were without friction this could not happen1 and the rings would then be persistent1 and would retain all their qualities4 ,suppose then that such rings were produced in a medium without friction as the ether is believed to be1 they would be permanent structures with a variety of properties4 ,they would occupy space1 have definite form and dimensions1 momentum1 energy1 attraction and repulsion1 elasticity2 obey the laws of motion1 and so far behave quite like such matter as we know4 ,for such reasons it is thought by some persons to be not improbable that the atoms of matter are minute vortex-rings of ether in the ether4 ,that which distinguishes the atom from the ether is the form of motion which is embodied in it1 and if the motion were simply arrested1 there would be nothing to distinguish the atom from the ether into which it dissolved4 ,in other words1 such a conception makes the atoms of matter a form of motion of the ether1 and not a created something put into the ether4 ,,the ,,ether ,,is ,,structureless4 ,if the ether be the boundless substance described1 it is clear it can have no form as a whole1 and if it be continuous it can have no minute structure4 ,if not constituted of atoms or molecules there is nothing descriptive that can be said about it4 ,a molecule or a particular mass of matter could be identified by its form1 and is thus in marked contrast with any portion of ether1 for the latter could not be identified in a similar way4 ,one may therefore say that the ether is formless4 #f4 ,,matter ,,is ,,gravitative4 ,the law of gravitation is held as being universal4 ,according to it every particle of matter in the universe attracts every other particle4 ,the evidence for this law in the solar system is complete4 ,sun1 planets1 satellites1 comets and meteors are all controlled by gravitation1 and the movements of double stars testify to its activity among the more distant bodies of the universe4 ,the attraction does not depend upon the kind of matter nor the arrangement of molecules or atoms1 but upon the amount or mass of matter present1 and if it be of a definite kind of matter1 as of hydrogen or iron1 the gravitative action is proportional to the number of atoms4 ,,the ,,ether ,,is ,,gravitationless4 ,one might infer already that if the ether were structureless1 physical laws operative upon such material substances as atoms could not be applicable to it1 and so indeed all the evidence we have shows that gravitation is not one of its properties4 ,if it were1 and it behaved in any degree like atomic structures1 it would be found to be denser in the neighbourhood of large bodies like the earth1 planets1 and the sun4 ,light would be turned from its straight path while travelling in such denser medium1 or made to move with less velocity4 ,there is not the slightest indication of any such effect anywhere within the range of astronomical vision4 ,gravitation then is a property belonging to matter and not to ether4 ,the impropriety of thinking or speaking of the ether as matter of any kind will be apparent if one reflects upon the significance of the law of gravitation as stated4 ,every particle of matter in the universe attracts every other particle4 ,if there be anything else in the universe which has no such quality1 then it should not be called matter1 else the law should read3 ,some particles of matter attract some other particles1 which would be no law at all1 for a real physical law has no exceptions any more than the multiplication table has4 ,physical laws are physical relations1 and all such relations are quantitative4 #g4 ,,matter ,,is ,,frictionable4 ,a bullet shot into the air has its velocity continuously reduced by the air1 to which its energy is imparted by making it move out of its way4 ,a railway train is brought to rest by the friction brake upon the wheels4 ,the translatory energy of the train is transformed into the molecular energy called heat4 ,the steamship requires to propel it fast1 a large amount of coal for its engines1 because the water in which it moves offers great friction--resistance which must be overcome4 ,whenever one surface of matter is moved in contact with another surface there is a resistance called friction1 the moving body loses its rate of motion1 and will presently be brought to rest unless energy be continuously supplied4 ,this is true for masses of matter of all sizes and with all kinds of motion4 ,friction is the condition for the transformation of all kinds of mechanical motions into heat4 ,the test of the amount of friction is the rate of loss of motion4 ,a top will spin some time in the air because its point is small4 ,it will spin longer on a plate than on the carpet1 and longer in a vacuum than in the air1 for it does not have the air friction to resist it1 and there is no kind or form of matter not subject to frictional resistance4 ,,the ,,ether ,,is ,,frictionless4 ,the earth is a mass of matter moving in the ether4 ,in the equatorial region the velocity of a point is more than a thousand miles in an hour1 for the circumference of the earth is #be1jjj miles1 and it turns once on its axis in #bd hours1 which is the length of the day4 ,if the earth were thus spinning in the atmosphere1 the latter not being in motion1 the wind would blow with ten times hurricane velocity4 ,the friction would be so great that nothing but the foundation rocks of the earth's crust could withstand it1 and the velocity of rotation would be reduced appreciably in a relatively short time4 ,the air moves along with the earth as a part of it1 and consequently no such frictional destruction takes place1 but the earth rotates in the ether with that same rate1 and if the ether offered resistance it would react so as to retard the rotation and increase the length of the day4 ,astronomical observations show that the length of the day has certainly not changed so much as the tenth of a second during the past #bjjj years4 ,the earth also revolves about the sun1 having a speed of about #ai miles in a second1 or #fh1jjj miles an hour4 ,this motion of the earth and the other planets about the sun is one of the most stable phenomena we know4 ,the mean distance and period of revolution of every planet is unalterable in the long run4 ,if the earth had been retarded by its friction in the ether the length of the year would have been changed1 and astronomers would have discovered it4 ,they assert that a change in the length of a year by so much as the hundredth part of a second has not happened during the past thousand years4 ,this then is testimony1 that a velocity of nineteen miles a second for a thousand years has produced no effect upon the earth's motion that is noticeable4 ,nineteen miles a second is not a very swift astronomical motion1 for comets have been known to have a velocity of #djj miles a second when in the neighbourhood of the sun1 and yet they have not seemed to suffer any retardation1 for their orbits have not been shortened4 ,some years ago a comet was noticed to have its periodic time shortened an hour or two1 and the explanation offered at first was that the shortening was due to friction in the ether although no other comet was thus affected4 ,the idea was soon abandoned1 and to-day there is no astronomical evidence that bodies having translatory motion in the ether meet with any frictional resistance whatever4 ,if a stone could be thrown in interstellar space with a velocity of fifty feet a second it would continue to move in a straight line with the same speed for any assignable time4 ,as has been said1 light moves with the velocity of #ahf1jjj miles per second1 and it may pursue its course for tens of thousands of years4 ,there is no evidence that it ever loses either its wave-length or energy4 ,it is not transformed as friction would transform it1 else there would be some distance at which light of given wave-length and amplitude would be quite extinguished4 ,the light from distant stars would be different in character from that coming from nearer stars4 ,furthermore1 as the whole solar system is drifting in space some #ejj1jjj1jjj of miles in a year1 new stars would be coming into view in that direction1 and faint stars would be dropping out of sight in the opposite direction--a phenomenon which has not been observed4 ,altogether the testimony seems conclusive that the ether is a frictionless medium1 and does not transform mechanical motion into heat4 #h4 ,,matter ,,is ,,olotropic4 ,that is1 its properties are not alike in all directions4 ,chemical phenomena1 crystallization1 magnetic and electrical phenomena show each in their way that the properties of atoms are not alike on opposite faces4 ,atoms combine to form molecules1 and molecules arrange themselves in certain definite geometric forms such as cubes1 tetrahedra1 hexagonal prisms and stellate forms1 with properties emphasized on certain faces or ends4 ,thus quartz will twist a ray of light in one direction or the other1 depending upon the arrangement which may be known by the external form of the crystal4 ,calc spar will break up a ray of light into two parts if the light be sent through it in certain directions1 but not if in another4 ,tourmaline polarizes light sent through its sides and becomes positively electrified at one end while being heated4 ,some substances will conduct sound or light or heat or electricity better in one direction than in another4 ,all matter is magnetic in some degree1 and that implies polarity4 ,if one will recall the structure of a vortex-ring1 he will see how all the motion is inward on one side and outward on the other1 which gives different properties to the two sides3 a push away from it on one side and a pull toward it on the other4 ,,the ,,ether ,,is ,,isotropic4 ,that is1 its properties are alike in every direction4 ,there is no distinction due to position4 ,a mass of matter will move as freely in one direction as in another2 a ray of light of any wave-length will travel in it in one direction as freely as in any other2 neither velocity nor direction are changed by the action of the ether alone4 #i4 ,,matter ,,is ,,chemically ,,selective4 ,when the elements combine to form molecules they always combine in definite ways and in definite proportions4 ,carbon will combine with hydrogen1 but will drop it if it can get oxygen4 ,oxygen will combine with iron or lead or sodium1 but cannot be made to combine with fluorine4 ,no more than two atoms of oxygen can be made to unite with one carbon atom1 nor more than one hydrogen with one chlorine atom4 ,there is thus an apparent choice for the kind and number of associates in molecular structure1 and the instability of a molecule depends altogether upon the presence in its neighbourhood of other atoms for which some of the elements in the molecule have a stronger attraction or affinity than they have for the atoms they are now combined with4 ,thus iron is not stable in the presence of water molecules1 and it becomes iron oxide2 iron oxide is not stable in the presence of hot sulphur1 it becomes an iron sulphide4 ,all the elements are thus selective1 and it is by such means that they may be chemically identified4 ,there is no phenomenon in the ether that is comparable with this4 ,evidently there could not be unless there were atomic structures having in some degree different characteristics which we know the ether to be without4 #aj4 ,,the ,,elements ,,of ,,matter ,,are ,,harmonically ,,related4 ,it is possible to arrange the elements in the order of their atomic weights in columns which will show communities of property4 ,newlands1 ,mendeleff1 ,meyer1 and others have done this4 ,the explanation for such an arrangement has not yet been forthcoming1 but that it expresses a real fact is certain1 for in the original scheme there were several gaps representing undiscovered elements1 the properties of which were predicted from that of their associates in the table4 ,some of these have since been discovered1 and their atomic weight and physical properties accord with those predicted4 ,with the ether such a scheme is quite impossible1 for the very evident reason that there are no different things to have relation with each other4 ,every part is just like every other part4 ,where there are no differences and no distinctions there can be no relations4 ,the ether is quite harmonic without relations4 #aa4 ,,matter ,,embodies ,,energy4 ,so long as the atoms of matter were regarded as hard round particles1 they were assumed to be inert and only active when acted upon by what were called forces1 which were held to be entities of some sort1 independent of matter4 ,these could pull or push it here or there1 but the matter was itself incapable of independent activity4 ,all this is now changed1 and we are called upon to consider every atom as being itself a form of energy in the same sense as heat or light are forms of energy1 the energy being embodied in particular forms of motion4 ,light1 for instance1 is a wave motion of the ether4 ,an atom is a rotary ring of ether4 ,stop the wave motion1 and the light would be annihilated4 ,stop the rotation1 and the atom would be annihilated for the same reason4 ,as the ray of light is a particular embodiment of energy1 and has no existence apart from it1 so an atom is to be regarded as an embodiment of energy4 ,on a previous page it is said that energy is the ability of one body to act upon and move another in some degree4 ,an atom of any kind is not the inert thing it has been supposed to be1 for it can do something4 ,even at absolute zero1 when all its vibratory or heat energy would be absent1 it would be still an elastic whirling body pulling upon every other atom in the universe with gravitational energy1 twisting other atoms into conformity with its own position with its magnetic energy2 and1 if such ether rings are like the rings which are made in air1 will not stand still in one place even if no others act upon it1 but will start at once by its own inherent energy to move in a right line at right angles to its own plane and in the direction of the whirl inside the ring4 ,two rings of wood or iron might remain in contact with each other for an indefinite time1 but vortex-rings will not1 but will beat each other away as two spinning tops will do if they touch ever so gently4 ,if they do not thus separate it is because there are other forms of energy acting to press them together1 but such external pressure will be lessened by the rings' own reactions4 ,it is true that in a frictionless medium like the ether one cannot at present see how such vortex-rings could be produced in it4 ,certainly not by any such mechanical methods as are employed to make smoke-rings in air1 for the friction of the air is the condition for producing them4 ,however they came to be1 there is implied the previous existence of the ether and of energy in some form capable of acting upon it in a manner radically different from any known in physical science4 ,there is good spectroscopic evidence that in some way elements of different kinds are now being formed in nebul1 for the simplest show the presence of hydrogen alone4 ,as they increase in complexity other elements are added1 until the spectrum exhibits all the elements we know of4 ,it has thus seemed likely either that most of what are called elements are composed of molecular groupings of some fundamental element1 which by proper physical methods might be decomposed1 as one can now decompose a molecule of ammonia or sulphuric acid1 or that the elements are now being created by some extra-physical process in those far-off regions4 ,in either case an atom is the embodiment of energy in such a form as to be permanent under ordinary physical circumstances1 but of which1 if in any manner it should be destroyed1 only the form would be lost4 ,the ether would remain1 and the energy which was embodied would be distributed in other ways4 ,,the ,,ether ,,is ,,endowed ,,with ,,energy4 ,the distinction between energy in matter and energy in the ether will be apparent1 on considering that both the ether and energy in some form must be conceived as existing independent of matter2 though every atom were annihilated1 the ether would remain and all the energy embodied in the atoms would be still in existence in the ether4 ,the atomic energy would simply be dissolved4 ,one can easily conceive the ether as the same space-filling1 continuous1 unlimited medium1 without an atom in it4 ,on this assumption it is clear that no form of energy with which we have to deal in physical science would have any existence in the ether2 for every one of those forms1 gravitational1 thermal1 electric1 magnetic1 or any other--all are the results of the forms of energy in matter4 ,if there were no atoms1 there would be no gravitation1 for that is the attraction of atoms upon each other4 ,if there were no atoms1 there could be no atomic vibration1 therefore no heat1 and so on for each and all4 ,nevertheless1 if an atom be the embodiment of energy1 there must have been energy in the ether before any atom existed4 ,one of the properties of the ether is its ability to distribute energy in certain ways1 but there is no evidence that of itself it ever transforms energy4 ,once a given kind of energy is in it1 it does not change2 hence for the apparition of a form of energy1 like the first vortex-ring1 there must have been not only energy1 but some other agency capable of transforming that energy into a permanent structure4 ,to the best of our knowledge to-day1 the ether would be absolutely helpless4 ,such energy as was active in forming atoms must be called by another name than what is appropriate for such transformations as occur when1 for instance1 the mechanical energy of a bullet is transformed into heat when the target is struck4 ,behind the ether must be assumed some agency1 directing and controlling energy in a manner totally different from any agency1 which is operative in what we call physical science4 ,nothing short of what is called a miracle will do--an event without a physical antecedent in any way necessarily related to its factors1 as is the fact of a stone related to gravity or heat to an electric current4 ,ether energy is an endowment instead of being an embodiment1 and implies antecedents of a super-physical kind4 #ab4 ,,matter ,,is ,,an ,,energy ,,transformer4 ,as each different kind of energy represents some specific form of motion1 and vice vers1 some sort of mechanism is needful for transforming one kind into another1 therefore molecular structure of one kind or another is essential4 ,the transformation is a mechanical process1 and matter in some particular and appropriate form is the condition of its taking place4 ,if heat appears1 then its antecedent has been some other form of motion acting upon the substance heated4 ,it may have been the mechanical motion of another mass of matter1 as when a bullet strikes a target and becomes heated2 or it may be friction1 as when a car-axle heats when run without proper oiling to reduce friction2 or it may be condensation1 as when tinder is ignited by condensing the air about it2 or chemical reactions1 when molecular structure is changed as in combustion1 or an electrical current1 which implies a dynamo and steam-engine or water-power4 ,if light appears1 its antecedent has been impact or friction1 condensation or chemical action1 and if electricity appears the same sort of antecedents are present4 ,whether the one or the other of these forms of energy is developed1 depends upon what kind of a structure the antecedent energy has acted upon4 ,if radiant energy1 so-called1 falls upon a mass of matter1 what is absorbed is at once transformed into heat or into electric or magnetic effects2 which one of these depends upon the character of the mechanism upon which the radiant energy acts1 but the radiant energy itself1 which consists of ether-waves1 is traceable back in every case to a mass of matter having definite characteristic motions4 ,one may therefore say with certainty that every physical phenomenon is a change in the direction1 or velocity1 or character1 of the energy present1 and such change has been produced by matter acting as a transformer4 ,,the ,,ether ,,is ,a ,,non-,,transformer4 ,it has already been said that the absence of friction in the ether enables light-waves to maintain their identity for an indefinite time1 and to an indefinitely great distance4 ,in a uniform1 homogeneous substance of any kind1 any kind of energy which might be in it would continue in it without any change4 ,uniformity and homogeneity imply similarity throughout1 and the necessary condition for transformation is unlikeness4 ,one might not look for any kind of physical phenomenon which was not due to the presence and activity of some heterogeneity4 ,as a ray of light continues a ray of light so long as it exists in free ether1 so all kinds of radiations1 of whatever wave-length1 continue identical until they fall upon some mechanical structure called matter4 ,translatory motion continues translatory1 rotary continues rotary1 and vibratory continues to be vibratory1 and no transforming change can take place in the absence of matter4 ,the ether is helpless4 #ac4 ,,matter ,,is ,,elastic4 ,it is commonly stated that certain substances1 like putty and dough1 are inelastic1 while some other substances1 like glass1 steel1 and wood1 are elastic4 ,this quality of elasticity1 as manifested in such different degrees1 depends upon molecular combinations2 some of which1 as in glass and steel1 are favourable for exhibiting it1 while others mask it1 for the ultimate atoms of all kinds are certainly highly elastic4 ,the measure of elasticity in a mass of matter is the velocity with which a wave-motion will be transmitted through it4 ,thus the elasticity of the air determines the velocity of sound in it4 ,if the air be heated1 the elasticity is increased and the sound moves faster4 ,the rates of such sound-conduction range from a few feet in a second to about #af1jjj1 five times swifter than a cannon ball4 ,in such elastic bodies as vibrate to and fro like the prongs of a tuning-fork1 or give sounds of a definite pitch1 the rate of vibration is determined by the size and shape of the body as well as by their elementary composition4 ,the smaller a body is1 the higher its vibratory rate1 if it be made of the same material and the form remains the same4 ,thus a tuning-fork1 that may be carried in the waistcoat-pocket1 may vibrate #ejj times a second4 ,if it were only the fifty-millionth of an inch in size1 but of the same material and form1 it would vibrate #cj1jjj1jjjjjj times a second2 and if it were made of ether1 instead of steel1 it would vibrate as many times faster as the velocity of waves in the ether is greater than it is in steel1 and would be as many as #djj1jjjjjj1jjjjjj times per second4 ,the amount of displacement1 or the amplitude of vibration1 with the pocket-fork might be no more than the hundredth of an inch1 and this rate measured as translation velocity would be but five inches per second4 ,if the fork were of atomic magnitude1 and should swing its sides one half the diameter of the atom1 or say the hundred-millionth of an inch1 the translational velocity would be equivalent to about eighty miles a second1 or a hundred and fifty times the velocity of a cannon ball1 which may be reckoned at about #cjjj feet4 ,that atoms really vibrate at the above rate per second is very certain1 for their vibrations produce ether-waves the length of which may be accurately measured4 ,when a tuning-fork vibrates #ejj times a second1 and the sound travels #aajj feet in the same interval1 the length of each wave will be found by dividing the velocity in the air by the number of vibrations1 or #aajj #ejj #b4b feet4 ,in like manner1 when one knows the velocity and wave-length1 he may compute the number of vibrations by dividing the velocity by the wave-length4 ,now the velocity of the waves called light is #ahf1jjj miles a second1 and a light-wave may be one forty thousandth of an inch long4 ,the atom that produces the wave must be vibrating as many times per second as the fifth thousandth of an inch is contained in #ahf1jjj miles4 ,reducing this number to inches we have #ahf1jjj #ebhj #ab ------------------- #djj1jjj1jjj1jjj1jjj1 nearly4 #a_/dj1jjj ,this shows that the atoms are minute elastic bodies that change their form rapidly when struck4 ,as rapid as the change is1 yet the rate of movement is only one-fifth that of a comet when near the sun1 and is therefore easily comparable with other velocities observed in masses of matter4 ,these vibratory motions1 due to the elasticity of the atoms1 is what constitutes heat4 ,,the ,,ether ,,is ,,elastic4 ,the elasticity of a mass of matter is its ability to recover its original form after that form has been distorted4 ,there is implied that a stress changes its shape and dimensions1 which in turn implies a limited mass and relative change of position of parts and some degree of discontinuity4 ,from what has been said of the ether as being unlimited1 continuous1 and not made of atoms or molecules1 it will be seen how difficult1 if not impossible1 it is to conceive how such a property as elasticity1 as manifested in matter1 can be attributed to the ether1 which is incapable of deformation1 either in structure or form1 the latter being infinitely extended in every direction and therefore formless4 ,nevertheless1 certain forms of motion1 such as light-waves1 move in it with definite velocity1 quite independent of how they originate4 ,this velocity of #ahf1jjj miles a second so much exceeds any movement of a mass of matter that the motions can hardly be compared4 ,thus if #djj miles per second be the swiftest speed of any mass of matter known--that of a comet near the sun--the ether-wave moves #ahf1jjj #djj #dfe times faster than such comet1 and #ijj1jjj times faster than sound travels in air4 ,it is clear that if this rate of motion depends upon elasticity1 the elasticity must be of an entirely different type from that belonging to matter1 and cannot be defined in any such terms as are employed for matter4 ,if one considers gravitative phenomena1 the difficulty is enormously increased4 ,the orbit of a planet is never an exact ellipse1 on account of the perturbations produced by the planetary attractions--perturbations which depend upon the direction and distance of the attracting bodies4 ,these1 however1 are so well known that slight deviations are easily noticed4 ,if gravitative attraction took any such appreciable time to go from one astronomical body to another as does light1 it would make very considerable differences in the paths of the planets and the earth4 ,indeed1 if the velocity of gravitation were less than a million times greater than that of light1 its effects would have been discovered long ago4 ,it is therefore considered that the velocity of gravitation cannot be less than #ahfjjj1jjjjjj miles per second4 ,how much greater it may be no one can guess4 ,seeing that gravitation is ether-pressure1 it does not seem probable that its velocity can be infinite4 ,however that may be1 the ability of the ether to transmit pressure and various disturbances1 evidently depends upon properties so different from those that enable matter to transmit disturbances that they deserve to be called by different names4 ,to speak of the elasticity of the ether may serve to express the fact that energy may be transmitted at a finite rate in it1 but it can only mislead one's thinking if he imagines the process to be similar to energy transmission in a mass of matter4 ,the two processes are incomparable4 ,no other word has been suggested1 and perhaps it is not needful for most scientific purposes that another should be adopted1 but the inappropriateness of the one word for the different phenomena has long been felt4 #ad4 ,,matter ,,has ,,density4 ,this quality is exhibited in two ways in matter4 ,in the first1 the different elements in their atomic form have different masses or atomic weights4 ,an atom of oxygen weighs sixteen times as much as an atom of hydrogen2 that is1 it has sixteen times as much matter1 as determined by weight1 as the hydrogen atom has1 or it takes sixteen times as many hydrogen atoms to make a pound as it takes of oxygen atoms4 ,this is generally expressed by saying that oxygen has sixteen times the density of hydrogen4 ,in like manner1 iron has fifty-six times the density1 and gold one hundred and ninety-six4 ,the difference is one in the structure of the atomic elements4 ,if one imagines them to be vortex-rings1 they may differ in size1 thickness1 and rate of rotation2 either of these might make all the observed difference between the elements1 including their density4 ,in the second way1 density implies compactness of molecules4 ,thus if a cubic foot of air be compressed until it occupies but half a cubic foot1 each cubic inch will have twice as many molecules in it as at first4 ,the amount of air per unit volume will have been doubled1 the weight will have been doubled1 the amount of matter as determined by its weight will have been doubled1 and consequently we say its density has been doubled4 ,if a bullet or a piece of iron be hammered1 the molecules are compacted closer together1 and a greater number can be got into a cubic inch when so condensed4 ,in this sense1 then1 density means the number of molecules in a unit of space1 a cubic inch or cubic centimeter4 ,there is implied in this latter case that the molecules do not occupy all the available space1 that they may have varying degrees of closeness2 in other words1 matter is discontinuous1 and therefore there may be degrees in density4 ,,the ,,ether ,,has ,,density4 ,it is common to have the degree of density of the ether spoken of in the same way1 and for the same reason1 that its elasticity is spoken of4 ,the rate of transmission of a physical disturbance1 as of a pressure or a wave-motion in matter1 is conditioned by its degree of density2 that is1 the amount of matter per cubic inch as determined by its weight2 the greater the density the slower the rate4 ,so if rate of speed and elasticity be known1 the density may be computed4 ,in this way the density of the ether has been deduced by noting the velocity of light4 ,the enormous velocity is supposed to prove that its density is very small1 even when compared with hydrogen4 ,this is stated to be about equal to that of the air at the height of two hundred and ten miles above the surface of the earth1 where the air molecules are so few that a molecule might travel for #fj1jjj1jjj miles without coming in collision with another molecule4 ,in air of ordinary density1 a molecule can on the average move no further than about the two-hundred-and-fifty-thousandth of an inch without such collision4 ,it is plain the density of the ether is so far removed from the density of anything we can measure1 that it is hardly comparable with such things4 ,if1 in addition1 one recalls the fact that the ether is homogeneous1 that is all of one kind1 and also that it is not composed of atoms and molecules1 then degree of compactness and number of particles per cubic inch have no meaning1 and the term density1 if used1 can have no such meaning as it has when applied to matter4 ,there is no physical conception gained from the study of matter that can be useful in thinking of it4 ,as with elasticity1 so density is inappropriately applied to the ether1 but there is no substitute yet offered4 #ae4 ,,matter ,,is ,,heatable4 ,so long as heat was thought to be some kind of an imponderable thing1 which might retain its identity whether it were in or out of matter1 its real nature was obscured by the name given to it4 ,an imponderable was a mysterious something like a spirit1 which was the cause of certain phenomena in matter4 ,heat1 light1 electricity1 magnetism1 gravitation1 were due to such various agencies1 and no one concerned himself with the nature of one or the other4 ,bacon thought that heat was a brisk agitation of the particles of substances1 and ,count ,rumford and ,sir ,humphrey ,davy thought they proved that it could be nothing else1 but they convinced nobody4 ,mayer in ,germany and ,joule in ,england showed that quantitative relations existed between work done and heat developed1 but not until the publication of the book called ,heat as a ,mode of ,motion1 was there a change of opinion and terminology as to the nature of heat4 ,for twenty years after that it was common to hear the expressions heat1 and radiant heat1 to distinguish between phenomena in matter and what is now called radiant energy radiations1 or simply ether-waves4 ,not until the necessity arose for distinguishing between different forms of energy1 and the conditions for developing them1 did it become clear to all that a change in the form of energy implied a change in the form of motion that embodied it4 ,the energy called heat energy was proved to be a vibratory motion of molecules1 and what happened in the ether as a result of such vibrations is no longer spoken of as heat1 but as ether waves4 ,when it is remembered that the ultimate atoms are elastic bodies1 and that they will1 if free1 vibrate in a periodic manner when struck or shaken in any way1 just as a ball will vibrate after it is struck1 it is easy to keep in mind the distinction between the mechanical form of motion spent in striking and the vibratory form of the motion produced by it4 ,the latter is called heat2 no other form of motion than that is properly called heat4 ,it is this alone that represents temperature1 the rate and amplitude of such atomic and molecular vibrations as constitute change1 of form4 ,where molecules like those in a gas have some freedom of movement between impacts1 they bound away from each other with varying velocities4 ,the path of such motion may be long or short1 depending upon the density or compactness of the molecules1 but such changes in position are not heat for a molecule any more than the flight of a musket ball is heat1 though it may be transformed into heat on striking the target4 ,this conception of heat as the rapid change in the form of atoms and molecules1 due to their elasticity1 is a phenomenon peculiar to matter4 ,it implies a body possessing form that may be changed2 elasticity1 that its changes may be periodic1 and degrees of freedom that secure space for the changes4 ,such a body may be heated4 ,its temperature will depend upon the amplitude of such vibrations1 and will be limited by the maximum amplitude4 ,,the ,,ether ,,is ,,unheatable4 ,the translatory motion of a mass of matter1 big or little1 through the ether1 is not arrested in any degree so far as observed1 but the internal vibratory motion sets up waves in the ether1 the ether absorbs the energy1 and the amplitude is continually lessened4 ,the motion has been transferred and transformed2 transferred from matter to the ether1 and transformed from vibratory to waves travelling at the rate of #ahf1jjj miles per second4 ,the latter is not heat1 but the result of heat4 ,with the ether constituted as described1 such vibratory motion as constitutes heat is impossible to it1 and hence the characteristic of heat-motion in it is impossible2 it cannot therefore be heated4 ,the space between the earth and the sun may have any assignable amount of energy in the form of ether waves or light1 but not any temperature4 ,one might loosely say that the temperature of empty spaces was absolute zero1 but that would not be quite correct1 for the idea of temperature cannot properly be entertained as applicable to the ether4 ,to say that its temperature was absolute zero1 would serve to imply that it might be higher1 which is inadmissible4 ,when energy has been transformed1 the old name by which the energy was called must be dropped4 ,ether cannot be heated4 #af4 ,,matter ,,is ,,indestructible4 ,this is commonly said to be one of the essential properties of matter4 ,all that is meant by it1 however1 is simply this3 ,in no physical or chemical process to which it has been experimentally subjected has there been any apparent loss4 ,the matter experimented upon may change from a solid or liquid to a gas1 or the molecular change called chemical may result in new compounds1 but the weight of the material and its atomic constituents have not appreciably changed4 ,that matter cannot be annihilated is only the converse of the proposition that matter cannot be created1 which ought always to be modified by adding1 by physical or chemical processes at present known4 ,a chemist may work with a few grains of a substance in a beaker1 or test-tube1 or crucible1 and after several solutions1 precipitations1 fusions and dryings1 may find by final weighing that he has not lost any appreciable amount1 but how much is an appreciable amount8 ,a fragment of matter the ten-thousandth of an inch in diameter has too small a weight to be noted in any balance1 yet it would be made up of thousands of millions of atoms4 ,hence if1 in the processes to which the substance had been subjected1 there had been the total annihilation of thousands of millions of atoms1 such phenomenon would not have been discovered by weighing4 ,neither would it have been discovered if there had been a similar creation or development of new matter4 ,all that can be asserted concerning such events is1 that they have not been discovered with our means of observation4 ,the alchemists sought to transform one element into another1 as lead into gold4 ,they did not succeed4 ,it was at length thought to be impossible1 and the attempt to do it an absurdity4 ,lately1 however1 telescopic observation of what is going on in nebul1 which has already been referred to1 has somewhat modified ideas of what is possible and impossible in that direction4 ,it is certainly possible roughly to conceive how such a structure as a vortex-ring in the ether might be formed4 ,with certain polarizing apparatus it is possible to produce rays of circularly polarized light4 ,these are rays in which the motion is an advancing rotation like the wire in a spiral spring4 ,if such a line of rotations in the ether were flexible1 and the two ends should come together1 there is reason for thinking they would weld together1 in which case the structure would become a vortex-ring and be as durable as any other4 ,there is reason for believing1 also1 that somewhat similar movements are always present in a magnetic field1 and though we do not know how to make them close up in the proper way1 it does not follow that it is impossible for them to do so4 ,the bearing of all this upon the problem of the transmutation of elements is evident4 ,no one now will venture to deny its possibility as strongly as it was denied a generation ago4 ,it will also lead one to be less confident in the theory that matter is indestructible4 ,assuming the vortex-ring theory of atoms to be true1 if in any way such a ring could be cut or broken1 there would not remain two or more fragments of a ring or atom4 ,the whole would at once be dissolved into the ether4 ,the ring and rotary energy that made it an atom would be destroyed1 but not the substance it was made of1 nor the energy which was embodied therein4 ,for a long time philosophers have argued1 and commonsense has agreed with them1 that an atom which could not be ideally broken into two parts was impossible1 that one could at any rate think of half an atom as a real objective possibility4 ,this vortex-ring theory shows easily how possible it is to-day to think what once was philosophically incredible4 ,it shows that metaphysical reasoning may be ever so clear and apparently irrefragable1 yet for all that it may be very unsound4 ,the trouble does not come so much from the logic as from the assumption upon which the logic is founded4 ,in this particular case the assumption was that the ultimate particles of matter were hard1 irrefragable somethings1 without necessary relations to anything else1 or to energy1 and irrefragable only because no means had been found of breaking them4 ,the destructibility or indestructibility of the ether cannot be considered from the same standpoint as that for matter1 either ideally or really4 ,not ideally1 because we are utterly without any mechanical conceptions of the substance upon which one can base either reason or analogy2 and not really1 because we have no experimental evidence as to its nature or mode of operation4 ,if it be continuous1 there are no interspaces1 and if it be illimitable there is no unfilled space anywhere4 ,furthermore1 one might infer that if in any way a portion of the ether could be annihilated1 what was left would at once fill up the vacated space1 so there would be no record left of what had happened4 ,apparently1 its destruction would be the destruction of a substance1 which is a very different thing from the destruction of a mode of motion4 ,in the latter1 only the form of the motion need be destroyed to completely obliterate every trace of the atom4 ,in the former1 there would need to be the destruction of both substance and energy1 for it is certain1 for reasons yet to be attended to1 that the ether is saturated with energy4 ,one may1 without mechanical difficulties1 imagine a vortex-ring destroyed4 ,it is quite different with the ether itself1 for if it were destroyed in the same sense as the atom of matter1 it would be changed into something else which is not ether1 a proposition which assumes the existence of another entity1 the existence for which is needed only as a mechanical antecedent for the other4 ,the same assumption would be needed for this entity as for the ether1 namely1 something out of which it was made1 and this process of assuming antecedents would be interminable4 ,the last one considered would have the same difficulties to meet as the ether has now4 ,the assumption that it was in some way and at some time created is more rational1 and therefore more probable1 than that it either created itself or that it always existed4 ,considered as the underlying stratum of matter1 it is clear that changes of any kind in matter can in no way affect the quantity of ether4 #ag4 ,,matter ,,has ,,inertia4 ,the resistance that a mass of matter opposes to a change in its position or rate and direction of movement1 is called inertia4 ,that it should actively oppose anything has been already pointed out as reason for denying that matter is inert1 but inertia is the measure of the reaction of a body when it is acted upon by pressure from any source tending to disturb its condition of either rest or motion4 ,it is the equivalent of mass1 or the amount of matter as measured by gravity1 and is a fixed quantity2 for inertia is as inherent as any other quality1 and belongs to the ultimate atoms and every combination of them4 ,it implies the ability to absorb energy1 for it requires as much energy to bring a moving body to a standstill as was required to give it its forward motion4 ,both rotary and vibratory movements are opposed by the same property4 ,a grindstone1 a tuning-fork1 and an atom of hydrogen require1 to move them in their appropriate ways1 an amount of energy proportionate to their mass or inertia1 which energy is again transformed through friction into heat and radiated away4 ,one may say that inertia is the measure of the ability of a body to transfer or transform mechanical energy4 ,the meteorite that falls upon the earth to-day gives1 on its impact1 the same amount of energy it would have given if it had struck the earth ten thousand years ago4 ,the inertia of the meteor has persisted1 not as energy1 but as a factor of energy4 ,we commonly express the energy of a mass of matter by mv#b_/b1 where m stands for the mass and v for its velocity4 ,we might as well1 if it were as convenient1 substitute inertia for mass1 and write the expression iv#b_/b1 for the mass1 being measured by its inertia1 is only the more common and less definitive word for the same thing4 ,the energy of a mass of matter is1 then1 proportional to its inertia1 because inertia is one of its factors4 ,energy has often been treated as if it were an objective thing1 an entity and a unity2 but such a conception is evidently wrong1 for1 as has been said before1 it is a product of two factors1 either of which may be changed in any degree if the other be changed inversely in the same degree4 ,a cannon ball weighing #ajjj pounds1 and moving #ajj feet per second1 will have #aef1jjj foot-pounds of energy1 but a musket ball weighing an ounce will have the same amount when its velocity is #ab1fjj feet per second4 ,nevertheless1 another body acting upon either bullet or cannon ball1 tending to move either in some new direction1 will be as efficient while those bodies are moving at any assignable rate as when they are quiescent1 for the change in direction will depend upon the inertia of the bodies1 and that is constant4 ,the common theory of an inert body is one that is wholly passive1 having no power of itself to move or do anything1 except as some agency outside itself compels it to move in one way or another1 and thus endows it with energy4 ,thus a stone or an iron nail are thought to be inert bodies in that sense1 and it is true that either of them will remain still in one place for an indefinite time and move from it only when some external agency gives them impulse and direction4 ,still it is known that such bodies will roll down hill if they will not roll up1 and each of them has itself as much to do with the down-hill movement as the earth has2 that is1 it attracts the earth as much as the earth attracts it4 ,if one could magnify the structure of a body until the molecules became individually visible1 every one of them would be seen to be in intense activity1 changing its form and relative position an enormous number of times per second in undirected ways4 ,no two such molecules move in the same way at the same time1 and as all the molecules cohere together1 their motions in different directions balance each other1 so that the body as a whole does not change its position1 not because there is no moving agency in itself1 but because the individual movements are scattering1 and not in a common direction4 ,an army may remain in one place for a long time4 ,to one at a distance it is quiescent1 inert4 ,to one in the camp there is abundant sign of activity1 but the movements are individual movements1 some in one direction and some in another1 and often changing4 ,the same army on the march has the same energy1 the same rate of individual movement2 but all have a common direction1 it moves as a whole body into new territory4 ,so with the molecules of matter4 ,in large masses they appear to be inert1 and to do nothing1 and to be capable of doing nothing4 ,that is only due to the fact that their energy is undirected1 not that they can do nothing4 ,the inference that if quiescent bodies do not act in particular ways they are inert1 and cannot act in any kind of a way1 is a wrong inference4 ,an illustration may perhaps make this point plainer4 ,a lump of coal will be still as long as anything if it be undisturbed4 ,indeed1 it has thus lain in a coal-bed for millions of years probably1 but if coal be placed where it can combine with oxygen1 it forthwith does so1 and during the process yields a large amount of energy in the shape of heat4 ,one pound of coal in this way gives out #ad1jjj heat units1 which is the equivalent of #aa1jjj1jjj foot-pounds of work1 and if it could be all utilized would furnish a horse-power for five and a half hours4 ,can any inert body weighing a pound furnish a horse-power for half a day8 ,and can a body give out what it has not got8 ,are gunpowder and nitro-glycerine inert8 ,are bread and butter and foods in general inert because they will not push and pull as a man or a horse may8 ,all have energy1 which is available in certain ways and not in others1 and whatever possesses energy available in any way is not an ideally inert body4 ,lastly1 how many inert bodies together will it take to make an active body8 ,if the question be absurd1 then all the phenomena witnessed in bodies1 large or small1 are due to the fact that the atoms are not inert1 but are immensely energetic1 and their inertia is the measure of their rates of exchanging energy4 ,,the ,,ether ,,is ,,conditionally ,,possessed ,,of ,,inertia4 ,a moving mass of matter is brought to rest by friction1 because it imparts its motion at some rate to the body it is in contact with4 ,generally the energy is transformed into heat1 but sometimes it appears as electrification4 ,friction is only possible because one or both of the bodies possess inertia4 ,that a body may move in the ether for an indefinite time without losing its velocity has been stated as a reason for believing the ether to be frictionless4 ,if it be frictionless1 then it is without inertia1 else the energy of the earth and of a ray of light would be frittered away4 ,a ray of light can only be transformed when it falls upon molecules which may be heated by it4 ,as the ether cannot be heated and cannot transform translational energy1 it is without inertia for such a form of motion and its embodied energy4 ,it is not thus with other forms of energy than the translational4 ,atomic and molecular vibrations are so related to the ether that they are transformed into waves1 which are conducted away at a definite rate4 ,this shows that such property of inertia as is possessed by the ether is selective and not like that of matter1 which is equally inertiative under all conditions4 ,similarly with electric and magnetic phenomena1 it is capable of transforming the energy which may reside as stress in the ether1 and other bodies moving in the space so affected meet with frictional resistance1 for they become heated if the motion be maintained4 ,on the other hand1 there is no evidence that the body which produced the electric or magnetic stress suffers any degree of friction on moving in precisely the same space4 ,a bar magnet rotating on its longitudinal axis does not disturb its own field1 but a piece of iron revolving near the magnet will not only become heated1 but will heat the stationary magnet4 ,much experimental work has been done to discover1 if possible1 the relation of a magnet to its ether field4 ,as the latter is not disturbed by the rotation of the magnet1 it has been concluded that the field does not rotate2 but as every molecule in the magnet has its own field independent of all the rest1 it is mechanically probable that each such field does vary in the rotation1 but among the thousands of millions of such fields the average strength of the field does not vary within measurable limits4 ,another consideration is that the magnetic field itself1 when moved in space1 suffers no frictional resistance4 ,there is no magnetic energy wasted through ether inertia4 ,these phenomena show that whether the ether exhibits the quality called inertia depends upon the kind of motion it has4 #ah4 ,,matter ,,is ,,magnetic4 ,the ordinary phenomenon of magnetism is shown by bringing a piece of iron into the neighbourhood of a so-called magnet1 where it is attracted by the latter1 and if free to move will go to and cling to the magnet4 ,a delicately suspended magnetic needle will be affected appreciably by a strong magnet at the distance of several hundred feet4 ,as the strength of such action varies inversely as the square of the distance from the magnet1 it is evident there can be no absolute boundary to it4 ,at a distance from an ordinary magnet it becomes too weak to be detected by our methods1 not that there is a limit to it4 ,it is customary to think of iron as being peculiarly endowed with magnetic quality1 but all kinds of matter possess it in some degree4 ,wood1 stone1 paper1 oats1 sulphur1 and all the rest1 are attracted by a magnet1 and will stick to it if the magnet be a strong one4 ,whether a piece of iron itself exhibits the property depends upon its temperature1 for near #gjj degrees it becomes as magnetically indifferent as a piece of copper at ordinary temperature4 ,oxygen1 too1 at #bjj degrees below the zero of ,centigrade adheres to a magnet like iron4 ,in this as in so many other particulars1 how a piece of matter behaves depends upon its temperature1 not that the essential qualities are modified in any degree1 but temperature interferes with atomic arrangement and aggregation1 and so disguises their phenomena4 ,as every kind of matter is thus affected by a magnet1 the manifestations differing but in degree1 it follows that all kinds of atoms--all the elements--are magnetic4 ,an inherent property in them1 as much so as gravitation or inertia2 apparently a quality depending upon the structure of the atoms themselves1 in the same sense as gravitation is thus dependent1 as it is not a quality of the ether4 ,an atom must1 then1 be thought of as having polarity1 different qualities on the two sides1 and possessing a magnetic field as extensive as space itself4 ,the magnetic field is the stress or pressure in the ether produced by the magnetic body4 ,this ether pressure produced by a magnet may be as great as a ton per square inch4 ,it is this pressure that holds an armature to the magnet4 ,as heat is a molecular condition of vibration1 and radiant energy the result of it1 so is magnetism a property of molecules1 and the magnetic field the temporary condition in the ether1 which depends upon the presence of a magnetic body4 ,we no longer speak of the wave-motion in the ether which results from heat1 as heat1 but call it radiation1 or ether waves1 and for a like reason the magnetic field ought not to be called magnetism4 ,,the ,,ether ,,is ,,non-,,magnetic4 ,a magnetic field manifests itself in a way that implies that the ether structure1 if it may be said to have any1 is deformed--deformed in such a sense that another magnet in it tends to set itself in the plane of the stress2 that is1 the magnet is twisted into a new position to accommodate itself to the condition of the medium about it4 ,the new position is the result of the reaction of the ether upon the magnet and ether pressure acting at right angles to the body that produced the stress4 ,such an action is so anomalous as to suggest the propriety of modifying the so-called third law of motion1 viz41 action and reaction are equal and opposite1 adding that sometimes action and reaction are at right angles4 ,there is no condition or property exhibited by the ether itself which shows it to have any such characteristic as attraction1 repulsion1 or differences in stress1 except where its condition is modified by the activities of matter in some way4 ,the ether itself is not attracted or repelled by a magnet2 that is1 it is not a magnetic body in any such sense as matter in any of its forms is1 and therefore cannot properly be called magnetic4 ,it has been a mechanical puzzle to understand how the vibratory motions called heat could set up light waves in the ether seeing that there is an absence of friction in the latter4 ,in the endeavour to conceive it1 the origin of sound-waves has been in mind1 where longitudinal air-waves are produced by the vibrations of a sounding body1 and molecular impact is the antecedent of the waves4 ,the analogy does not apply4 ,the following exposition may be helpful in grasping the idea of such transformation and change of energy from matter to the ether4 ,consider a straight bar permanent magnet to be held in the hand4 ,it has its north and south poles and its field1 the latter extending in every direction to an indefinite distance4 ,the field is to be considered as ether stress of such a sort as to tend to set other magnets in it in new positions4 ,if at a distance of ten feet there were a delicately-poised magnet needle1 every change in the position of the magnet held in the hand would bring about a change in the position of the needle4 ,if the position of the hand magnet were completely reversed1 so the south pole faced where the north pole faced before1 the field would have been completely reversed1 and the poised needle would have been pushed by the field into an opposite position4 ,if the needle were a hundred feet away1 the change would have been the same except in amount4 ,the same might be said if the two were a mile apart1 or the distance of the moon or any other distance1 for there is no limit to an ether magnetic field4 ,suppose the hand magnet to have its direction completely reversed once in a second4 ,the whole field1 and the direction of the stress1 would necessarily be reversed as often4 ,but this kind of change in stress is known by experiment to travel with the speed of light1 #ahf1jjj miles a second2 the disturbance due to the change of position of the magnet will therefore be felt in some degree throughout space4 ,in a second and a third of a second it will have reached the moon1 and a magnet there will be in some measure affected by it4 ,if there were an observer there with a delicate-enough magnet1 he could be witness to its changes once a second for the same reason one in the room could4 ,the only difference would be one of amount of swing4 ,it is therefore theoretically possible to signal to the moon with a swinging magnet4 ,suppose again that the magnet should be swung twice a second1 there would be formed two waves1 each one half as long as the first4 ,if it should swing ten times a second1 then the waves would be one-tenth of #ahf1jjj miles long4 ,if in some mechanical way it could be rotated #ahf1jjj times a second1 the wave would be but one mile long4 ,artificial ways have been invented for changing this magnet field as many as #ajj million times a second1 and the corresponding wave is less than a foot long4 ,the shape of a magnet does not necessarily make it weaker or stronger as a magnet1 but if the poles are near together the magnetic field is denser between them than when they are separated4 ,the ether stress is differently distributed for every change in the relative positions of the poles4 ,a common ,u-magnet1 if struck1 will vibrate like a tuning-fork1 and gives out a definite pitch4 ,its poles swing towards and away from each other at uniform rates1 and the pitch of the magnet will depend upon its size1 thickness1 and the material it is made of4 ,let ten or fifteen ohms of any convenient-sized wire be wound upon the bend of a commercial ,u-magnet4 ,let this wire be connected to a telephone in its circuit4 ,when the magnet is made to sound like a tuning-fork1 the pitch will be reproduced in the telephone very loudly4 ,if another magnet with a different pitch be allowed to vibrate near the former1 the pitch of the vibrating body will be heard in the telephone1 and these show that the changing magnetic field reacts upon the quiescent magnet1 and compels the latter to vibrate at the same rate4 ,the action is an ether action1 the waves are ether waves1 but they are relatively very long4 ,if the magnet makes #ejj vibrations a second1 the waves will be #cgb miles long1 the number of times #ejj is contained in #ahf1jjj miles4 ,imagine the magnet to become smaller and smaller until it was the size of an atom1 the one-fifty-millionth of an inch4 ,its vibratory rate would be proportionally increased1 and changes in its form will still bring about changes in its magnetic field4 ,but its magnetic field is practically limitless1 and the number of vibrations per second is to be reckoned as millions of millions2 the waves are correspondingly short1 small fractions of an inch4 ,when they are as short as the one-thirty-seven-thousandth of an inch1 they are capable of affecting the retina of the eye1 and then are said to be visible as red light4 ,if the vibratory rate be still higher1 and the corresponding waves be no more than one-sixty-thousandth of an inch long1 they affect the retina as violet light1 and between these limits there are all the waves that produce a complete spectrum4 ,the atoms1 then1 shake the ether in this way because they all have a magnetic hold upon the ether1 so that any disturbance of their own magnetism1 such as necessarily comes when they collide1 reacts upon the ether for the same reason that a large magnet acts thus upon it when its poles approach and recede from each other4 ,it is not a phenomenon of mechanical impact or frictional resistance1 since neither are possible in the ether4 #ai4 ,,matter ,,exists ,,in ,,several ,,states4 ,molecular cohesion exists between very wide ranges4 ,when strong1 so if one part of a body is moved the whole is moved in the same way1 without breaking continuity or the relative positions of the molecules1 we call the body a solid4 ,in a liquid1 cohesion is greatly reduced1 and any part of it may be deformed without materially changing the form of the rest4 ,the molecules are free to move about each other1 and there is no definite position which any need assume or keep4 ,with gases1 the molecules are without any cohesion1 each one is independent of every other one1 collides with and bounds away from others as free elastic particles do4 ,between impacts it moves in what is called its free path1 which may be long or short as the density of the gas be less or greater4 ,these differing degrees of cohesion depend upon temperature1 for if the densest and hardest substances are sufficiently heated they will become gaseous4 ,this is only another way of saying that the states of matter depend upon the amount of molecular energy present4 ,solid ice becomes water by the application of heat4 ,more heat reduces it to steam2 still more decomposes the steam molecules into oxygen and hydrogen molecules2 and lastly1 still more heat will decompose these molecules into their atomic state1 complete dissociation4 ,on cooling1 the process of reduction will be reversed until ice has been formed again4 ,cohesive strength in solids is increased by reduction of temperature1 and metallic rods become stronger the colder they are4 ,no distinction is now made between cohesion and chemical affinity1 and yet at low temperatures chemical action will not take place1 which phenomenon shows there is a distinction between molecular cohesion and molecular structure4 ,in molecular structure1 as determined by chemical activity1 the molecules and atoms are arranged in definite ways which depend upon the rate of vibrations of the components4 ,the atoms are set in definite positions to constitute a given molecule4 ,but atoms or molecules may cohere for other reasons1 gravitative or magnetic1 and relative positions would be immaterial4 ,in the absence of temperature1 a solid body would be solider and stronger than ever1 while a gaseous mass would probably fall by gravity to the floor of the containing vessel like so much dust4 ,the molecular structure might not be changed1 for there would be no agency to act upon it in a disturbing way4 ,,the ,,ether ,,has ,,no ,,corresponding ,,states4 ,degrees of density have already been excluded1 and the homogeneity and continuity of the ether would also exclude the possibility of different states at all comparable with such as belong to matter4 ,as for cohesion1 it is doubtful if the term ought to be applied to such a substance4 ,the word itself seems to imply possible separateness1 and if the ether be a single indivisible substance1 its cohesion must be infinite and is therefore not a matter of degree4 ,the ether has sometimes been considered as an elastic solid1 but such solidity is comparable with nothing we call solid in matter1 and the word has to be defined in a special sense in order that its use may be tolerated at all4 ,in addition to this1 some of the phenomena exhibited by it1 such as diffraction and double refraction1 are quite incompatible with the theory that the ether is an elastic solid4 ,the reasons why it cannot be considered as a liquid or gas have been considered previously4 ,the expression states of matter cannot be applied to the ether in any such sense as it is applied to matter1 but there is one sense when possibly it may be considered applicable4 ,let it be granted that an atom is a vortex-ring of ether in the ether1 then the state of being in ring rotation would suffice to differentiate that part of the ether from the rest1 and give to it a degree of individuality not possessed by the rest2 and such an atom might be called a state of ether4 ,in like manner1 if other forms of motion1 such as transverse waves1 circular and elliptical spirals1 or others1 exist in the ether1 then such movements give special character to the part thus active1 and it would be proper to speak of such states of the ether1 but even thus the word would not be used in the same sense as it is used when one speaks of the states of matter as being solid1 liquid1 and gaseous4 #bj4 ,,solid ,,matter ,,can ,,experience ,a ,,shearing ,,stress1 ,,liquids ,,and ,,gases ,,cannot4 ,a sliding stress applied to a solid deforms it to a degree which depends upon the stress and the degree of rigidity preserved by the body4 ,thus if the hand be placed upon a closed book lying on the table1 and pressure be so applied as to move the upper side of the book but not the lower1 the book is said to be subject to a shearing stress4 ,if the pressing hand has a twisting motion1 the book will be warped4 ,any solid may be thus sheared or warped1 but neither liquids nor gases can be so affected4 ,molecular cohesion makes it possible in the one1 and the lack of it1 impossible in the others4 ,the solid can maintain such a deformation indefinitely long1 if the pressure does not rupture its molecular structure4 ,,the ,,ether ,,can ,,maintain ,a ,,shearing ,,stress4 ,the phenomena in a magnetic field show that the stress is of such a sort as to twist into a new directional position the body upon which it acts as exhibited by a magnetic needle1 also as indicated by the transverse vibrations of the ether waves1 and again by the twist given to plane polarized light when moving through a magnetic field4 ,these are all interpreted as indicative of the direction of ether stress1 as being similar to a shearing stress in solid matter4 ,the fact has been adduced to show the ether to be a solid1 but such a phenomenon is certainly incompatible with a liquid or gaseous ether4 ,this kind of stress is maintained indefinitely about a permanent magnet1 and the mechanical pressure which may result from it is a measure of the strength of the magnetic field1 and may exceed a thousand pounds per square inch4 #ba4 ,,other ,,properties ,,of ,,matter4 ,there are many secondary qualities exhibited by matter in some of its forms1 such as hardness1 brittleness1 malleability1 colour1 etc41 and the same ultimate element may exhibit itself in the most diverse ways1 as is the case with carbon1 which exists as lamp-black1 charcoal1 graphite1 jet1 anthracite and diamond1 ranging from the softest to the hardest of known bodies4 ,then it may be black or colourless4 ,gold is yellow1 copper red1 silver white1 chlorine green1 iodine purple4 ,the only significance any or all of such qualities have for us here is that the ether exhibits none of them4 ,there is neither hardness nor brittleness1 nor colour1 nor any approach to any of the characteristics for the identification of elementary matter4 #bb4 ,,sensation ,,depends ,,upon ,,matter4 ,however great the mystery of the relation of body to mind1 it is quite true that the nervous system is the mechanism by and through which all sensation comes1 and that in our experience in the absence of nerves there is neither sensation nor consciousness4 ,the nerves themselves are but complex chemical structures2 their molecular constitution is said to embrace as many as #bj1jjj atoms1 chiefly carbon1 hydrogen1 oxygen1 and nitrogen4 ,there must be continuity of this structure too1 for to sever a nerve is to paralyze all beyond4 ,if all knowledge comes through experience1 and all experience comes through the nervous system1 the possibilities depend upon the mechanism each one is provided with for absorbing from his environment1 what energies there are that can act upon the nerves4 ,touch1 taste1 and smell imply contact1 sound has greater range1 and sight has the immensity of the universe for its field4 ,the most distant but visible star acts through the optic nerve to present itself to consciousness4 ,it is not the ego that looks out through the eyes1 but it is the universe that pours in upon the ego4 ,again1 all the known agencies that act upon the nerves1 whether for touch or sound or sight1 imply matter in some of its forms and activities1 to adapt the energy to the nervous system4 ,the mechanism for the perception of light is complicated4 ,the light acts upon a sensitive surface where molecular structure is broken up1 and this disturbance is in the presence of nerve terminals1 and the sensation is not in the eye but in the sensorium4 ,in like manner for all the rest2 so one may fairly say that matter is the condition for sensation1 and in its absence there would be nothing we call sensation4 ,,the ,,ether ,,is ,,insensible ,,to ,,nerves4 ,the ether is in great contrast with matter in this particular4 ,there is no evidence that in any direct way it acts upon any part of the nervous system1 or upon the mind4 ,it is probable that this lack of relation between the ether and the nervous system was the chief reason why its discovery was so long delayed1 as the mechanical necessities for it even now are felt only by such as recognize continuity as a condition for the transmission of energy of whatever kind it may be4 ,action at a distance contradicts all experience1 is philosophically incredible1 and is repudiated by every one who once perceives that energy has two factors--substance and motion4 ,the table given below presents a list of twenty-two of the known properties of matter contrasted with those exhibited by the ether4 ,in none of them are the properties of the two identical1 and in most of them what is true for one is not true for the other4 ,they are not simply different1 they are incomparable4 ,from the necessities of the case1 as knowledge has been acquired and terminology became essential for making distinctions1 the ether has been described in terms applicable to matter1 hence such terms as mass1 solidity1 elasticity1 density1 rigidity1 etc41 which have a definite meaning and convey definite mechanical conceptions when applied to matter1 but have no corresponding meaning and convey no such mechanical conceptions when applied to the ether4 ,it is certain that they are inappropriate1 and that the ether and its properties cannot be described in terms applicable to matter4 ,mathematical considerations derived from the study of matter have no advantage1 and are not likely to lead us to a knowledge of the ether4 ,only a few have perceived the inconsistency of thinking of the two in the same terms4 ,in his ,grammar of ,science1 ,prof4 ,karl ,pearson says1 ,we find that our sense-impressions of hardness1 weight1 colour1 temperature1 cohesion1 and chemical constitution1 may all be described by the aid of the motions of a single medium1 which itself is conceived to have no hardness1 weight1 colour1 temperature1 nor indeed elasticity of the ordinary conceptual type4 ,none of the properties of the ether are such as one would or could have predicted if he had had all the knowledge possessed by mankind4 ,every phenomenon in it is a surprise to us1 because it does not follow the laws which experience has enabled us to formulate for matter4 ,a substance which has none of the phenomenal properties of matter1 and is not subject to the known laws of matter1 ought not to be called matter4 ,ether phenomena and matter phenomena belong to different categories1 and the ends of science will not be conserved by confusing them1 as is done when the same terminology is employed for both4 ,there are other properties belonging to the ether more wonderful1 if possible1 than those already mentioned4 ,its ability to maintain enormous stresses of various kinds without the slightest evidence of interference4 ,there is the gravitational stress1 a direct pull between two masses of matter4 ,between two molecules it is immeasurably small even when close together1 but the prodigious number of them in a bullet brings the action into the field of observation1 while between such bodies as the earth and moon or sun1 the quantity reaches an astonishing figure4 ,thus if the gravitative tension due to the gravitative attraction of the earth and moon were to be replaced by steel wires connecting the two bodies to prevent the moon from leaving its orbit1 there would be needed four number ten steel wires to every square inch upon the earth1 and these would be strained nearly to the breaking point4 ,yet this stress is not only endured continually by this pliant1 impalpable1 transparent medium1 but other bodies can move through the same space apparently as freely as if it were entirely free4 ,in addition to this1 the stress from the sun and the more variable stresses from the planets are all endured by the same medium in the same space and apparently a thousand or a million times more would not make the slightest difference4 ,rupture is impossible4 ,electric and magnetic stresses1 acting parallel or at right angles to the other1 exist in the same space and to indefinite degrees1 neither modifying the direction nor amount of either of the others4 ,these various stresses have been computed to represent energy1 which if it could be utilized1 each cubic inch of space would yield five hundred horse-power4 ,it shows what a store-house of energy the ether is4 ,if every particle of matter were to be instantly annihilated1 the universe of ether would still have an inexpressible amount of energy left4 ,to draw at will directly from this inexhaustible supply1 and utilize it for the needs of mankind1 is not a forlorn hope4 ,the accompanying table presents these contrasting properties for convenient inspection4 ,,contrasted ,,properties ,,of ,,matter ,,and ,,the ,,ether4 ,,matter4 ,,ether4 #a4 ,discontinuous ,continuous #b4 ,limited ,unlimited #c4 ,heterogeneous ,homogeneous #d4 ,atomic ,non-atomic #e4 ,definite structure ,structureless #f4 ,gravitative ,gravitationless #g4 ,frictionable ,frictionless #h4 olotropic ,isotropic #i4 ,chemically selective ---- #aj4 ,harmonically related ---- #aa4 ,energy embodied ,energy endowed #ab4 ,energy transformer ,non-transformer #ac4 ,elastic ,elastic8 #ad4 ,density ,density8 #ae4 ,heatable ,unheatable #af4 ,indestructible8 ,indestructible #ag4 ,inertiative ,inertiative conditionally #ah4 ,magnetic ---- #ai4 ,variable states ---- #bj4 ,subject to shearing stress in solid ,shearing stress maintained #ba4 ,has ,secondary qualities ---- #bb4 ,sensation depends upon ,insensible to nerves ,,chapter ,,iii ,antecedents of ,electricity--,nature of what is transformed--,series of transformations for the production of light--,positive and negative ,electricity--,positive and negative twists--,rotations about a wire--,rotation of an arc--,ether a non-conductor--,electro-magnetic waves--,induction and inductive action--,ether stress and atomic position--,nature of an electric current--,electricity a condition1 not an entity4 ,so far as we have knowledge to-day1 the only factors we have to consider in explaining physical phenomena are3 7#a7 ,ordinary matter1 such as constitutes the substance of the earth1 and the heavenly bodies2 7#b7 the ether1 which is omnipresent2 and 7#c7 the various forms of motion1 which are mutually transformable in matter1 and some of which1 but not all1 are transformable into ether forms4 ,for instance1 the translatory motion of a mass of matter can be imparted to another mass by simple impact1 but translatory motion cannot be imparted to the ether1 and1 for that reason1 a body moving in it is not subject to friction1 and continues to move on with velocity undiminished for an indefinite time2 but the vibratory motion which constitutes heat is transformable into wave-motion in the ether1 and is transmitted away with the speed of light4 ,the kind of motion which is thus transformed is not even a to-and-fro swing of an atom1 or molecule1 like the swing of a pendulum bob1 but that due to a change of form of the atoms within the molecule1 otherwise there could be no such thing as spectrum analysis4 ,vibratory motion of the matter becomes undulatory motion in the ether4 ,the vibratory motion we call heat2 the wave-motion we call sometimes radiant energy1 sometimes light4 ,neither of these terms is a good one1 but we now have no others4 ,it is conceded that it is not proper to speak of the wave-motion in the ether as heat2 it is also admitted that the ether is not heated by the presence of the wave--or1 in other words1 the temperature of the ether is absolute zero4 ,matter only can be heated4 ,but the ether waves can heat other matter they may fall on2 so there are three steps in the process and two transformations--7#a7 vibrating matter2 7#b7 waves in the ether2 7#c7 vibration in other matter4 ,energy has been transferred indirectly4 ,what is important to bear in mind is1 that when a form of energy in matter is transformed in any manner so as to lose its characteristics1 it is not proper to call it by the same name after as before1 and this we do in all cases when the transformation is from one kind in matter to another kind in matter4 ,thus1 when a bullet is shot against a target1 before it strikes it has what we call mechanical energy1 and we measure that in foot-pounds2 after it has struck the target1 the transformation is into heat1 and this has its mechanical equivalent1 but is not called mechanical energy1 nor are the motions which embody it similar4 ,the mechanical ideas in these phenomena are easy to grasp4 ,they apply to the phenomena of the mechanics of large and small bodies1 to sound1 to heat1 and to light1 as ordinarily considered1 but they have not been applied to electric phenomena1 as they evidently should be1 unless it be held that such phenomena are not related to ordinary phenomena1 as the latter are to one another4 ,when we would give a complete explanation of the phenomena exhibited by1 say1 a heated body1 we need to inquire as to the antecedents of the manifestation1 and also its consequents4 ,where and how did it get its heat8 ,where and how did it lose it8 ,when we know every step of those processes1 we know all there is to learn about them4 ,let us undertake the same thing for some electrical phenomena4 ,first1 under what circumstances do electrical phenomena arise8 7#a7 ,mechanical1 as when two different kinds of matter are subject to friction4 7#b7 ,thermal1 as when two substances in molecular contact are heated at the junction4 7#c7 ,magnetic1 as when any conductor is in a changing magnetic field4 7#d7 ,chemical1 as when a metal is being dissolved in any solution4 7#e7 ,physiological1 as when a muscle contracts4 ,illustration3 ,,fig4 #e4--;,frictional electrical machine4 ,each of these has several varieties1 and changes may be rung on combinations of them1 as when mechanical and magnetic conditions interact4 7#a7 ,in the first case1 ordinary mechanical or translational energy is spent as friction1 an amount measurable in foot-pounds1 and the factors we know1 a pressure into a distance4 ,if the surface be of the same kind of molecules1 the whole energy is spent as heat1 and is presently radiated away4 ,if the surfaces are of unlike molecules1 the product is a compound one1 part heat1 part electrical4 ,what we have turned into the machine we know to be a particular mode of motion4 ,we have not changed the amount of matter involved2 indeed1 we assume1 without specifying and without controversy1 that matter is itself indestructible1 and the product1 whether it be of one kind or another1 can only be some form of motion4 ,whether we can describe it or not is immaterial2 but if we agree that heat is vibratory molecular motion1 and there be any other kind of a product than heat1 it too must also be some other form of motion4 ,so if one is to form a conception of the mechanical origin of electricity1 this is the only one he can have--transformed motion4 ,illustration3 ,,fig4 #f4--,thermo-pile4 ,illustration3 ,,fig4 #g4--;,dynamo4 7#b7 ,when heat is the antecedent of electricity1 as in the thermo-pile1 that which is turned into the pile we know to be molecular motion of a definite kind4 ,that which comes out of it must be some equivalent motion1 and if all that went in were transformed1 then all that came out would be transformed1 call it by what name we will and let its amount be what it may4 7#c7 ,when a conductor is moved in a magnetic field1 the energy spent is measurable in foot-pounds1 as before1 a pressure into a distance4 ,the energy appears in a new form1 but the quantity of matter being unchanged1 the only changeable factor is the kind of motion1 and that the motion is molecular is evident1 for the molecules are heated4 ,mechanical or mass motion is the antecedent1 molecular heat motion is the consequent1 and the way we know there has been some intermediate form is1 that heat is not conducted at the rate which is observed in such a case4 ,call it by what name one will1 some form of motion has been intermediate between the antecedent and the consequent1 else we have some other factor of energy to reckon with than ether1 matter and motion4 7#d7 ,in a galvanic battery1 the source of electricity is chemical action2 but what is chemical action8 ,simply an exchange of the constituents of molecules--a change which involves exchange of energy4 ,molecules capable of doing chemical work are loaded with energy4 ,the chemical products of battery action are molecules of different constitution1 with smaller amounts of energy as measured in calorics or heat units4 ,if the results of the chemical reaction be prevented from escaping1 by confining them to the cell itself1 the whole energy appears as heat and raises the temperature of the cell4 ,if a so-called circuit be provided1 the energy is distributed through it1 and less heat is spent in the cell1 but whether it be in one place or another1 the mass of matter involved is not changed1 and the variable factor is the motion1 the same as in the other cases4 ,the mechanical conceptions appropriate are the transformation of one kind of motion into another kind by the mechanical conditions provided4 ,illustration3 ,,fig4 #h4--;,galvanic ,battery4 7#e7 ,physiological antecedents of electricity are exemplified by the structure and mode of operation of certain muscles 7,fig4 #i1 a7 in the torpedo and other electrical animals4 ,the mechanical contraction of them results in an electrical excitation1 and1 if a proper circuit be provided1 in an electric current4 ,the energy of a muscle is derived from food1 which is itself but a molecular compound loaded with energy of a kind available for muscular transformation4 ,bread-and-butter has more available energy1 pound for pound1 than has coal1 and can be substituted for coal for running an engine4 ,it is not used1 because it costs so much more4 ,there is nothing different1 so far as the factors of energy go1 between the food of an animal and the food of an engine4 ,what becomes of the energy depends upon the kind of structure it acts on4 ,it may be changed into translatory1 and the whole body moves in one direction2 or into molecular1 and then appears as heat or electrical energy4 ,if one confines his attention to the only variable factor in the energy in all these cases1 and traces out in each just what happens1 he will have only motions of one sort or another1 at one rate or another1 and there is nothing mysterious which enters into the processes4 ,we will turn now to the mode in which electricity manifests itself1 and what it can do4 ,it may be well to point out at the outset what has occasionally been stated1 but which has not received the philosophical attention it deserves--namely1 that electrical phenomena are reversible2 that is1 any kind of a physical process which is capable of producing electricity1 electricity is itself able to produce4 ,thus to name a few3 ,if mechanical motion develops electricity1 electricity will produce mechanical motion2 the movement of a pith ball and an electric motor are examples4 ,if chemical action can produce it1 it will produce chemical action1 as in the decomposition of water and electro-plating4 ,as heat may be its antecedent1 so will it produce heat4 ,if magnetism be an antecedent factor1 magnetism may be its product4 ,what is called induction may give rise to it in an adjacent conductor1 and1 likewise1 induction may be its effect4 ,illustration3 ,,fig4 #i4--,torpedo4 ,illustration3 ,,fig4 #aj4--;,dynamo and ,motor4 ,let us suppose ourselves to be in a building in which a steam-engine is at work4 ,there is fuel1 the furnace1 the boiler1 the pipes1 the engine with its fly-wheel turning4 ,the fuel burns in the furnace1 the water is superheated in the boiler1 the steam is directed by the pipes1 the piston is moved by the steam pressure1 and the fly-wheel rotates because of proper mechanism between it and the piston4 ,no one who has given attention to the successive steps in the process is so puzzled as to feel the need of inventing a particular force1 or a new kind of matter1 or any agency1 at any stage of the process1 different from the simple mechanical ones represented by a push or a pull4 ,even if he cannot see clearly how heat can produce a push1 he does not venture to assume a genii to do the work1 but for the time is content with saying that if he starts with motion in the furnace and stops with the motion of the fly-wheel1 any assumption of any other factor than some form of motion between the two would be gratuitous4 ,he can truthfully say that he understands the nature of that which goes on between the furnace and the wheel2 that it is some sort of motion1 the particular kind of which he might make out at his leisure4 ,suppose once more that1 across the road from an engine-house1 there was another building1 where all sorts of machines--lathes1 planers1 drills1 etc4--were running1 but that the source of the power for all this was out of sight1 and that one could see no connection between this and the engine on the other side of the street4 ,would one need to suppose there was anything mysterious between the two--a force1 a fluid1 an immaterial something8 ,this question is put on the supposition that one should not be aware of the shaft that might be between the two buildings1 and that it was not obvious on simple inspection how the machines got their motions from the engine4 ,no one would be puzzled because he did not know just what the intervening mechanism might be4 ,if the boiler were in the one building1 and the engine in the other with the machines1 he could see nothing moving between them1 even if the steam-pipes were of glass4 ,if matter of any kind were moving1 he could not see it there4 ,he would say there must be something moving1 or pressure could not be transferred from one place to the other4 ,substitute for the furnace and boiler a galvanic battery or a dynamo2 for the machines of the shop1 one or more motors with suitable wire connections4 ,when the dynamo goes the motors go2 when the dynamo stops the motors stop2 nothing can be seen to be turning or moving in any way between them4 ,is there any necessity for assuming a mysterious agency1 or a force of a nature different from the visible ones at the two ends of the line8 ,is it not certain that the question is1 ,how does the motion get from one to the other1 whether there be a wire or not8 ,if there be a wire1 it is plain that there is motion in it1 for it is heated its whole length1 and heat is known to be a mode of motion1 and every molecule which is thus heated must have had some antecedent motions4 ,whether it be defined or not1 and whether it be called by one name or another1 are quite immaterial1 if one is concerned only with the nature of the action1 whether it be matter or ether1 or motion or abracadabra4 ,once more3 suppose we have a series of active machines4 7,fig4 #aa47 ,an arc lamp1 radiating light-waves1 gets its energy from the wire which is heated1 which in turn gets its energy from the electric current2 that from a dynamo1 the dynamo from a steam-engine2 that from a furnace and the chemical actions going on in it4 ,let us call the chemical actions ,a1 the furnace ,b1 the engine ,c1 the dynamo ,d1 the electric lamp ,e1 the ether waves ,f4 7,fig4 #ab47 ,illustration3 ,,fig4 #aa4 ,the product of the chemical action of the coal is molecular motion1 called heat in the furnace4 ,the product of the heat is mechanical motion in the engine4 ,the product of the mechanical motion is electricity in the dynamo4 ,the product of the electric current in the lamp is light-waves in the ether4 ,no one hesitates for an instant to speak of the heat as being molecular motion1 nor of the motions of the engine as being mechanical2 but when we come to the product of the dynamo1 which we call electricity1 behold1 nearly every one says1 not that he does not know what it is1 but that no one knows6 ,does any one venture to say he does not know what heat is1 because he cannot describe in detail just what goes on in a heated body1 as it might be described by one who saw with a microscope the movements of the molecules8 ,let us go back for a moment to the proposition stated early in this book1 namely1 that if any body of any magnitude moves1 it is because some other body in motion and in contact with it has imparted its motion by mechanical pressure4 ,therefore1 the ether waves at ,f 7,fig4 #aa7 imply continuous motions of some sort from ,a to ,f4 ,that they are all motions of ordinary matter from ,a to ,e is obvious1 because continuous matter is essential for the maintenance of the actions4 ,at ,e the motions are handed over to the ether1 and they are radiated away as light-waves4 ,illustration3 ,,fig4 #ab4 ,illustration3 ,,fig4 #ac4 ,a puzzling electrical phenomenon has been what has been called its duality-states1 which are spoken of as positive and negative4 ,thus1 we speak of the positive plate of a battery and the negative pole of a dynamo2 and another troublesome condition to idealize has been1 how it could be that1 in an electric circuit1 there could be as much energy at the most remote part as at the source4 ,but1 if one will take a limp rope1 #h or #aj feet long1 tie its ends together1 and then begin to twist it at any point1 he will see the twist move in a right-handed spiral on the one hand1 and in a left-handed spiral on the other1 and each may be traced quite round the circuit2 so there will be as much twist1 as much motion1 and as much energy in one part of the rope as in any other2 and if one chooses to call the right-handed twist positive1 and the left-handed twist negative1 he will have the mechanical phenomenon of energy-distribution and the terminology1 analogous to what they are in an electric conductor4 7,fig4 #ac47 ,are the cases more dissimilar than the mechanical analogy would make them seem to be8 ,are there any phenomena which imply that rotation is going on in an electric conductor8 ,there are4 ,an electric arc1 which is a current in the air1 and is1 therefore1 less constrained than it is in a conductor1 rotates4 ,especially marked is this when in front of the pole of a magnet2 but the rotation may be noticed in an ordinary arc by looking at it with a stroboscope disk1 rotated so as to make the light to the eye intermittent at the rate of four or five hundred per second4 ,a ray of plane polarized light1 parallel with a wire conveying a current1 has its plane of vibration twisted to the right or left1 as the current goes one way or the other through the wire1 and to a degree that depends upon the distance it travels2 not only so1 but if the ray be sent1 by reflection1 back through the same field1 it is twisted as much more--a phenomenon which convinces one that rotation is going on in the space through which the ray travels4 ,if the ether through which the ray be sent were simply warped or in some static stress1 the ray1 after reflection1 would be brought back to its original plane1 which is not the case4 ,this rotation in the ether is produced by what is going on in the wire4 ,the ether waves called light are interpreted to imply that molecules originate them by their vibrations1 and that there are as many ether waves per second as of molecular vibrations per second4 ,in like manner1 the implication is the same1 that if there be rotations in the ether they must be produced by molecular rotation1 and there must be as many rotations per second in the ether as there are molecular rotations that produce them4 ,the space about a wire carrying a current is often pictured as filled with whorls indicating this motion 7,fig4 #ad71 and one must picture to himself1 not the wire as a whole rotating1 but each individual molecule independently4 ,but one is aware that the molecules of a conductor are practically in contact with each other1 and that if one for any reason rotates1 the next one to it would1 from frictional action1 cause the one it touched to rotate in the opposite direction1 whereas1 the evidence goes to show that all rotation is in the same direction4 ,illustration3 ,,fig4 #ad4 ,how can this be explained mechanically8 ,recall the kind of action that constitutes heat1 that it is not translatory action in any degree1 but vibratory1 in the sense of a change of form of an elastic body1 and this1 too1 of the atoms that make up the molecule of whatever sort4 ,each atom is so far independent of every other atom in the molecule that it can vibrate in this way1 else it could not be heated4 ,the greater the amplitude of vibration1 the more free space to move in1 and continuous contact of atoms is incompatible with the mechanics of heat4 ,there must1 therefore1 be impact and freedom alternating with each other in all degrees in a heated body4 ,if1 in any way1 the atoms themselves were made to rotate1 their heat impacts not only would restrain the rotations1 but the energy also of the rotation motion would increase the vibrations2 that is1 the heat would be correspondingly increased1 which is what happens always when an electric current is in a conductor4 ,it appears that the cooler a body is the less electric resistance it has1 and the indications are that at absolute zero there is no resistance2 that is1 impacts do not retard rotation1 but it is also apparent that any current sent through a conductor at that temperature would at once heat it4 ,this is the same as saying that an electric current could not be sent through a conductor at absolute zero4 ,so far1 mechanical conceptions are in accordance with electrical phenomena1 but there are several others yet to be noted4 ,electrical phenomena has been explained as molecular or atomic phenomena1 and there is one more in that category which is well enough known1 and which is so important and suggestive1 that the wonder is its significance has not been seen by those who have sought to interpret electrical phenomena4 ,the reference is to the fact that electricity cannot be transmitted through a vacuum4 ,an electric arc begins to spread out as the density of the air decreases1 and presently it is extinguished4 ,an induction spark that will jump two or three feet in air cannot be made to bridge the tenth of an inch in an ordinary vacuum4 ,a vacuum is a perfect non-conductor of electricity4 ,is there more than one possible interpretation to this1 namely1 that electricity is fundamentally a molecular and atomic phenomenon1 and in the absence of molecules cannot exist8 ,one may say1 ,electrical action is not hindered by a vacuum1 which is true1 but has quite another interpretation than the implication that electricity is an ether phenomenon4 ,the heat of the sun in some way gets to the earth1 but what takes place in the ether is not heat-transmission4 ,there is no heat in space1 and no one is at liberty to say1 or think1 that there can be heat in the absence of matter4 ,when heat has been transformed into ether waves1 it is no longer heat1 call it by what name one will4 ,formerly1 such waves were called heat-waves2 no one1 properly informed1 does so now4 ,in like manner1 if electrical motions or conditions in matter be transformed1 no matter how1 it is no longer proper to speak of such transformed motions or conditions as electricity4 ,thus1 if electrical energy be transformed into heat1 no one thinks of speaking of the latter as electrical4 ,if the electrical energy be transformed into mechanical of any sort1 no one thinks of calling the latter electrical because of its antecedent4 ,if electrical motions be transformed into ether actions of any kind1 why should we continue to speak of the transformed motions or energy as being electrical8 ,electricity may be the antecedent1 in the same sense as the mechanical motion of a bullet may be the antecedent of the heat developed when the latter strikes the target2 and if it be granted that a vacuum is a perfect non-conductor of electricity1 then it is manifestly improper to speak of any phenomenon in the ether as an electrical phenomenon4 ,it is from the failure to make this distinction that most of the trouble has come in thinking on this subject4 ,some have given all their attention to what goes on in matter1 and have called that electricity2 others have given their attention to what goes on in the ether1 and have called that electricity1 and some have considered both as being the same thing1 and have been confounded4 ,let us consider what is the relation between an electrified body and the ether about it4 ,when a body is electrified1 the latter at the same time creates an ether stress about it1 which is called an electric field4 ,the ether stress may be considered as a warp in the distribution of the energy about the body 7,fig4 #ae71 by the new positions given to the molecules by the process of electrification4 ,it has been already said that the evidence from other sources is that atoms1 rather than molecules1 in larger masses1 are what affect the ether4 ,one is inclined to inquire for the evidence we have as to the constitution of matter or of atoms4 ,there is only one hypothesis to-day that has any degree of probability2 that is1 the vortex-ring theory1 which describes an atom as being a vortex-ring of ether in the ether4 ,it possesses a definite amount of energy in virtue of the motion which constitutes it1 and this motion differentiates it from the surrounding ether1 giving it dimensions1 elasticity1 momentum1 and the possibility of translatory1 rotary1 vibratory motions1 and combinations of them4 ,without going further into this1 it is sufficient1 for a mechanical conception1 that one should have so much in mind1 as it will vastly help in forming a mechanical conception of reactions between atoms and the ether4 ,an exchange of energy between such an atom and the ether is not an exchange between different kinds of things1 but between different conditions of the same thing4 ,next1 it should be remembered that all the elements are magnetic in some degree4 ,this means that they are themselves magnets1 and every magnet has a magnetic field unlimited in extent1 which can almost be regarded as a part of itself4 ,if a magnet of any size be moved1 its field is moved with it1 and if in any way the magnetism be increased or diminished1 the field changes correspondingly4 ,illustration3 ,,fig4 #ae4 ,assume a straight bar electro-magnet in circuit1 so that a current can be made intermittent1 say1 once a second4 ,when the circuit is closed and the magnet is made1 the field at once is formed and travels outwards at the rate of #ahf1jjj miles per second4 ,when the current stops1 the field adjacent is destroyed4 ,another closure develops the field again1 which1 like the other1 travels outwards2 and so there may be formed a series of waves in the ether1 each #ahf1jjj miles long1 with an electro-magnetic antecedent4 ,if the circuit were closed ten times a second1 the waves would be #ah1fjj miles long2 if #ahf1jjj times a second1 they would be but one mile long4 ,if #djj million of millions times a second1 they would be but the forty-thousandth of an inch long1 and would then affect the eye1 and we should call them light-waves1 but the latter would not differ from the first wave in any particular except in length4 ,as it is proved that such electro-magnetic waves have all the characteristics of light1 it follows that they must originate with electro-magnetic action1 that is1 in the changing magnetism of a magnetic body4 ,this makes it needful to assume that the atoms which originate waves are magnets1 as they are experimentally found to be4 ,but how can a magnet1 not subject to a varying current1 change its magnetic field8 ,the strength or density of a magnetic field depends upon the form of the magnet4 ,when the poles are near together1 the field is densest2 when the magnet is bent back to a straight bar1 the field is rarest or weakest1 and a change in the form of the magnet from a ,u-form to a straight bar would result in a change of the magnetic field within its greatest limits4 ,a few turns of wire--as has been already said--wound about the poles of an ordinary ,u-magnet1 and connected to an ordinary magnetic telephone1 will enable one1 listening to the latter1 to hear the pitch of the former loudly reproduced when the magnet is struck like a tuning-fork1 so as to vibrate4 ,this shows that the field of the magnet changes at the same rate as the vibrations4 ,assume that the magnet becomes smaller and smaller until it is of the dimensions of an atom1 say for an approximation1 the fifty-millionth of an inch4 ,it would still have its field2 it would still be elastic and capable of vibration1 but at an enormously rapid rate2 but its vibration would change its field in the same way1 and so there would be formed those waves in the ether1 which1 because they are so short that they can affect the eye1 we call light4 ,the mechanical conceptions are legitimate1 because based upon experiments having ranges through nearly the whole gamut as waves in ether4 ,the idea implies that every atom has what may be loosely called an electro-magnetic grip upon the whole of the ether1 and any change in the former brings some change in the latter4 ,lastly1 the phenomenon called induction may be mechanically conceived4 ,it is well known that a current in a conductor makes a magnet of the wire1 and gives it an electro-magnetic field1 so that other magnets in its neighbourhood are twisted in a way tending to set them at right angles to the wire4 ,also1 if another wire be adjacent to the first1 an electric current having an opposite direction is induced in it4 ,thus3 ,consider a permanent magnet ,a 7,fig4 #ae71 free to turn on an axis in the direction of the arrow4 ,if there be other free magnets1 ,b and ,c1 in line1 they will assume such positions that their similar poles all point one way4 ,let ,a be twisted to a position at right angles1 then ,b will turn1 but in the opposite direction1 and ,c in similar4 ,that is1 if ,a turn in the direction of the hands of a clock1 ,b and ,c will turn in opposite directions4 ,these are simply the observed movements of large magnets4 ,imagine that these magnets be reduced to atomic dimensions1 yet retaining their magnetic qualities1 poles and fields4 ,would they not evidently move in the same way and for the same reason8 ,if it be true1 that a magnet field always so acts upon another as to tend by rotation to set the latter into a certain position1 with reference to the stress in that field1 then1 wherever there is a changing magnetic field1 there the atoms are being adjusted by it4 ,illustration3 ,,fig4 #af4 ,suppose we have a line of magnetic needles free to turn1 hundreds or thousands of them1 but disarranged4 ,let a strong magnetic field be produced at one end of the line4 ,the field would be strongest and best conducted along the magnet line1 but every magnet in the line would be compelled to rotate1 and if the first were kept rotating1 the rotation would be kept up along the whole line4 ,this would be a mechanical illustration of how an electric current travels in a conductor4 ,the rotations are of the atomic sort1 and are at right angles to the direction of the conductor4 ,that which makes the magnets move is inductive magnetic ether stress1 but the advancing motion represents mechanical energy of rotation1 and it is this motion1 with the resulting friction1 which causes the heat in a conductor4 ,what is important to note is1 that the action in the ether is not electric action1 but more properly the result of electro-magnetic action4 ,whatever name be given to it1 and however it comes about1 there is no good reason for calling any kind of ether action electrical4 ,electric action1 like magnetic action1 begins and ends in matter4 ,it is subject to transformations into thermal and mechanical actions1 also into ether stress--right-handed or left-handed--which1 in turn1 can similarly affect other matter1 but with opposite polarities4 ,in his ,modern ,views of ,electricity1 ,prof4 ,o4 ,j4 ,lodge warns us1 quite rightly1 that perhaps1 after all1 there is no such thing as electricity--that electrification and electric energy may be terms to be kept for convenience2 but if electricity as a term be held to imply a force1 a fluid1 an imponderable1 or a thing which could be described by some one who knew enough1 then it has no degree of probability1 for spinning atomic magnets seem capable of developing all the electrical phenomena we meet4 ,it must be thought of as a condition and not as an entity4 ,,the ,,end ,richard ,clay ,sons1 ,limited1 ,london ,bungay4 ,,publications ,,of ,,the ,society for ,promoting ,christian ,knowledge4 ,,the ,,romance ,,of ,,science4 ,a series of books which shows that science has for the masses as great interest as1 and more edification than1 the romances of the day4 ,small ,post #hvo1 ,cloth boards4 ,coal1 and what we get from it4 ,by ,professor ,,raphael ,,meldola1 ,f4,r4,s41 ,f4,i4,c4 ,with several ,illustrations4 #bs4 #f;d4 ,colour ,measurement and ,mixture4 ,by ,,captain ,w4 ,,de ,w4 ,,abney1 ,c4,b41 ,r4,e4 ,with numerous ,illustrations4 #bs4 #f;d4 ,the ,making of ,flowers4 ,by the ,rev4 ,professor ,,george ,,henslow1 ,m4,a41 ,f4,l4,s4 ,with several ,illustrations4 #bs4 #f;d4 ,the ,birth and ,growth of ,worlds4 ,a ,lecture by ,professor ,a4 ,h4 ,,green1 ,m4,a41 ,f4,r4,s4 #as4 ,soap-,bubbles1 and the ,forces which ,mould ,them4 ,a course of ,lectures by ,c4 ,v4 ,,boys1 ,a4,r4,s4,m41 ,f4,r4,s4 ,with numerous ,diagrams4 #bs4 #f;d4 ,spinning ,tops4 ,by ,professor ,j4 ,,perry1 ,m4,e41 ,d4,sc41 ,f4,r4,s4 ,with numerous ,diagrams4 #bs4 #f;d4 ,our ,secret ,friends and ,foes4 ,by ,p4 ,f4 ,,frankland1 ,f4,r4,s4 ,with numerous ,illustrations4 ,new ,edition1 #cs4 ,diseases of ,plants4 ,by ,professor ,,marshall ,,ward1 ,m4,a41 ,f4,r4,s41 ,f4,l4,s4 ,with numerous ,illustrations4 #bs4 #f;d4 ,the ,story of a ,tinder-,box4 ,by the late ,,charles ,,meymott ,,tidy1 ,m4,b41 ,m4,s4 ,with numerous ,illustrations4 #bs4 ,time and ,tide4 ,a ,romance of the ,moon4 ,by ,sir ,,robert ,s4 ,,ball1 ,,ll4,d41 ,royal ,astronomer of ,ireland4 ,with ,illustrations4 ,third ,edition1 revised4 #bs4 #f;d4 ,the ,splash of a ,drop4 ,by ,professor ,a4 ,m4 ,,worthington1 ,f4,r4,s4 ,with numerous ,illustrations4 #as4 #f;d4 ,,natural ,,history ,,rambles4 ,fcap4 #hvo41 with numerous ,woodcuts1 ,cloth boards1 #bs4 #f;d4 each4 ,,in ,,search ,,of ,,minerals4 ,by the late ,d4 ,t4 ,,anstead1 ,m4,a41 ,f4,r4,s4 ,,lakes ,,and ,,rivers4 ,by ,c4 ,o4 ,,groom ,,napier1 ,f4,g4,s4 ,,lane ,,and ,,field4 ,by the late ,rev4 ,j4 ,g4 ,,wood1 ,m4,a41 ,author of ,man and his ,handiwork1 c4 ,,mountain ,,and ,,moor4 ,by ,j4 ,e4 ,,taylor1 ,f4,l4,s41 ,f4,g4,s41 ,editor of ,science-,gossip4 ,,ponds ,,and ,,ditches4 ,by ,m4 ,c4 ,,cooke1 ,m4,a41 ,,ll4,d4 ,,the ,,sea-,,shore4 ,by ,professor ,p4 ,,martin ,,duncan1 ,m4,b4 7,london71 ,f4,r4,s4 ,,the ,,woodlands4 ,by ,m4 ,c4 ,,cooke1 ,m4,a41 ,,ll4,d41 ,author of ,freaks and ,marvels of ,plant ,life1 c4 ,,underground4 ,by ,j4 ,e4 ,,taylor1 ,f4,l4,s41 ,f4,g4,s4 ,,heroes ,,of ,,science4 ,crown #hvo4 ,cloth boards1 #ds4 each4 ,,astronomers4 ,by ,e4 ,j4 ,c4 ,,morton1 ,b4,a4 ,with numerous diagrams4 ,,botanists1 ,,zoologists1 ,,and ,,geologists4 ,by ,professor ,p4 ,,martin ,,duncan1 ,f4,r4,s41 c4 ,,chemists4 ,by ,m4 ,m4 ,,pattison ,,muir1 ,esq41 ,f4,r4,s4,e4 ,with several diagrams4 ,,mechanicians4 ,by ,t4 ,c4 ,,lewis1 ,m4,a4 ,,physicists4 ,by ,w4 ,,garnett1 ,esq41 ,m4,a4 ,,manuals ,,of ,,health4 ,fcap4 #hvo1 #abh pp41 ,limp ,cloth1 price #as4 each4 ,,health ,,and ,,occupation4 ,by the late ,sir ,b4 ,w4 ,,richardson1 ,f4,r4,s41 ,m4,d4 ,,habitation ,,in ,,relation ,,to ,,health 7,the74 ,by ,f4 ,s4 ,b4 ,,chaumont1 ,m4,d41 ,f4,r4,s4 ,,notes ,,on ,,the ,,ventilation ,,and ,,warming ,,of ,,houses1 ,,churches1 ,,schools1 ,,and ,,other ,,buildings4 ,by the late ,,ernest ,h4 ,,jacob1 ,m4,a41 ,m4,d4 7,,oxon474 ,,on ,,personal ,,care ,,of ,,health4 ,by the late ,e4 ,a4 ,,parkes1 ,m4,d41 ,f4,r4,s4 ,,air1 ,,water1 ,,and ,,disinfectants4 ,by ,c4 ,h4 ,,aikman1 ,m4,a41 ,d4,sc41 ,f4,r4,s4,e4 ,,manuals ,,of ,,elementary ,,science4 ,foolscap #hvo1 #abh pp4 with ,illustrations1 ,limp ,cloth1 #as4 each4 ,,physiology4 ,by ,professor ,a4 ,,macalister1 ,,ll4,d41 ,m4,d41 ,f4,r4,s41 ,f4,s4,a4 ,,geology4 ,by the ,rev4 ,t4 ,g4 ,,bonney1 ,m4,a41 ,f4,g4,s4 ,,astronomy4 ,by ,w4 ,h4 ,,christie1 ,m4,a41 ,f4,r4,s4 ,,botany4 ,by the late ,professor ,,robert ,,bentley4 ,,zoology4 ,by ,,alfred ,,newton1 ,m4,a41 ,f4,r4,s41 ,professor of ,zoology in the ,university of ,cambridge4 ,new ,revised ,edition4 ,,matter ,,and ,,motion4 ,by the late ,j4 ,,clerk ,,maxwell1 ,m4,a41 ,trinity ,college1 ,cambridge4 ,,spectroscope 7,,the71 ,,and ,,its ,,work4 ,by the late ,,richard ,a4 ,,proctor4 ,,crystallography4 ,by ,,henry ,,palin ,,gurney1 ,m4,a41 ,clare ,college1 ,cambridge4 ,,electricity4 ,by the late ,prof4 ,,fleeming ,,jenkin4 ,,miscellaneous ,,publications4 s4 d4 ,animal ,creation 7,the74 ,a popular ,introduction to ,zoology4 ,by the late ,,thomas ,,rymer ,,jones1 ,f4,r4,s4 ,with #dhh ,woodcuts4 ,post #hvo4 ,cloth boards #g #f ,birds' ,nests and ,eggs4 ,with #aa coloured plates of ,eggs4 ,square #afmo4 ,cloth boards #c #j ,british ,birds in ,their ,haunts4 ,by the late ,rev4 ,c4 ,a4 ,,johns1 ,b4,a41 ,f4,l4,s4 ,with #aij engravings by ,wolf and ,whymper4 ,post #hvo4 ,cloth boards #f #j ,evenings at the ,microscope2 or1 ,researches among the ,minuter ,organs and ,forms of ,animal ,life4 ,by the late ,,philip ,h4 ,,gosse1 ,f4,r4,s4 ,a ,new ,edition1 revised by ,professor ,f4 ,,jeffrey ,,bell4 ,with numerous ,woodcuts4 ,post #hvo4 ,cloth boards #e #j ,fern ,portfolio 7,the74 ,by ,,francis ,g4 ,,heath1 ,author of ,where to find ,ferns1 c4 ,with #ae plates1 elaborately drawn life-size1 exquisitely coloured from ,nature1 and accompanied with descriptive text4 ,cloth boards #h #j ,fishes1 ,natural ,history of ,british3 their ,structure1 ,economic ,uses1 and ,capture by ,net and ,rod4 ,by the late ,,frank ,,buckland4 ,with numerous illustrations4 ,crown #hvo4 ,cloth boards #e #j ,flowers of the ,field4 ,by the late ,rev4 ,c4 ,a4 ,,johns1 ,b4,a41 ,f4,l4,s4 ,new edition1 with an ,appendix on ,grasses1 by ,c4 ,h4 ,,johns1 ,m4,a4 ,with numerous woodcuts4 ,post #hvo4 ,cloth boards #f #j ,forest ,trees 7,the7 of ,great ,britain4 ,by the late ,rev4 ,c4 ,a4 ,,johns1 ,b4,a41 ,f4,l4,s4 ,with #aej woodcuts4 ,post #hvo4 ,cloth boards #e #j ,freaks and ,marvels of ,plant ,life2 or1 ,curiosities of ,vegetation4 ,by ,m4 ,c4 ,,cooke1 ,m4,a41 ,,ll4,d4 ,with numerous illustrations4 ,post #hvo4 ,cloth boards #f #j ,man and his ,handiwork4 ,by the late ,rev4 ,j4 ,g4 ,,wood1 ,author of ,lane and ,field1 c4 ,with about #ejj illustrations4 ,large ,post #hvo4 ,cloth boards #g #f ,natural ,history of the ,bible 7,the74 ,by the ,rev4 ,,canon ,,tristram1 ,author of ,the ,land of ,israel1 c4 ,with numerous illustrations4 ,crown #hvo4 ,cloth boards #e #j ,nature and her ,servants2 or1 ,sketches of the ,animal ,kingdom4 ,by the ,rev4 ,,theodore ,,wood4 ,with numerous woodcuts4 ,large ,post #hvo4 ,cloth boards #d #j ,ocean 7,the74 ,by the late ,,philip ,h4 ,,gosse1 ,f4,r4,s41 ,author of ,evenings at the ,microscope4 ,with #ea illustrations and woodcuts4 ,post #hvo4 ,cloth boards #c #j ,our ,bird ,allies4 ,by the ,rev4 ,,theodore ,,wood4 ,with numerous illustrations4 ,fcap4 #hvo4 ,cloth boards #b #f ,our ,insect ,allies4 ,by the ,rev4 ,,theodore ,,wood4 ,with numerous illustrations4 ,fcap4 #hvo4 ,cloth boards #b #f ,our ,insect ,enemies4 ,by the ,rev4 ,,theodore ,,wood4 ,with numerous illustrations4 ,fcap4 #hvo4 ,cloth boards #b #f ,our ,island ,continent4 ,a ,naturalist's ,holiday in ,australia4 ,by ,j4 ,e4 ,,taylor1 ,f4,l4,s41 ,f4,g4,s4 ,with ,map4 ,fcap4 #hvo4 ,cloth boards #b #f ,our ,native ,songsters4 ,by ,,anne ,,pratt1 ,author of ,wild ,flowers4 ,with #gb coloured plates4 #afmo4 ,cloth boards #d #j ,romance of ,low ,life amongst ,plants4 ,facts and ,phenomena of ,cryptogamic ,vegetation4 ,by ,m4 ,c4 ,,cooke1 ,m4,a41 ,,ll4,d41 ,a4,l4,s4 ,with numerous woodcuts4 ,large post #hvo4 ,cloth boards #d #j ,selborne 7,the ,natural ,history of74 ,by the ,,rev4 ,,gilbert ,,white4 ,with ,frontispiece1 ,map1 and #ej woodcuts4 ,post #hvo4 ,cloth boards #b #f ,toilers in the ,sea4 ,by ,m4 ,c4 ,,cooke1 ,m4,a41 ,,ll4,d4 ,post #hvo4 ,with numerous illustrations4 ,cloth boards #e #j ,vegetable ,wasps and ,plant ,worms4 ,by ,m4 ,c4 ,,cooke1 ,m4,a4 ,illustrated4 ,post #hvo4 ,cloth boards #e #j ,wayside ,sketches4 ,by ,f4 ,,edward ,,hulme1 ,f4,l4,s ,with numerous illustrations4 ,crown #hvo4 ,cloth boards #e #j ,where to find ,ferns4 ,by ,,francis ,g4 ,,heath1 ,author of ,the ,fern ,portfolio1 c4 ,with numerous illustrations4 ,fcap4 #hvo4 ,cloth boards #a #f ,wild ,flowers4 ,by ,,anne ,,pratt1 ,author of ,our ,native ,songsters1 c4 ,with #aib coloured plates4 ,in two volumes4 #afmo4 ,cloth boards #h #j 99 99 99 99 99 ,,london3 ,,northumberland ,,avenue1 ,,charing ,,cross1 ,w4,c42 #dc1 ,,queen ,,victoria ,,street1 ,e4,c4 ,transcriber's ,note ,minor typographical corrections have been made without comment4 ,inconsistencies in hyphenation1 and the author's use of commas when writing large numbers1 have been retained4