,,light ,,science4 ,,london3 ,,printed ,,by ,,spottiswoode ,,and ,,co41 ,,new-,,street ,,square ,,and ,,parliament ,,street ,,light ,,science ,,for ,,leisure ,,hours4 ,a ,,series ,,of ,,familiar ,,essays ,,on ,,scientific ,,subjects1 ,,natural ,,phenomena1 c4 ,,by ,,richard ,a4 ,,proctor1 ,,author ,,of #8,,the ,,sun' #8,,other ,,worlds ,,than ,,ours' #8,,saturn' ,,etc4 #8,i bear you witness as ye bear to me1 ,time1 day1 night1 sun1 stars1 life1 death1 air1 sea1 earth4' ,swinburne4 ,,new ,,edition4 ,,london3 ,,longmans1 ,,green1 ,,and ,,co4 #ahhf4 ,,preface ,,to ,,the ,,fifth ,,edition4 ,in preparing this edition1 only those passages which have been shown by recent researches to be erroneous have been removed4 ,it has not been thought necessary1 or even desirable1 to modify the wording of ,essays 7by changes of tense or otherwise7 in such a way that1 as thus modified1 the ,essays might have appeared in #ahhd4 ,in many cases this would have been altogether misleading1 whereas1 with the dates prefixed to the several ,essays1 no misconceptions can arise4 ,,richard ,a4 ,,proctor4 ,,preface ,,to ,,second ,,edition4 ,this edition has been carefully revised1 and1 in parts1 considerably modified4 ,thus the ,essay on ,britain's ,coal ,cellars has been added1 and two ,essays on ,government ,aid to ,science have been removed4 ,i may mention that my views on the subject of the last-named ,essays have changed altogether since those ,essays were written--certain circumstances which have come under my observation having convinced me that more mischief than advantage would result from any wide scheme for securing ,government aid for scientific researches4 ,,richard ,a4 ,,proctor4 ,,london3 ,january #ahgc4 ,,preface ,,to ,,first ,,edition4 ,in preparing these ,essays1 my chief object has been to present scientific truths in a light and readable form--clearly and simply1 but with an exact adherence to the facts as ,i see them4 ,i have followed--here and always--the rule of trying to explain my meaning precisely as ,i should wish others to explain1 to myself1 matters with which ,i was unfamiliar4 ,hence ,i have avoided that excessive simplicity which some seem to consider absolutely essential in scientific essays intended for general perusal1 but which is often even more perplexing than a too technical style4 ,the chief rule ,i have followed1 in order to make my descriptions clear1 has been to endeavour to make each sentence bear one meaning1 and one only4 ,speaking as a reader1 and especially as a reader of scientific books1 ,i venture to express an earnest wish that this simple rule were never infringed1 even to meet the requirements of style4 ,it will hardly be necessary to mention that several of the shorter ,essays are rather intended to amuse than to instruct4 ,the ,essay on the influence which marriage has been supposed to exert on the death-rate is the one referred to by ,mr4 ,darwin at page #agf 7vol4 i47 of his #8,descent of ,man4' ,,richard ,a4 ,,proctor4 ,,london3 ,may #ahga4 ,,contents4 ,,page ,,strange ,,discoveries ,,respecting ,,the ,,aurora #a ,,the ,,earth ,a ,,magnet #ad ,,our ,,chief ,,time-,,piece ,,losing ,,time #cj ,,encke ,,the ,,astronomer #df ,,venus ,,on ,,the ,,sun',s ,,face #di ,,britain',s ,,coal ,,cellars #gb ,,the ,,secret ,,of ,,the ,,north ,,pole #ig ,,is ,,the ,,gulf ,,stream ,a ,,myth8 #aad ,,floods ,,in ,,switzerland #acc ,a ,,great ,,tidal ,,wave #ach ,,deep-,,sea ,,dredgings #adb ,,the ,,tunnel ,,through ,,mont ,,cenis #adh ,,tornadoes #aec ,,vesuvius #afg ,,the ,,earthquake ,,in ,,peru #ahi ,,the ,,greatest ,,sea-,,wave ,,ever ,,known #aid ,,the ,,usefulness ,,of ,,earthquakes #baa ,,the ,,forcing ,,power ,,of ,,rain #bbe ,a ,,shower ,,of ,,snow-,,crystals #bcj ,,long ,,shots #bcc ,,influence ,,of ,,marriage ,,on ,,the ,,death-,,rate #bch ,,the ,,topographical ,,survey ,,of ,,india #bdd ,a ,,ship ,,attacked ,,by ,a ,,sword-,,fish #bef ,,the ,,safety-,,lamp #bei ,,the ,,dust ,,we ,,have ,,to ,,breathe #bfe ,,photographic ,,ghosts #bfg ,,the ,,oxford ,,and ,,cambridge ,,rowing ,,styles #bfi ,,betting ,,on ,,horse ,,races3 ,,or1 ,,the ,,state ,,of ,,the ,,odds #bgd ,,squaring ,,the ,,circle #bhh ,a ,,new ,,theory ,,of ,,achilles' ,,shield #big ,,light ,,science ,,for ,,leisure ,,hours4 ,,strange ,,discoveries ,,respecting ,,the ,,aurora4 ,the brilliant streamers of coloured light which wave at certain seasons over the heavens have long since been recognised as among the most singular and impressive of all the phenomena which the skies present to our view4 ,there is something surpassingly beautiful in the appearance of the true #8auroral curtain4' ,fringed with coloured streamers1 it waves to and fro as though shaken by some unseen hand4 ,then from end to end there pass a succession of undulations1 the folds of the curtain interwrapping and forming a series of graceful curves4 ,suddenly1 and as by magic1 there succeeds a perfect stillness1 as though the unseen power which had been displaying the varied beauties of the auroral curtain were resting for a moment4 ,but even while the motion of the curtain is stilled we see its light mysteriously waxing and waning4 ,then1 as we gaze1 fresh waves of disturbance traverse the magic canopy4 ,startling coruscations add splendour to the scene1 while the noble span of the auroral arch1 from which the waving curtain seems to depend1 gives a grandeur to the spectacle which no words can adequately describe4 ,gradually1 however1 the celestial fires which have illuminated the gorgeous arch seem to die out4 ,the luminous zone breaks up4 ,the scene of the display becomes covered with scattered streaks and patches of ashen grey light1 which hang like clouds over the northern heavens4 ,then these in turn disappear1 and nothing remains of the brilliant spectacle but a dark smoke-like segment on the horizon4 ,such is the aurora as seen in arctic or antarctic regions1 where the phenomenon appears in its fullest beauty4 ,even in our own latitudes1 however1 strikingly beautiful auroral displays may sometimes be witnessed4 ,yet those who have seen the spectacle presented near the true home of the aurora1 recognise in other auroras a want of the fulness and splendour of colour which form the most striking features of the arctic and antarctic auroral curtains4 ,physicists long since recognised in the aurora a phenomenon of more than local1 of more even than terrestrial1 significance4 ,they learned to associate it with relations which affect the whole planetary scheme4 ,let us inquire how this had come about4 ,so long as men merely studied the appearances presented by the aurora1 so long1 in fact1 as they merely regarded the phenomenon as a local display1 they could form no adequate conception of its importance4 ,the circumstance which first revealed something of the true character of the aurora was one which seemed to promise little4 ,arago was engaged in watching from day to day1 and from year to year1 the vibrations of the magnetic needle in the ,paris ,observatory4 ,he traced the slow progress of the needle to its extreme westerly variation1 and watched its course as it began to retrace its way towards the true north4 ,he discovered the minute vibration which the needle makes each day across its mean position4 ,he noticed that this vibration is variable in extent1 and so he was led to watch it more closely4 ,thus he had occasion to observe more attentively than had yet been done the sudden irregularities which occasionally characterise the daily movements of the needle4 ,all this seems to have nothing to do with the auroral streamers2 but we now reach the important discovery which rewarded ,arago's patient watchfulness4 ,in ,january #ahai he published a statement to the effect that the sudden changes of the magnetic needle are often associated with the occurrence of an aurora4 ,i give the statement in his own words1 as translated by ,general ,sabine3--#8,auroras ought to be placed in the first rank among the causes which sometimes disturb the regular march of the diurnal changes of the magnetic needle4 ,these do not1 even in summer1 exceed a quarter of a degree1 but when an aurora appears1 the magnetic needle is often seen to move in a few instants over several degrees4' #8,during an aurora1#8 he adds1 #8one often sees in the northern region of the heavens luminous streamers of different colours shoot from all points of the horizon4 ,the point in the sky to which these streamers converge is precisely the point to which a magnetised needle suspended by its centre of gravity directs itself4444 ,it has1 moreover1 been shown that the concentric circular segments1 almost similar in form to the rainbow1 which are usually seen previous to the appearance of the luminous streamers1 have their two extremities resting on two parts of the horizon which are equally distant from the direction towards which the needle turns2 and the summit of each arc lies exactly in that direction4 ,from all this1 it appears1 incontestably1 that there is an intimate connection between the causes of auroras and those of terrestrial magnetism4' ,this strange hypothesis was1 at first1 much opposed by scientific men4 ,amongst others1 the late ,sir ,david ,brewster pointed out a variety of objections1 some of which appeared at first sight of great force4 ,thus1 he remarked that magnetic disturbances of the most remarkable character have often been observed when no aurora has been visible2 and he noticed certain peculiarities in the auroras observed near the polar regions1 which did not seem to accord with ,arago's view4 ,but gradually it was found that physicists had mistaken the character of the auroral display4 ,it appeared that the magnetic needle not only swayed responsively to auroras observable in the immediate neighbourhood1 but to auroras in progress hundreds or even thousands of miles away4 ,nay1 as inquiry progressed1 it was discovered that the needles in our northern observatories are swayed by influences associated even with the occurrence of auroras around the southern polar regions4 ,in fact1 not only have the difficulties pointed out 7very properly1 it need hardly be remarked7 by ,sir ,david ,brewster been wholly removed2 but it has been found that a much closer bond of sympathy exists between the magnetised needle and the auroral streamers than even ,arago had supposed4 ,it is not merely the case that while an auroral display is in progress the needle is subject to unusual disturbance1 but the movements of the needle are actually synchronous with the waving movements of the mysterious streamers4 ,an aurora may be in progress in the north of ,europe1 or even in ,asia or ,america1 and as the coloured banners wave to and fro1 the tiny needle1 watched by patient observers at ,greenwich or ,paris1 will respond to every phase of the display4 ,and ,i may notice in passing that two very interesting conclusions follow from this peculiarity4 ,first1 every magnetic needle over the whole earth must be simultaneously disturbed2 and secondly1 the auroral streamers which wave across the skies of one country must move synchronously with those which are visible in the skies of another country1 even though thousands of miles may separate the two regions4 ,but ,i must pass on to consider further the circumstances which give interest and significance to the strange discovery which is the subject of this paper4 ,could we only associate auroras with terrestrial magnetism1 we should still have done much to enhance the interest which the beautiful phenomenon is calculated to excite4 ,but when once this association has been established1 others of even greater interest are brought into recognition4 ,for terrestrial magnetism has been clearly shown to be influenced directly by the action of the sun4 ,the needle in its daily vibration follows the sun1 not indeed through a complete revolution1 but as far as the influence of other forces will permit4 ,this has been abundantly confirmed1 and is a fact of extreme importance in the theory of terrestrial magnetism4 ,wherever the sun may be1 either on the visible heavens or on that half of the celestial sphere which is at the moment beneath the horizon1 the end of the needle nearest to the sun makes an effort 7so to speak7 to point more directly towards the great ruling centre of the planetary scheme4 ,seeing1 then1 that the daily vibration of the needle is thus caused1 we recognise the fact that the disturbances of the daily vibration may be referred to some peculiarity of the solar action4 ,it was not1 therefore1 so surprising as many have supposed1 that the increase and diminution of these disturbances1 in a period of about eleven years1 should be found to correspond with the increase and diminution of the number of solar spots in a period of equal length4 ,we already begin to see1 then1 that auroras are associated in some mysterious way with the action of the solar rays4 ,the phenomenon which had been looked on for so many ages as a mere spectacle1 caused perhaps by some process in the upper regions of the air1 of a simply local character1 has been brought into the range of planetary phenomena4 ,as surely as the brilliant planets which deck the nocturnal skies are illuminated by the same orb which gives us our days and seasons1 so they are subject to the same mysterious influence which causes the northern banners to wave resplendently over the star-lit depths of heaven4 ,nay1 it is even probable that every flicker and coruscation of our auroral displays corresponds with similar manifestations upon every planet which travels round the sun4 ,it becomes1 then1 a question of exceeding interest to inquire what is the nature of the mysterious apparition which from time to time illuminates our skies4 ,we have learnt something of the laws according to which the aurora appears2 but what is its true nature8 ,what sort of light is that which illuminates the heavens8 ,is there some process of combustion going on in the upper regions of our atmosphere8 ,or are the auroral streamers electric or phosphorescent8 ,or1 lastly1 is the light simply solar light reflected from some substance which exists at an enormous elevation above the earth8 ,all these views have from time to time found supporters among scientific men4 ,it need hardly be said that what we now know of the association between auroral action and some form of solar disturbance1 would at once enable us to reject some of these hypotheses4 ,but we need not discuss the subject from this point of view1 because a mode of research has recently been rendered available which at once answers our inquiries as to the general character of any kind of light4 ,i proceed to consider the application of this method to the light from the auroral streamers4 ,the spectroscope1 or1 as we may term the instrument1 the #8light-sifter1' tells us of what nature an object which is a source of light may be4 ,if the object is a luminous solid or liquid1 the instrument converts its light into a rainbow-coloured streak4 ,if the object is a luminous vapour1 its light is converted into a few bright lines4 ,and lastly1 if the object is a luminous solid or liquid shining through any vapours1 the rainbow-coloured streak again makes its appearance1 but it is now crossed by dark lines1 corresponding to the vapours which surround the object and absorb a portion of its light4 ,but ,i must not omit to notice two circumstances which render the interpretation of a spectrum somewhat less simple than it would otherwise be4 ,in the first place1 if an object is shining by reflected light its spectrum is precisely similar to that of the object whose light illuminates it4 ,thus we cannot pronounce positively as to the nature of an object merely from the appearance of its spectrum1 unless we are quite certain that the object is self-luminous4 ,for example1 we observe the solar spectrum to be a rainbow-coloured streak crossed by a multitude of dark lines1 and we conclude accordingly that the sun is an incandescent globe shining through a complex vaporous atmosphere4 ,we feel no doubt on this point1 because we are absolutely certain that the sun is self-luminous4 ,again1 we observe the spectrum of the moon to be exactly similar to the solar spectrum1 only1 of course1 much less brilliant4 ,and here also we feel no doubt in interpreting the result4 ,we know1 certainly1 that the moon is not self-luminous1 and therefore we conclude with the utmost certainty that the light we receive from her is simply reflected solar light4 ,so far all is clear4 ,but now take the case of an object like a comet1 which may or may not be self-luminous4 ,if we find that a comet's spectrum resembles the sun's--and this is not altogether a hypothetical case1 for a portion of the light of every comet yet examined does in reality give a rainbow-coloured streak resembling the solar spectrum--we cannot form1 in that case1 any such positive conclusion4 ,the comet may be a self-luminous body2 but1 on the other hand1 its light may be due merely to the reflection of the solar beams4 ,accordingly1 the spectroscopist always accompanies the record of such an observation with an expression of doubt as to the real nature of the object which is the source of light4 ,secondly1 when an electric spark flashes through any vapour1 its light gives a spectrum which indicates the nature1 not only of the vapour through which the spark has passed1 but of the substances between which the spark has travelled4 ,thus1 if we cause an electric flash to pass between iron points through common air1 we see in the spectrum the numerous bright lines which form the spectrum of iron1 and in addition we see the bright lines belonging to the gases which form our atmosphere4 ,both the considerations above discussed are of the utmost importance in studying the subject of the auroral light as analysed by the spectroscope1 because there are many difficulties in forming a general opinion as to the nature of the auroral light1 while there are circumstances which would lead us to anticipate that the light is electric4 ,i notice also in passing that we owe to the ,swedish physicist ngstrm a large share of the researches on which the above results respecting the spectrum of the electric spark are founded4 ,the reader will presently see why ,i have brought ngstrm's name prominently forward in connection with the interesting branch of spectroscopic analysis just referred to4 ,if the discovery we are approaching had been effected by a tyro in the use of the spectroscope1 doubts might very reasonably have been entertained respecting the exactness of the observations on which the discovery rests4 ,it was suggested many years ago1 long indeed before the true powers of spectroscopic analysis had been revealed1 that perhaps if the light of the aurora were analysed by the prism1 evidence could be obtained of its electric nature4 ,the eminent meteorologist ,dov remarked1 for instance1 that #8the peculiarities presented by the electric light are so marked that it appears easy to decide definitely by prismatic analysis whether the light of the aurora is or is not electric4' ,singularly enough1 however1 the first proof that the auroral light is of an electric nature was derived from a very different mode of inquiry4 ,dr4 ,robinson1 of ,armagh1 discovered in #aheh 7a year before ,kirchhoff's recognition of the powers of spectroscopic analysis7 that the light of the aurora possesses in a peculiar degree a property termed fluorescence1 which is a recognised and characteristic property of the light produced by electrical discharges4 #8,these effects1' he remarks of the appearances presented by the auroral light under the tests he applied1 #8were so strong in relation to the actual intensity of the light1 that they appear to afford an additional evidence of the electric origin of the phenomenon4' ,passing over this ingenious application of one of the most singular and interesting properties of light1 we find that the earliest determination of the real nature of the auroral light--or rather of its spectrum--was that effected by ngstrm4 ,this observer took advantage of the occurrence of a brilliant aurora in the winter of #ahfg-fh to analyse the spectrum of the coloured streamers4 ,a single bright line only was seen6 ,otto ,struve1 an eminent ,russian astronomer1 shortly afterwards made confirmatory observations4 ,at the meeting of the ,royal ,astronomical ,society in ,june1 #ahfh1 ,mr4 ,huggins thus described ,struve's results3--#8,in a letter1 ,m4 ,otto ,struve has informed me that he has had two good opportunities of observing the spectrum of the aurora borealis4 ,the spectrum consists of one line1 and the light is therefore monochromatic4 ,the line falls near the margin of the yellow and green portions of the spectrum4444 ,this shows that the monochromatic light is greenish1 which surprised me2 but ,general ,sabine tells me that in his polar expeditions he has frequently seen the aurora tinged with green1 and this appearance corresponds with the position of the line seen by ,m4 ,struve4' ,the general import of this observation there is no mistaking4 ,it teaches us that the light of the aurora is due to luminous vapour1 and we may conclude1 with every appearance of probability1 that the luminosity of the vapour is due to the passage of electric discharges through it4 ,it is1 however1 possible that the position of the bright line may be due to the character of the particles between which the discharges take place4 ,but the view we are to take must depend upon the position of the line4 ,here a difficulty presents itself4 ,there is no known terrestrial element whose spectrum has a bright line precisely in the position of the line in the auroral spectrum4 ,and mere proximity has no significance whatever in spectroscopic analysis4 ,two elements differing as much from each other in character as iron and hydrogen may have lines so closely approximating in position that only the most powerful spectroscope can indicate the difference4 ,so that when ngstrm remarks that the bright line he has seen lies slightly to the left of a well-known group of lines belonging to the metal calcium 7the principal ingredient of common chalk71 we are by no means to infer that he supposes the substance which causes the presence of the bright line has any resemblance to that element4 ,until we can find an element which has a bright line in its spectrum absolutely coincident with the bright line detected by ngstrm in the spectrum of the aurora1#a all speculation as to the real nature of the vapour in which the auroral electric discharge takes place1 or of the substances between which the spark travels1 is altogether precluded4 ,it was supposed after the total solar eclipse of #ahfi that the spectrum of the sun's corona exhibited the same bright lines as the aurora4 ,but recent observations show that the coincidence is not so close as had been supposed1 and1 in fact1 there is no evidence to show that the lines are the same4 7,from ,fraser's ,magazine1 ,february #ahgj47 ,,the ,,earth ,a ,,magnet4 ,there is a very prevalent but erroneous opinion that the magnetic needle points to the north4 ,i remember well how ,i discovered in my boyhood that the needle does not point to the north1 for the discovery was impressed upon me in a very unpleasant manner4 ,i had purchased a pocket-compass1 and was very anxious--not1 indeed1 to test the instrument1 since ,i placed implicit reliance upon its indications--but to make use of it as a guide across unknown regions4 ,not many miles from where ,i lived lay ,cobham ,wood1 no very extensive forest certainly1 but large enough to lose oneself in4 ,thither1 accordingly1 ,i proceeded with three schoolfellows4 ,when we had lost ourselves1 we gleefully called the compass into action1 and made from the wood in a direction which we supposed would lead us home4 ,we travelled on with full confidence in our pocket guide2 at each turning we consulted it in an artistic manner1 carefully poising it and waiting till its vibrations ceased4 ,but when we had travelled some two or three miles without seeing any house or road that we recognised1 matters assumed a less cheerful aspect4 ,we were unwilling to compromise our dignity as #8explorers' by asking the way--a proceeding which no precedent in the history of our favourite travellers allowed us to think of4 ,but evening came on1 and with it a summer thunder-storm4 ,we were getting thoroughly tired out1 and the hc olim meminisse juvabit with which we had been comforting ourselves began to lose its force4 ,when at length we yielded1 we learned that we had gone many miles out of our road1 and we did not reach home till several hours after dark4 ,also the offending compass was confiscated by justly indignant parents1 so that for a long while the cause of our troubles was a mystery to us4 ,in reality1 instead of pointing due north1 the compass pointed more than #bj towards the west1 or nearly to the quarter called by sailors north-north-west4 ,no wonder1 therefore1 that we went astray when we followed a guide so untrustworthy4 ,the peculiarity that the magnet needle does not1 in general1 point to the north1 is the first of a series of peculiarities which ,i now propose briefly to describe4 ,the irregularity is called by sailors the needle's variation1 but the term more commonly used by scientific men is the declination of the needle4 ,it was probably discovered a long time ago1 for #hjj years before our era the ,chinese applied the magnet's directive force to guide them in journeying over the great ,asiatic plains1 and they must soon have detected so marked a peculiarity4 ,instead of a ship's compass1 they made use of a magnetic car1 on the front of which a floating needle carried a small figure1 whose outstretched arm pointed southwards4 ,we have no record1 however1 of their discovery of the declination1 and know only that they were acquainted with it in the twelfth century4 ,the declination was discovered1 independently1 by ,european observers in the thirteenth century4 ,as we travel from place to place1 the declination of the needle is found to vary4 ,christopher ,columbus was the first to detect this4 ,he discovered it on the #acth of ,september1 #adib1 during his first voyage1 and when he was six hundred miles from ,ferro1 the most westerly of the ,canary ,islands4 ,he found that the declination1 which was towards the east in ,europe1 passed to the west1 and increased continually as he travelled westwards4 ,but here we see the first trace of a yet more singular peculiarity4 ,i have said that at present the declination is towards the west in ,europe4 ,in ,columbus's time it was towards the east4 ,thus we learn that the declination varies with the progress of time1 as well as with change of place4 ,the genius of modern science is a weighing and a measuring one4 ,men are not satisfied nowadays with knowing that a peculiarity exists2 they seek to determine its extent1 how far it is variable--whether from time to time or from place to place1 and so on4 ,now the results of such inquiries applied to the magnetic declination have proved exceedingly interesting4 ,we find1 first1 that the world may be divided into two unequal portions1 over one of which the needle has a westerly1 and over the other an easterly1 declination4 ,along the boundary line1 of course1 the needle points due north4 ,england is situated in the region of westerly magnets4 ,this region includes all ,europe1 except the north-eastern parts of ,russia2 ,turkey1 ,arabia1 and the whole of ,africa2 the greater part of the ,indian ,ocean1 and the western parts of ,australia2 nearly the whole of the ,atlantic ,ocean2 ,greenland1 the eastern parts of ,canada1 and a small slice from the north-eastern part of ,brazil4 ,all these form one region of westerly declination2 but1 singularly enough1 there lies in the very heart of the remaining and larger region of easterly magnets an oval space of a contrary character4 ,this space includes the ,japanese ,islands1 ,manchouria1 and the eastern parts of ,china4 ,it is very noteworthy also1 that in the westerly region the declination is much greater than in the easterly4 ,over the whole of ,asia1 for instance1 the needle points almost due north4 ,on the contrary1 in the north of ,greenland and of ,baffin's ,bay1 the magnetic needle points due west2 while still further to the north 7a little westerly71 we find the needle pointing with its north end directly towards the south4 ,in the presence of these peculiarities1 it would be pleasant to speculate4 ,we might imagine the existence of powerfully magnetic veins in the earth's solid mass1 coercing the magnetic needle from a full obedience to the true polar summons4 ,or the comparative effects of oceans and of continents might be called into play4 ,but unfortunately for all this1 we have to reconcile views founded on fixed relations presented by the earth with the process of change indicated above4 ,let us consider the declination in ,england alone4 ,in the fifteenth century there was an easterly declination4 ,this gradually diminished1 so that in about the year #afeg the needle pointed due north4 ,after this the needle pointed towards the west1 and continually more and more1 so that scientific men1 having had experience only of a continual shifting of the needle in one direction1 began to form the opinion that this change would continue1 so that the needle would pass1 through north-west and west1 to the south4 ,in fact1 it was imagined that the motion of the needle would resemble that of the hands of a watch1 only in a reversed direction4 ,but before long observant men detected a gradual diminution in the needle's westerly motion4 ,arago1 the distinguished ,french astronomer and physicist1 was the first 7,i believe7 to point out that #8the progressive movement of the magnetic needle towards the west appeared to have become continually slower of late years' 7he wrote in #ahad71 #8which seemed to indicate that after some little time longer it might become retrograde4' ,three years later1 namely1 on the #ajth of ,february1 #ahag1 ,arago asserted definitively that the retrograde movement of the magnetic needle had commenced to be perceptible4 ,colonel ,beaufoy at first oppugned ,arago's conclusion1 for he found from observations made in ,london1 during the years #ahag-ahai1 that the westerly motion still continued4 ,but he had omitted to take notice of the circumstance1 that ,london and ,paris are two different places4 ,a few years later the retrograde motion became perceptible at ,london also1 and it has now been established by the observations of forty years4 ,it appears1 from a careful comparison of ,beaufoy's observations1 that the needle reached the limit of its western digression 7at ,greenwich7 in ,march #ahai1 at which time the declination was very nearly #be4 ,in ,paris1 on the contrary1 the needle had reached its greatest western digression 7about #bb7 in #ahad4 ,it is rather singular that although at ,paris the retrograde motion thus presented itself five years earlier than in ,london1 the needle pointed due north at ,paris six years later than in ,london1 viz41 in #affc4 ,perhaps the greater amplitude of the needle's ,london digression may explain this peculiarity4 #8,it was already sufficiently difficult1' says ,arago1 #8to imagine what could be the kind of change in the constitution of the globe which could act during one hundred and fifty-three years in gradually transferring the direction of the magnetic needle from due north to #bc west of north4 ,we see that it is now necessary to explain1 moreover1 how it has happened that this gradual change has ceased1 and has given place to a return towards the preceding state of the globe4#8 #8,how is it1' he pertinently asks1 #8that the directive action of the globe1 which clearly must result from the action of molecules of which the globe is composed1 can be thus variable1 while the number1 position1 and temperature of these molecules1 and1 as far as we know1 all their other physical properties1 remain constant8' ,but we have considered only a single region of the earth's surface4 ,arago's opinion will seem still juster when we examine the change which has taken place in what we may term the #8magnetic aspect' of the whole globe4 ,the line which separates the region of westerly magnets from the region of easterly magnets now runs1 as we have said1 across ,canada and eastern ,brazil in one hemisphere1 and across ,russia1 ,asiatic ,turkey1 the ,indian ,ocean1 and ,west ,australia in the other1 besides having an outlying oval to the east of the ,asiatic continent4 ,these lines have swept round a part of the globe's circuit in a most singular manner since #afjj4 ,they have varied alike in direction and complexity4 ,the ,siberian oval1 now distinct1 was in #aghg merely a loop of the eastern line of no declination4 ,the oval appears now to be continually diminishing1 and will one day probably disappear4 ,we find here presented to us a phenomenon as mysterious1 as astonishing1 and as worthy of careful study as any embraced in the wide domains of science4 ,but other peculiarities await our notice4 ,if a magnetic needle of suitable length be carefully poised on a fine point1--or better1 be suspended from a silk thread without torsion1--it will be found to exhibit each day two small but clearly perceptible oscillations4 ,m4 ,arago1 from a careful series of observations1 deduced the following results3-- ,at about eleven at night1 the north end of the needle begins to move from west to east1 and having reached its greatest easterly excursion at about a quarter-past eight in the morning1 returns towards the west to attain its greatest westerly excursion at a quarter-past one4 ,it then moves again to the east1 and having reached its greatest easterly excursion at half-past eight in the evening1 returns to the west1 and attains its greatest westerly excursion at eleven1 as at starting4 ,of course1 these excursions take place on either side of the mean position of the needle1 and as the excursions are small1 never exceeding the fifth part of a degree1 while the mean position of the needle lies some #bj to the west of north1 it is clear that the excursions are only nominally eastern and western1 the needle pointing throughout1 far to the west4 ,now1 if we remember that the north end of the needle is that farthest from the sun1 it will be easy to trace in ,m4 ,arago's results a sort of effort on the part of the needle to turn towards the sun--not merely when that luminary is above the horizon1 but during his nocturnal path also4 ,we are prepared1 therefore1 to expect that a variation having an annual period1 shall appear1 on a close observation of our suspended needle4 ,such a variation has been long since recognised4 ,it is found that in the summer of both hemispheres1 the daily variation is exaggerated1 while in winter it is diminished4 ,but besides the divergence of a magnetised needle from the north pole1 there is a divergence from the horizontal position which must now claim our attention4 ,if a non-magnetic needle be carefully suspended so as to rest horizontally1 and be then magnetised1 it will be found no longer to preserve that position4 ,the northern end dips very sensibly4 ,this happens in our hemisphere4 ,in the southern1 it is the southern end which dips4 ,it is clear1 therefore1 that if we travel from one hemisphere to the other we must find the northern dip of the needle gradually diminishing1 till at some point near the equator the needle is horizontal2 and as we pass thence to southern regions1 a gradually increasing southern inclination is presented4 ,this has been found to be the case1 and the position of the line along which there is no inclination 7called the magnetic equator7 has been traced around the globe4 ,it is not coincident with the earth's equator1 but crosses that circle at an angle of twelve degrees1 passing from north to south of the equator in long4 #c west of ,greenwich1 and from south to north in long4 #ahg east of ,greenwich4 ,the form of the line is not exactly that of a great circle1 but presents here and there 7and especially where it crosses the ,atlantic7 perceptible excursions from such a figure4 ,at two points on the earth's globe the needle will rest in a vertical position4 ,these are the magnetic poles of the earth4 ,the northern magnetic pole was reached by ,sir ,j4 ,g4 ,ross1 and lies in #gj ,n4 lat4 and #bfc ,e4 long41 that is1 to the north of the ,american continent1 and not very far from ,boothia ,gulf4 ,one of the objects with which ,ross set out on his celebrated expedition to the ,antarctic ,seas was the discovery1 if possible1 of the southern magnetic pole4 ,in this he was not successful4 ,twice he was in hopes of attaining his object1 but each time he was stopped by a barrier of land4 ,he approached so near1 however1 to the pole1 that the needle was inclined at an angle of nearly ninety degrees to the horizon1 and he was able to assign to the southern pole a position in #ge ,s4 lat41 #aed ,e4 long4 ,it is not probable1 we should imagine1 that either pole is fixed1 since we shall now see that the inclination1 like the declination of the magnetic needle1 is variable from time to time1 as well as from place to place2 and in particular1 the magnetic equator is apparently subjected to a slow but uniform process of change4 ,arago tells us that the inclination of the needle at ,paris has been observed to diminish year by year since #afga4 ,at that time the inclination was no less than #ge2 in other words1 the needle was inclined only #ae to the vertical4 ,in #agia the inclination was less than #ga4 ,in #ahca it was less than #fh4 ,in like manner1 the inclination at ,london has been observed to diminish1 from #gb in #aghf to #gj in #ahjd1 and thence to #fh at the present time4 ,it might be anticipated from such changes as these that the magnetic equator would be found to be changing in position4 ,nay1 we can even guess in which way it must be changing4 ,for since the inclination is diminishing at ,london and ,paris1 the magnetic equator must be approaching these places1 and this 7in the present position of the curve7 can only happen by a gradual shifting of the magnetic equator from east to west along the true equator4 ,this motion has been found to be really taking place4 ,it is supposed that the movement is accompanied by a change of form1 but more observations are necessary to establish this interesting point4 ,can it be doubted that while these changes are taking place1 the magnetic poles also are slowly shifting round the true pole8 ,must not the northern pole1 for instance1 be further from ,paris now that the needle is inclined more than #bc from the vertical1 than in #afga1 when the inclination was only #ae8 ,it appears obvious that this must be so1 and we deduce the interesting conclusion that each of the magnetic poles is rotating around the earth's axis4 ,but there is another peculiarity of the needle which is as noteworthy as any of those ,i have mentioned4 ,i refer to the intensity of the magnetic action--the energy with which the needle seeks its position of rest4 ,this is not only variable from place to place1 but from time to time1 and is further subject to sudden changes of a very singular character4 ,it might be expected that where the dip is greater1 the directive energy of the magnet would be proportionately great4 ,and this is found to be approximately the case4 ,accordingly1 the magnetic equator is very nearly coincident with the #8equator of least intensity1' but not exactly4 ,as we approach the magnetic poles we find a more considerable divergence1 so that instead of there being a northern pole of greatest intensity nearly coincident with the northern magnetic pole1 which we have seen lies to the north of the ,american continent1 there are two northern poles1 one in ,siberia nearly at the point where the river ,lena crosses the ,arctic circle1 the other not so far to the north--only a few degrees north1 in fact1 of ,lake ,superior4 ,in the south1 in like manner1 there are also two poles1 one on the ,antarctic circle1 about #acj ,e4 long41 in ,adlie ,land1 the other not yet precisely determined1 but supposed to lie on about the #bdjth degree of longitude1 and south of the ,antarctic circle4 ,singularly enough1 there is a line of lower intensity running right round the earth along the valleys of the two great oceans1 #8passing through ,behring's ,straits and bisecting the ,pacific1 on one side of the globe1 and passing out of the ,arctic ,sea by ,spitsbergen and down the ,atlantic1 on the other4' ,colonel ,sabine discovered that the intensity of the magnetic action varies during the course of the year4 ,it is greatest in ,december and ,january in both hemispheres4 ,if the intensity had been greatest in winter1 one would have been disposed to have assigned seasonal variation of temperature as the cause of the change4 ,but as the epoch is the same for both hemispheres1 we must seek another cause4 ,is there any astronomical element which seems to correspond with the law discovered by ,sabine8 ,there is one very important element4 ,the position of the perihelion of the earth's orbit is such that the earth is nearest to the sun on about the #cast of ,december or the #ast of ,january4 ,there seems nothing rashly speculative1 then1 in concluding that the sun exercises a magnetic influence on the earth1 varying according to the distance of the earth from the sun4 ,nay1 ,sabine's results seem to point very distinctly to the law of variation4 ,for1 although the number of observations is not as yet very great and the extreme delicacy of the variation renders the determination of its amount very difficult1 enough has been done to show that in all probability the sun's influence varies according to the same law as gravity--that is1 inversely as the square of the distance4 ,that the sun1 the source of light and heat1 and the great gravitating centre of the solar system1 should exercise a magnetic influence upon the earth1 and that this influence should vary according to the same law as gravity1 or as the distribution of light and heat1 will not appear perhaps very surprising4 ,but the discovery by ,sabine that the moon exercises a distinctly traceable effect upon the magnetic needle seems to me a very remarkable one4 ,we receive very little light from the moon1 much less 7in comparison with the sun's light7 than most persons would suppose1 and we get absolutely no perceptible heat from her4 ,therefore it would seem rather to the influence of mass and proximity that the magnetic disturbances caused by the moon must be ascribed4 ,but if the moon exercises an influence in this way1 why should not the planets8 ,we shall see that there is evidence of some such influence being exerted by these bodies4 ,more mysterious1 if possible1 than any of the facts ,i have discussed is the phenomenon of magnetic storms4 ,the needle has been exhibiting for several weeks the most perfect uniformity of oscillation4 ,day after day1 the careful microscopic observation of the needle's progress has revealed a steady swaying to and fro1 such as may be seen in the masts of a stately ship at anchor on the scarce-heaving breast of ocean4 ,suddenly a change is noted2 irregular jerking movements are perceptible1 totally distinct from the regular periodic oscillations4 ,a magnetic storm is in progress4 ,but where is the centre of disturbance1 and what are the limits of the storm8 ,the answer is remarkable4 ,if the jerking movements observed in places spread over very large regions of the earth--and in some well-authenticated cases over the whole earth--be compared with the local time1 it is found that 7allowance being made for difference of longitude7 they occur precisely at the same instant4 ,the magnetic vibrations thrill in one moment through the whole frame of our earth6 ,but a very singular circumstance is observed to characterise these magnetic storms4 ,they are nearly always observed to be accompanied by the exhibition of the aurora in high latitudes1 northern and southern4 ,probably they never happen without such a display1 but numbers of auroras escape our notice4 ,the converse proposition1 however1 has been established as an universal one4 ,no great display of the aurora ever occurs without a strongly marked magnetic storm4 ,magnetic storms sometimes last for several hours or even days4 ,remembering the influence which the sun has been found to exercise upon the magnetic needle1 the question will naturally arise1 ,has the sun anything to do with magnetic storms8 ,we have clear evidence that he has4 ,on the #ast of ,september1 #ahei1 ,messrs4 ,carrington and ,hodgson were observing the sun1 one at ,oxford and the other in ,london4 ,their scrutiny was directed to certain large spots which1 at that time1 marked the sun's face4 ,suddenly a bright light was seen by each observer to break out on the sun's surface1 and to travel1 slowly in appearance1 but in reality at the rate of about #g1jjj miles in a minute1 across a part of the solar disc4 ,now it was found afterwards that the self-registering magnetic instruments at ,kew had made at that very instant a strongly marked jerk4 ,we learned1 also1 that at that moment a magnetic storm prevailed at the ,west ,indies1 in ,south ,america1 and in ,australia4 ,the signalmen in the telegraph stations at ,washington and ,philadelphia received strong electric shocks2 the pen of ,bain's telegraph was followed by a flame of fire2 and in ,norway the telegraphic machinery was set on fire4 ,at night great auroras were seen in both hemispheres4 ,it is impossible not to connect these startling magnetic indications with the remarkable appearance observed upon the sun's disc4 ,but there is other evidence4 ,magnetic storms prevail more commonly in some years than in others4 ,in those years in which they occur most frequently1 it is found that the ordinary oscillations of the magnetic needle are more extensive than usual4 ,now when these peculiarities had been noticed for many years1 it was found that there was an alternate and systematic increase and diminution in the intensity of magnetic action1 and that the period of the variation was about eleven years4 ,but at the same time1 a diligent observer had been recording the appearance of the sun's face from day to day and from year to year4 ,he had found that the solar spots are in some years more freely displayed than in others4 ,and he had determined the period in which the spots are successively presented with maximum frequency to be about eleven years4 ,on a comparison of the two sets of observations1 it was found 7and has now been placed beyond a doubt by many years of continued observation7 that magnetic perturbations are most energetic when the sun is most spotted1 and vice vers4 ,for so remarkable a phenomenon as this1 none but a cosmical cause can suffice4 ,we can neither say that the spots cause the magnetic storms nor that the magnetic storms cause the spots4 ,we must seek for a cause producing at once both sets of phenomena4 ,there is as yet no certainty in this matter1 but it seems as if philosophers would soon be able to trace in the disturbing action of the planets upon the solar atmosphere the cause as well of the marked period of eleven years as of other less distinctly marked periods which a diligent observation of solar phenomena is beginning to educe4 7,from the ,cornhill ,magazine1 ,june #ahfh47 ,,our ,,chief ,,time-,,piece ,,losing ,,time4 ,a distinguished ,french astronomer1 author of one of the most fascinating works on popular astronomy that has hitherto appeared1 remarks that a man would be looked upon as a maniac who should speak of the influence of ,jupiter's moons upon the cotton trade4 ,yet1 as he proceeds to show1 there is an easily traced connection between the ideas which appear at first sight so incongruous4 ,the link is found in the determination of celestial longitude4 ,similarly1 we should be disposed to wonder at an astronomer who1 regarding thoughtfully the stately motion of the sidereal system1 as exhibited on a magnified1 and1 therefore1 appreciable scale by a powerful telescope1 should speak of the connection between this movement and the intrinsic worth of a sovereign4 ,the natural thought with most men would be that #8too much learning' had made the astronomer mad4 ,yet1 when we come to inquire closely into the question of a sovereign's intrinsic value1 we find ourselves led to the diurnal motion of the stars1 and that by no very intricate path4 ,for1 ,what is a sovereign8 ,a coin containing so many grains of gold mixed with so many grains of alloy4 ,a grain1 we know1 is the weight of such and such a volume of a certain standard substance--that is1 so many cubic inches1 or parts of a cubic inch1 of that substance4 ,but what is an inch8 ,it is determined1 we find1 as a certain fraction of the length of a pendulum vibrating seconds in the latitude of ,london4 ,a second1 we know1 is a certain portion of a mean solar day1 and is practically determined by a reference to what is called a sidereal day--the interval1 namely1 between the successive passages by the same star of the celestial meridian of any fixed place4 ,this interval is assumed to be constant1 and it has1 indeed1 been described as the #8one constant element' known to astronomers4 ,we find1 then1 that there is a connection1 and a very important connection1 between the motion of the stars and our measures1 not merely of value1 but of weight1 length1 volume1 and time4 ,in fact1 our whole system of weights and measures is founded on the apparent diurnal motion of the sidereal system1 that is1 on the real diurnal rotation of the earth4 ,we may look on the meridian-plane in which the great transit-telescope of the ,greenwich ,observatory is made to swing1 as the gigantic hand of a mighty dial1 a hand which1 extending outwards among the stars1 traces out for us1 by its motion among them1 the exact progress of time1 and so gives us the means of weighing1 measuring1 and valuing terrestrial objects with an exactitude which is at present beyond our wants4 ,the earth1 then1 is our #8chief time-piece1' and it is of the correctness of this giant clock that ,i am now to speak4 ,but how can we test a time-piece whose motions we select to regulate every other time-piece8 ,if a man sets his watch every morning by the clock at ,westminster1 it is clearly impossible for him to test the accuracy of that clock by the motions of his watch4 ,it would1 indeed1 be possible to detect any gross change of rate2 but for the purpose of illustration ,i assume1 what is indeed the case1 that the clock is very accurate1 and therefore that minute errors only are to be looked for even in long intervals of time4 ,and just as the watch set by a clock cannot be made use of to test the clock for small errors1 so our best time-pieces cannot be employed to detect slow variations1 if any such exist1 in the earth's rotation-period4 ,sir ,william ,herschel1 who early saw the importance of the subject1 suggested another method4 ,some of the planets rotate in such a manner1 and bear such distinct marks upon their surface1 that it is possible1 by a series of observations extending over a long interval of time1 to determine the length of their rotation-period within a second or two4 ,supposing their rotation uniform1 we at once obtain an accurate measure of time4 ,supposing their rotation not uniform1 we obtain--7#a7 a hint of the kind of change we are looking for2 and 7#b71 by the comparison of two or more planets1 the means of guessing how the variation is to be distributed between the observed planets and our earth4 ,unfortunately1 it turned out that ,jupiter1 one of the planets from which ,herschel expected most1 does not afford us exact information-his real surface being always veiled by his dense and vapour-laden atmosphere4 ,saturn1 ,venus1 and ,mercury are similarly circumstanced1 and are in other respects unfavourable objects for this sort of observation4 ,mars only1 of all the planets1 is really available4 ,distinctly marked 7in telescopes of sufficient power7 with continents and oceans1 which are rarely concealed by vapours1 this planet is in other respects fortunately situated4 ,for it is certain that whatever variations may be taking place in planetary rotations must be due to external agencies4 ,now1 ,saturn and ,jupiter have their satellites to influence 7perhaps appreciably in long intervals of time7 their rotation-movements4 ,venus and ,mercury are near the sun1 and are therefore in this respect worse off than the earth1 whose rotation is in question4 ,mars1 on the other hand1 farther removed than we are from the sun1 having also no moon1 and being of small dimensions 7a very important point1 be it observed1 since the tidal action of the sun depends on the dimensions of a planet71 is likely to have a rotation-period all but absolutely constant4 ,herschel was rather unfortunate in his observations of ,mars4 ,having obtained a rough approximation from ,mars' rotation in an interval of two days--this rough approximation being1 as it chanced1 only thirty-seven seconds in excess of the true period1 he proceeded to take three intervals of one month each4 ,this should have given a much better value2 but1 as it happened1 the mean of the values he obtained was forty-six seconds too great4 ,he then took a period of two years1 and being misled by the erroneous values he had already obtained1 he missed one rotation1 getting a value two minutes too great4 ,thirty years ago1 two ,german astronomers1 ,beer and ,madler1 tried the same problem1 and taking a period of seven years1 obtained a value which exceeds the true value by only one second4 ,another ,german1 ,kaiser1 by combining more observations1 obtained a value which is within one-fifteenth of a second of the true value4 ,but a comparison of observations extending over #bjj years has enabled me to obtain a value which ,i consider to lie within one-hundredth part of a second of the truth4 ,this value for ,mars' rotation-period is #bd hours #cg minutes #bbgc seconds4 ,here1 then1 we have a result so accurate1 that at some future time it may serve to test the earth's rotation-period4 ,we have compared the rotation-rate of our test-planet with the earth's rate during the past #bjj years2 and therefore1 if the earth's rate vary by more than one-hundredth of a second in the next two or three hundred years1 we shall--or rather our descendants will--begin to have some notion of the change at the end of that time4 ,but in the meantime1 mankind being impatient1 and not willing to leave to a distant posterity any question which can possibly be answered now1 astronomers have looked around them for information available at once on this interesting point4 ,the search has not been in vain4 ,in fact1 we are able to announce1 with an approach to positiveness1 that our great terrestrial time-piece is actually losing time4 ,in our moon we have a neighbour which has long been in the habit of answering truthfully questions addressed to her by astronomers4 ,of old1 she told ,newton about gravitation1 and when he doubted1 and urged opposing evidence offered--as men in his time supposed--by the earth1 she set him on the right track1 so that when in due time the evidence offered by the earth was corrected1 ,newton was prepared at once to accept and propound the noble theory which rendered his name illustrious4 ,again1 men wished to learn the true shape of the earth1 and went hither and thither measuring its globe2 but the moon1 meanwhile1 told the astronomer who remained at home a truer tale4 ,they sought to learn the earth's distance from the sun1 and from this and that point they turned their telescopes on ,venus in transit2 but the moon set them nearer the truth1 and that not by a few miles1 but by #b1jjj1jjj miles or more4 ,we shall see that she has had something to say about our great terrestrial time-piece4 ,one of the great charms of the science of astronomy is1 that it enables men to predict4 ,at such and such an hour1 the astronomer is able to say1 a celestial body will occupy such and such a point on the celestial sphere4 ,you direct a telescope towards the point named1 and lo6 at the given instant1 the promised orb sweeps across the field of view4 ,each year there is issued a thick octavo volume crowded with such predictions1 three or four years in advance of the events predicted2 and these predictions are accepted with as little doubt by astronomers as if they were the records of past events4 ,but astronomers are not only able to predict--they can also trace back the paths of the celestial bodies1 and say3 #8,at such and such a long-past epoch1 a given star or planet occupied such and such a position upon the celestial sphere4' ,but how are they to verify such a statement8 ,it is clear that1 in general1 they cannot do so4 ,those who are able to appreciate 7or better1 to make use of7 the predictions of astronomy1 will1 indeed1 very readily accord a full measure of confidence to calculations of past events4 ,they know that astronomy is justly named the most exact of the sciences1 and they can see that there is nothing1 in the nature of things1 to render retrospection more difficult than prevision4 ,but there are hundreds who have no such experience of the exactness of modern astronomical methods--who have1 on the contrary1 a vague notion that modern astronomy is merely the successor of systems now exploded2 perhaps even that it may one day have to make way in its turn for new methods4 ,and if all other men were willing to accept the calculations of astronomers respecting long-past events1 astronomers themselves would be less easily satisfied4 ,long experience has taught them that the detection of error is the most fruitful source of knowledge2 therefore1 wherever such a course is possible1 they always gladly submit their calculations to the test of observation4 ,now1 looking backward into the far past1 it is only here and there that we see records which afford means of comparison with modern calculations4 ,the planets had swept on in their courses for ages with none to note them4 ,gradually1 observant men began to notice and record the more remarkable phenomena4 ,but such records1 made with very insufficient instrumental means1 had in general but little actual value3 it has been found easy to confirm them without any special regard to accuracy of calculation4 ,there is one class of phenomena1 however1 which no inaccuracy of observation can very greatly affect4 ,a total eclipse of the sun is an occurrence so remarkable1 that 7#a7 it can hardly take place without being recorded1 and 7#b7 a very rough record will suffice to determine the particular eclipse referred to4 ,long intervals elapse between successive total eclipses visible at the same place on the earth's surface1 and even partial eclipses of noteworthy extent occur but seldom at any assigned place4 ,very early1 therefore1 in the history of modern astronomy1 the suggestion was made1 that eclipses recorded by ancient historians should be calculated retrospectively4 ,an unexpected result rewarded the undertaking4 ,it was found that ancient eclipses could not be fairly accounted for without assigning a slower motion to the moon in long-past ages than she has at present6 ,here was a difficulty which long puzzled mathematicians4 ,one after another was foiled by it4 ,halley1 an ,english mathematician1 had detected the difficulty1 but no ,english mathematician was able to grapple with it4 ,contented with ,newton's fame1 they had suffered their ,continental rivals to shoot far ahead in the course he had pointed out4 ,but the best ,continental mathematicians were defeated4 ,in papers of acknowledged merit1 adorned by a variety of new processes1 and showing a deep insight into the question at issue1 they yet arrived1 one and all1 at the same conclusion--failure4 ,ninety years elapsed before the true explanation was offered by the great mathematician ,laplace4 ,a full exposition of his views would be out of place in such a paper as the present1 but1 briefly1 they amount to this3-- ,the moon travels in her orbit1 swayed chiefly by the earth's attraction4 ,but the sun1 though greatly more distant1 yet1 owing to the immensity of his mass1 plays an important part in guiding our satellite4 ,his influence tends to relieve the moon1 in part1 from the earth's sway4 ,thus she travels in a wider orbit1 and with a slower motion1 than she would have but for the sun's influence4 ,now the earth is not at all times equally distant from the sun1 and his influence upon the moon is accordingly variable4 ,in winter1 when the earth is nearest to the sun1 his influence is greatest4 ,the lunar month1 accordingly 7though the difference is very slight71 is longer in winter than in summer4 ,this variation had long been recognised as the moon's #8annual equation2' but ,laplace was the first to point out that the variation is itself slowly varying4 ,the earth's orbit is slowly changing in shape--becoming more and more nearly circular year by year4 ,as the greater axis of her orbit is unchanging1 it is clear that the actual extent of the orbit is slowly increasing4 ,thus1 the moon is slightly released from the sun's influence year by year1 and so brought more and more under the earth's influence4 ,she travels1 therefore1 continually faster and faster1 though the change is indeed but a very minute one2--only to be detected in long intervals of time4 ,also the moon's acceleration1 as the change is termed1 is only temporary1 and will in due time be replaced by an equally gradual retardation4 ,when ,laplace had calculated the extent of the change due to the cause he had detected1 and when it was found that ancient eclipses were now satisfactorily accounted for1 it may well be believed that there was triumph in the mathematical camp4 ,but this was not all4 ,other mathematicians attacked the same problem1 and their results agreed so closely that all were convinced that the difficulty was thoroughly vanquished4 ,a very noteworthy result followed from ,laplace's calculations4 ,amongst other solutions which had been suggested1 was the supposition 7supported by no less an authority than ,sir ,isaac ,newton1 who lived to see the commencement of the long conflict maintained by mathematicians with this difficulty71 that it is not the moon travelling more quickly1 but our earth rotating more slowly1 which causes the observed discrepancy4 ,now it resulted from ,laplace's labours--as he was the first to announce--that the period of the earth's rotation has not varied by one-tenth of a second per century in the last two thousand years4 ,the question thus satisfactorily settled1 as was supposed1 was shelved for more than a quarter of a century4 ,the result1 also1 which seemed to flow from the discussion--the constancy of the earth's rotation-movement--was accepted2 and1 as we have seen1 our national system of measures was founded upon the assumed constancy of the day's duration4 ,but mathematicians were premature in their rejoicings4 ,the question has been brought1 by the labours of ,professor ,adams--co-discoverer with ,leverrier of the distant ,neptune--almost exactly to the point which it occupied a century ago4 ,we are face to face with the very difficulties--somewhat modified in extent1 but not in character--which puzzled ,halley1 ,euler1 and ,lagrange4 ,it would be an injustice to the memory of ,laplace to say that his labours were thrown away4 ,the explanation offered by him is indeed a just one4 ,but it is insufficient4 ,properly estimated it removes only half the difficulty which had perplexed mathematicians4 ,it would be quite impossible to present in brief space1 and in form suited to these pages1 the views propounded by ,adams4 ,what1 for instance1 would most of our readers learn if we were to tell them that1 #8when the variability of the eccentricity is taken into account1 in integrating the differential equations involved in the problem of the lunar motions--that is1 when the eccentricity is made a function of the time--non-periodic or secular terms appear in the expression for the moon's mean motion'--and so on8 ,let it suffice to say that ,laplace had considered only the work of the sun in diminishing the earth's pull on the moon1 supposing that the slow variation in the sun's direct influence on the moon's motion in her orbit must be self-compensatory in long intervals of time4 ,adams has shown1 on the contrary1 that when this variation is closely examined1 no such compensation is found to take place2 and that the effect of this want of compensation is to diminish by more than one-half the effects due to the slow variation examined by ,laplace4 ,these views gave rise at first to considerable controversy4 ,pontcoulant characterised ,adams's processes as #8analytical conjuring-tricks1' and ,leverrier stood up gallantly in defence of ,laplace4 ,the contest swayed hither and thither for a while1 but gradually the press of new arrivals on ,adams's side began to prevail4 ,one by one his antagonists gave way2 new processes have confirmed his results1 figure for figure2 and no doubt now exists1 in the mind of any astronomer competent to judge1 of the correctness of ,adams's views4 ,but1 side by side with this inquiry1 another had been in progress4 ,a crowd of diligent labourers had been searching with close and rigid scrutiny into the circumstances attending ancient eclipses4 ,a new light had been thrown upon this subject by the labours of modern travellers and historians4 ,one remarkable instance of this may be cited4 ,mr4 ,layard has identified the site of ,larissa with the modern ,nimroud4 ,now1 ,xenophon relates that when ,larissa was besieged by the ,persians1 an eclipse of the sun took place1 so remarkable in its effects 7and therefore undoubtedly total71 that the ,median defenders of the town threw down their arms1 and the city was accordingly captured4 ,and ,hansen has shown that a certain estimate of the moon's motion makes the eclipse which occurred on ,august #ae1 #caj ,b4,c41 not only total1 but central at ,nimroud4 ,some other remarkable eclipses--as the celebrated sunset eclipse 7total7 at ,rome1 #cii ,b4,c42 the eclipse which enveloped the fleet of ,agathocles as he escaped from ,syracuse2 the famous eclipse of ,thales1 which interrupted a battle between the ,medes and ,lydians2 and even the partial eclipse which 7possibly7 caused the #8going back of the shadow upon the dial of ,ahaz'--have all been accounted for satisfactorily by ,hansen's estimate of the moon's motion3 so also have nineteen lunar eclipses recorded in the ,almagest4 ,this estimate of ,hansen's1 which accounts so satisfactorily for solar and lunar eclipses1 makes the moon's rate of motion increase more than twice as fast as it should do according to the calculations of ,adams4 ,but before our readers run away with the notion that astronomers have here gone quite astray1 it will be well to present1 in a simple manner1 the extreme minuteness of the discrepancy about which all the coil has been made4 ,suppose that1 just in front of our moon1 a false moon exactly equal to ours in size and appearance 7see note at the end of this paper7 were to set off with a motion corresponding to the present motion of the moon1 save only in one respect--namely1 that the false moon's motion should not be subject to the change we are considering1 termed the acceleration4 ,then one hundred years would elapse before our moon would fairly begin to show in advance4 ,she would1 in that time1 have brought only one one-hundred-and-fiftieth part of her breadth from behind the false moon4 ,at the end of another century she would have gained four times as much2 at the end of a third1 nine times as much3 and so on4 ,she would not fairly have cleared her own breadth in less than twelve hundred years4 ,but the whole of this gain1 minute as it is1 is not left unaccounted for by our modern astronomical theories4 ,half the gain is explained1 the other half remains to be interpreted2 in other words1 the moon travels further by about half her own breadth in twelve centuries than she should do according to the lunar theory4 ,but in this difficulty1 small as it seems1 we are not left wholly without resource4 ,we are not only able to say that the discrepancy is probably due to a gradual retardation of the earth's rotation-movement1 but we are able to place our finger on a very sufficient cause for such a retardation4 ,one of the most firmly established principles of modern science is this--that where work is done1 force is1 in some way or other1 expended4 ,the doing of work may show itself in a variety of ways-- in the generation of heat1 in the production of light1 in the raising of weights1 and so on2 but in every case an equivalent force must be expended4 ,if the brakes are applied to a train in motion1 intense heat is generated in the substance of the brake4 ,now1 the force employed by the brakesman is not equivalent to the heat generated4 ,where1 then1 is the balance of force expended8 ,we all know that the train's motion is retarded1 and this loss of motion represents the requisite expenditure of force4 ,now1 is there any process in nature resembling1 in however remote a degree1 the application of a brake to check the earth's rotation8 ,there is4 ,the tidal wave1 which sweeps1 twice a day1 round the earth1 travels in a direction contrary to the earth's motion of rotation4 ,that this wave #8does work1' no one can doubt who has watched its effects4 ,the mere rise and fall in open ocean may not be strikingly indicative of #8work done2' but when we see the behaviour of the tidal wave in narrow channels1 when we see heavily-laden ships swept steadily up our tidal rivers1 we cannot but recognise the expenditure of force4 ,now1 where does this force come from8 ,motion being the great #8force-measurer1' what motion suffers that the tides may work8 ,we may securely reply1 that the only motion which can supply the requisite force is the earth's motion of rotation4 ,therefore1 it is no mere fancy1 but a matter of absolute certainty1 that1 though slowly1 still very surely1 our terrestrial globe is losing its rotation-movement4 ,considered as a time-piece1 what are the earth's errors8 ,suppose1 for a moment1 that the earth was timed and rated two thousand years ago1 how much has she lost1 and what is her #8rate-error8' ,she has lost in that interval nearly one hour and a quarter1 and she is losing now at the rate of one second in twelve weeks4 ,in other words1 the length of a day is now more by about one eighty-fourth part of a second than it was two thousand years ago4 ,at this rate of change1 our day would merge into a lunar month in the course of thirty-six thousand millions of years4 ,but after a while1 the change will take place more slowly1 and some trillion or so of years will elapse before the full change is effected4 ,distant1 however1 as is the epoch at which the changes we have been considering will become effective1 the subject appears to us to have an interest apart from the mere speculative consideration of the future physical condition of our globe4 ,instead of the recurrence of ever-varying1 closely intermingled cycles of fluctuation1 we see1 now for the first time1 the evidence of cosmical decay--a decay which1 in its slow progress1 may be but the preparation for renewed genesis--but still1 a decay which1 so far as the races at present subsisting upon the earth are concerned1 must be looked upon as finally and completely destructive4#b 7,from ,chambers's ,journal1 ,october #ab1 #ahfg47 ,,encke ,,the ,,astronomer4 ,the years which have passed since ,encke died have witnessed notable changes in the aspect of the science he loved so well4 ,but we must look back over more than half a century1 if we would form an estimate of the position of astronomy when ,encke's most notable work was achieved4 ,at ,seeberge1 under ,lindenau1 ,encke had been perfecting himself in the higher branches of mathematical calculation4 ,he took the difficult work of determining the orbital motions of newly-discovered comets under his special charge1 and ,dr4 ,bruhns tells us that every comet which was detected during ,encke's stay at ,seeberge was subjected to rigid scrutiny by the indefatigable mathematician4 ,before long a discovery of the utmost importance rewarded his persevering labours4 ,pons had detected on ,november #bf1 #ahah1 a comet of no very brilliant aspect1 which was watched first at ,marseilles1 and then at ,mannheim1 until ,december #bi4 ,encke next took up the work1 and tracked the comet until ,january #ab4 ,combining the observations made between ,december #bb and ,january #ab1 he assigned to the body a parabolic orbit4 ,but he was not satisfied with the accordance between this path and the observed motions of the body4 ,when he attempted to account for the motions of the comet by means of an orbit of comparatively short period1 he was struck by the resemblance between the path thus deduced and that of ,comet ,i1 #ahje4 ,gradually the idea dawned upon him that a new era was opening for science4 ,hitherto the only periodical comets which had been discovered except ,lexell's--the #8lost comet'--had travelled in orbits extending far out into space beyond the paths of the most distant known planets4 ,but now ,encke saw reason to believe that he had to deal with a comet travelling within the orbit of ,jupiter4 ,on ,february #e1 he wrote to the eminent mathematician ,gauss1 pointing out the results of his inquiries1 and saying that he only waited for the encouragement and authority of his former teacher to prosecute his researches to the end towards which they already seemed to point4 ,gauss1 in reply1 not only encouraged ,encke to proceed1 but counselled him as to the course he should pursue4 ,the result we all know4 ,encke showed conclusively that the newly-discovered comet travels in a path of short period1 and that it had already made its appearance several times in our neighbourhood4 ,from the date of this discovery1 ,encke took high rank among the astronomers of ,europe4 ,his subsequent labours by no means fell short of the promise which this1 his first notable achievement1 had afforded4 ,if he effected less as an astronomical observer than many of his contemporaries1 he was surpassed by few as a manipulator of those abstruse formul by which the planetary perturbations are calculated4 ,it was to the confidence engendered by this skill that we owe his celebrated discovery of the acceleration of the motion of the comet mentioned above4 ,assured that he had rightly estimated the disturbances to which the comet is subjected1 he was able to pronounce confidently that some cause continually 7though all but imperceptibly7 impedes the passage of this body through space1 and so--by one of those strange relations which the student of astronomy is familiar with--the continually retarded comet travels ever more swiftly along a continually diminishing orbit4 ,bruhns' ,life of ,encke is well worth reading1 not only by those who are interested in ,encke's fame and work as an astronomer1 but by the general reader4 ,encke the man is presented to our view1 as well as ,encke the astronomer4 ,with loving pains the pupil of the great astronomer handles the theme he has selected4 ,the boyhood of ,encke1 his studies1 his soldier life in the great uprising against ,napoleon in #ahac1 and his work at the ,seeberge ,observatory2 his labours on comets and asteroids2 his investigations of the transits of #agfa and #agfi2 his life as an academician1 and as director of an important observatory2 his orations at festival and funeral2 and lastly1 his illness and death1 are described in these pages by one who held ,encke in grateful remembrance as #8teacher and master1' and as a #8fatherly friend4' ,not the least interesting feature of the work is the correspondence introduced into its pages4 ,we find ,encke in communication with ,humboldt1 with ,bessel and ,struve1 with ,hansen1 ,olbers1 and ,argelander2 with a host1 in fine1 of living as well as of departed men of science4 7,from ,nature1 ,march #aj1 #ahgj47 ,,footnotes3 #a ,other green lines have since been discovered in the auroral spectrum2 and occasionally a red line is seen4 #b ,in the ,quarterly ,journal of ,science for ,october #ahff1 a more detailed but somewhat less popular account of the subject of the above paper is presented4 ,a few months earlier1 a skilfully-written paper on the same subject1 from the pen of ,mr4 ,j4 ,m4 ,wilson1 of ,rugby1 had appeared in the ,eagle1 a magazine written by and for members of ,st4 ,john's ,college1 ,cambridge4 ,although my paper in the ,quarterly ,journal of ,science was written quite independently of ,mr4 ,wilson's 7which1 however1 ,i had read71 yet it chanced that in describing the same mathematical relations1 and the same sequence of events1 ,i here and there used language closely resembling his4 ,i fear this led for a while to some misconception2 but ,i was fortunately able to show in ,mr4 ,de la ,rue's address to the ,astronomical ,society1 on the same subject1 passages yet more strikingly resembling some in ,mr4 ,wilson's paper 7written subsequently and quite independently74 ,the fact would seem to be that if two persons describe exactly the same events1 and deal with exactly the same mathematical relations1 it is almost certain that in more than one passage they will use somewhat similar expressions4 ,i was actually indebted to ,mr4 ,wilson's paper for one illustration1 however1--that derived from the movements of a supposed artificial moon2 and ,i think that had his paper appeared in a magazine printed for general circulation1 ,i should have referred to it4 ,as it was1 this seemed useless so far as the readers of the ,quarterly ,journal of ,science were concerned4 ,the circumstances of the case were1 indeed1 far from calling for a reference2 while ,i had in a sense made the illustration my own by detecting an important miscalculation in the original 7the amount of advance being either doubled or halved--,i forget which74 ,had ,i referred to ,mr4 ,wilson's paper1 ,i must needs have mentioned this mistake2 and it would have appeared as though ,i had had no other purpose in making the reference4 ,i mention these matters to explain what ,i fear my esteemed fellow-collegian was disposed at the time to regard as either a wrong or a slight4 ,nothing was further from my intention than either4 ,,venus ,,on ,,the ,,sun',s ,,face4 ,more than a century ago scientific men were looking forward with eager interest to the passage of the planet ,venus across the sun's face in #agfi4 ,the ,royal ,society judged the approaching event to be of such extreme importance to the science of astronomy that they presented a memorial to ,king ,george ,,iii41 requesting that a vessel might be fitted out1 at ,government expense1 to convey skilful observers to one of the stations which had been judged suitable for observing the phenomenon4 ,the petition was complied with1 and after some difficulty as to the choice of a leader1 the good ship #8,endeavour1' of #cgj tons1 was placed under the command of ,captain ,cook4 ,the astronomical work entrusted to the expedition was completely successful2 and thus it was held that ,england had satisfactorily discharged her part of the work of utilising the rare phenomenon known as a transit of ,venus4 ,a century passed1 and science was again awaiting with interest the approach of one of these transits4 ,but now her demands were enlarged4 ,it was not one ship that was asked for1 but the full cost and charge of several expeditions4 ,and this time1 also1 science had been more careful in taking time by the forelock4 ,the first hints of her requirements were heard some fourteen years ago1 when the ,astronomer-,royal began that process of laborious inquiry which a question of this sort necessarily demands4 ,gradually1 her hints became more and more plain-spoken2 insomuch that ,airy--her mouthpiece in this case--stated definitely in #ahfh what he thought science had a right to claim from ,england in this matter4 ,when the claim came before our ,government1 it was met with a liberality which was a pleasing surprise after some former placid references of scientific people to their own devices4 ,the sum of ten thousand five hundred pounds was granted to meet the cost of several important and well-appointed expeditions2 and further material aid was derived from the various ,government observatories4 ,and now let us inquire why so much interest is attached to a phenomenon which appears1 at first sight1 to be so insignificant4 ,transits1 eclipses1 and other phenomena of that nature are continually occurring1 without any particular interest being attached to them4 ,the telescopist may see half-a-dozen such phenomena in the course of a night or two1 by simply watching the satellites of ,jupiter1 or the passage of our moon over the stars4 ,even the great eclipse of #ahfh did not attract so much interest as the transit of ,venus2 yet that eclipse had not been equalled in importance by any which has occurred in historic times1 and hundreds of years must pass before such another happens1 whereas transits of ,venus are far from being so uncommon4 ,the fact is1 that ,venus gives us the best means we have of mastering a problem which is one of the most important within the whole range of the science of astronomy4 ,i use the term important1 of course1 with reference to the scientific significance and interest of the problem4 ,practically1 it matters little to us whether the sun is a million of miles or a thousand millions of miles from us4 ,the subject must in any case be looked upon as an extra-parochial one4 ,but science does occasionally attach immense interest to extra-parochial subjects4 ,and this is neither unwise nor unreasonable1 since we find implanted in our very nature--and not merely in the nature of scientific men--a quality which causes us to take interest in a variety of matters that do not in the least concern our personal interests4 ,nor is this quality1 rightly considered1 one of the least noble characteristics of the human race4 ,that the determination of the sun's distance is important1 in an astronomical sense1 will be seen at once when it is remembered that the ideas we form of the dimensions of the solar system are wholly dependent on our estimate of the sun's distance4 ,nor can we gauge the celestial depths with any feeling of assurance1 unless we know the true length of that which is our sole measuring-rod4 ,it is1 in fact1 our basis of measurement for the whole visible universe4 ,in some respects1 even if we knew the sun's distance exactly1 it would still be an unsatisfactory gauge for the stellar depths4 ,but that is the misfortune1 not the fault1 of the astronomer1 who must be content to use the measuring-rod which nature gives him4 ,all he can do is to find out as nearly as possible its true length4 ,when we come to consider how the astronomer is to determine this very element--the sun's distance--we find that he is hampered with a difficulty of precisely the same character4 ,the sun being an inaccessible object1 the astronomer can apply no other methods to determine its distance--directly--than those which a surveyor would use in determining the distance of an inaccessible castle1 or rock1 or tree1 or the like4 ,we shall see presently that the ingenuity of astronomers has1 in fact1 suggested some other indirect methods4 ,but clearly the most satisfactory estimate we can have of the sun's distance is one founded on such simple notions and involving in the main such processes of calculation as we have to deal with in ordinary surveying4 ,there is1 in this respect1 no mystery about the solution of the famous problem4 ,unfortunately1 there is enormous difficulty4 ,when a surveyor has to determine the distance of an inaccessible object1 he proceeds in the following manner4 ,he first very carefully measures a base-line of convenient length4 ,then from either end of the base-line he takes the bearing of the inaccessible object--that is1 he observes the direction in which it lies4 ,it is clear that1 if he were now to draw a figure on paper1 laying down the base-line to some convenient scale1 and drawing lines from its ends in directions corresponding to the bearings of the observed object1 these lines would indicate1 by their intersection1 the true relative position of the object4 ,in practice1 the mathematician does not trust to so rough a method as construction1 but applies processes of calculation4 ,now1 it is clear that in this plan everything depends on the base-line4 ,it must not be too short in comparison with the distance of the inaccessible object2 for then1 if we make the least error in observing the bearings of the object1 we get an important error in the resulting determination of the distances4 ,the reader can easily convince himself of this by drawing an illustrative case or two on paper4 ,the astronomer has to take his base-line for determining the sun's distance1 upon our earth1 which is quite a tiny speck in comparison with the vast distance which separates us from the sun4 ,it had been found difficult enough to determine the moon's distance with such a short base-line to work from4 ,but the moon is only about a quarter of a million of miles from us1 while the sun is more than ninety millions of miles off4 ,thus the problem was made several hundred times more difficult--or1 to speak more correctly1 it was rendered simply insoluble unless the astronomer could devise some mode of observing which should vastly enhance the power of his instruments4 ,for let us consider an illustrative case4 ,suppose there was a steeple five miles off1 and we had a base-line only two feet long4 ,that would correspond as nearly as possible to the case the astronomer has to deal with4 ,now1 what change of direction could be observed in the steeple by merely shifting the eye along a line of two feet8 ,there is a ready way of answering4 ,invert the matter4 ,consider what a line of two feet long would look like if viewed from a distance of five miles4 ,would its length be appreciable1 to say nothing of its being measurable8 ,yet it is just such a problem as the measurement of that line which the astronomer would have to solve4 ,but even this is not all4 ,in our illustration only one observer is concerned1 and he would be able to use one set of instruments4 ,suppose1 however1 that from one end of the two-feet line an observer using one set of instruments took the bearings of the steeple2 and that1 half a year after1 another observer brought another set of instruments and took the bearing of the steeple from the other end of the two-feet line1 is it not obvious how enormously the uncertainty of the result would be increased by such an arrangement as this8 ,one observer would have his own peculiar powers of observation1 his own peculiar weaknesses3 the other would have different peculiarities4 ,one set of instruments would be characterised by its own faults or merits1 so would the other4 ,one series of observations would be made in summer1 with all the disturbing effects due to heat2 the other would be made in winter1 with all the disturbing effects due to cold4 ,the observation of the sun is characterised by all these difficulties4 ,limited to the base-lines he can measure on earth1 the astronomer must set one observer in one hemisphere1 another in the other4 ,each observer must have his own set of instruments2 and every observation which one has made in summer will have to be compared with an observation which the other has made in winter4 ,thus we can understand that astronomers should have failed totally when they attempted to determine the sun's distance without aid from the other celestial bodies4 ,it may seem at first sight as though nothing the other celestial bodies could tell the astronomer would be of the least use to him1 since these bodies are for the most part farther off than the sun1 and even those which1 approach nearest to us are still far beyond the limits of distance within which the simple plan followed by surveyors could be of any service4 ,and besides1 it might be supposed that information about the distance of one celestial body could be of no particular service towards the determination of the distance of another4 ,but two things aid the astronomer at this point4 ,first of all1 he has discovered the law which associates together the distances of all the planets from the sun2 so that if he can determine the distance of any one planet1 he learns immediately the distances of all4 ,secondly1 the planets in their motion travel occasionally into such positions that they become mighty indices1 tracing out on a natural dial-plate the significant lesson from which the astronomer hopes to learn so much4 ,to take an instance from the motions of another planet than the one we are dealing with4 ,mars comes sometimes so near the earth that the distance separating us from him is little more than one-third of that which separates us from the sun4 ,suppose that1 at such a time1 he is seen quite close to a fixed star4 ,that star gives the astronomer powerful aid in determining the planet's distance4 ,for1 to observers in some parts of the earth1 the planet will seem nearer to the star than he will to observers elsewhere4 ,a careful comparison of the effects thus exhibited will give significant evidence respecting the distance of ,mars4 ,and we see that the star has served as a fixed mark upon the vast natural dial of the heavens1 just as the division-marks on a clock-face serve to indicate the position of the hands4 ,now we can at once see why ,venus holds so important a position in this sort of inquiry4 ,venus is our nearest neighbour among the planets4 ,she comes several millions of miles nearer to us than ,mars1 our next neighbour on the other side4 ,that is the primary reason of her being so much considered by astronomers4 ,but there is another of equal importance4 ,venus travels nearer than our earth to the sun4 ,and thus there are occasions when she gets directly between the earth and the sun4 ,at those times she is seen upon his face1 and his face serves as a dial-plate by which to measure her movements4 ,when an observer at one part of the earth sees her on one part of the sun's face1 another observer at some other part of the earth will see her on another1 and the difference of position1 if accurately measured1 would at once indicate the sun's distance4 ,as a matter of fact1 other modes of reading off the indications of the great dial-plate have to be adopted4 ,before proceeding to consider those modes1 however1 we must deal with one or two facts about ,venus's movements which largely affect the question at issue4 ,let us first see what we gain by considering the distance of ,venus rather than that of the sun4 ,at the time of a transit ,venus is of course on a line between the earth and the sun1 and she is at somewhat less than a third of the sun's distance from us4 ,thus whatever effect an observer's change of place would produce upon the sun would be more than trebled in the case of ,venus4 ,but it must not be forgotten that we are to judge the motions of ,venus by means of the dial-plate formed by the solar disc1 and that dial-plate is itself shifted as the observer shifts his place4 ,venus is shifted three times as much1 it is true2 but it is only the balance of change that our astronomer can recognise4 ,that balance is1 of course1 rather more than twice as great as the sun's change of place4 ,so far1 then1 we have not gained much1 since it has been already mentioned that the sun's change of place is not measurable by any process of observation astronomers can apply4 ,it is to the fact that we have the sun's disc1 whereby to measure the change1 that we chiefly trust2 and even that would be insufficient were it not for the fact that ,venus is not at rest1 but travels athwart the great solar dial-plate4 ,we are thus enabled to make a time measurement take the place of a measurement of space4 ,if an observer in one place sees ,venus cross the sun's face at a certain distance from the centre1 while an observer at another place sees her follow a path slightly farther from the centre1 the transit clearly seems longer to the former observer than to the latter4 ,this artifice of exchanging a measurement of time for one of space--or vice vers--is a very common one among astronomers4 ,it was ,edmund ,halley1 the friend and pupil of ,sir ,isaac ,newton1 who suggested its application in the way above described4 ,it will be noticed that what is required for the successful application of the method is that one set of observers should be as far to the north as possible1 another as far to the south1 so that the path of ,venus may be shifted as much as possible4 ,clearly the northern observers will see her path shifted as much to the south as it can possibly be1 while the southern observers will see the path shifted as far as possible towards the north4 ,one thing1 however1 is to be remembered4 ,a transit lasts several hours1 and our observers must be so placed that the sun will not set during these hours4 ,this consideration sometimes involves a difficulty4 ,for our earth does not supply observing room all over her surface1 and the region where observation would be most serviceable may be covered by a widely-extended ocean4 ,then again1 the observing parties are being rapidly swayed round by the rotating earth and it is often difficult to fix on a spot which may not1 through this cause1 be shifted from a favourable position at the beginning of the transit to an unfavourable one at the end4 ,without entering on all the points of difficulty involved by such considerations as these1 ,i may simply indicate the fact that the astronomer has a problem of considerable complexity to solve in applying ,halley's method of observation to a transit of ,venus4 ,it was long since pointed out by the ,french astronomer ,delisle that the subject may be attacked another way--that1 in fact1 instead of noticing how much longer the transit lasts in some places than in others1 the astronomer may inquire how much earlier it begins or ends in some places than in others4 ,here is another artifice1 extremely simple in principle1 though not altogether so simple in its application4 ,my readers must bear with me while ,i briefly describe the qualities of this second method1 because in reality the whole question of the transit1 and all the points which have to be attended to in the equipment and placing of the various observing parties1 depend on these preliminary matters4 ,without attending to them--or at least to such primary points as ,i shall select--it would be impossible to form a clear conception of the circumstances with which astronomers have to deal4 ,there is1 however1 no real difficulty about this part of the subject1 and ,i shall only ask of the reader to give his attention to it for a very brief space of time4 ,suppose the whole of that hemisphere of the earth on which the sun is shining when the transit is about to begin were covered with observers waiting for the event4 ,as ,venus sweeps rapidly onwards to the critical part of her path1 it is clear that some of these observers will get an earlier view of the commencement of the transit than others will2 just as at a boat-race1 persons variously placed round a projecting corner of the course see the leading boat come into view at different times4 ,some one observer on the outer rim of the hemisphere would be absolutely the first to see the transit begin4 ,then rapidly other observers would see the phenomenon2 and in the course of a few minutes some one observer on the outer rim of the hemisphere--almost exactly opposite the first--would be absolutely the last to see the transit begin4 ,from that time the transit would be seen by all for several hours--,i neglect the earth's rotation1 for the moment--but the end of the transit1 like the beginning1 would not be seen simultaneously by the observers4 ,first one would see it1 then in succession the rest1 and last of all an observer almost exactly opposite the first4 ,now1 here we have had to consider four observers who occupy exceptional positions4 ,there is 7#a7 the observer who sees the transit begin earliest1 7#b7 the one who sees it begin latest1 7#c7 the one who sees it end earliest1 and 7#d7 the one who sees it end latest4 ,let us consider the first two only4 ,suppose these two observers afterwards compared notes1 and found out what was the exact difference of time between their respective observations4 ,is it not clear that the result would at once afford the means of determining the sun's distance8 ,it would be the simplest of all possible astronomical problems to determine over what proportion of her orbit ,venus passed in the interval of time which elapsed between these observations2 and the observers would now have learned that that portion of ,venus's orbit is so many miles long1 for they know what distance separated them1 and it would be easy to calculate how much less that portion of ,venus's orbit is4 ,thus they would learn what the length of her whole orbit is1 thence her distance from the sun1 and thence the sun's distance from us4 ,the two observers who saw the transit end earliest and latest could do the like4 ,speaking generally1 and neglecting all the complexities which delight the soul of the astronomer1 this is ,delisle's method of utilising a transit4 ,it has obviously one serious disadvantage as compared with the other4 ,an observer at one side of the earth has to bring his observations into comparison with those made by an observer at the other side of the earth4 ,each uses the local time of the place at which he observes1 and it has been calculated that for the result to be of value there must not be an error of a single second in their estimates of local time4 ,now1 does the reader appreciate the full force of this proviso8 ,each observer must know so certainly in what exact longitude he is1 that his estimate of the time when true noon occurs shall not be one second wrong6 ,this is all satisfactory enough in places where there are regular observatories4 ,but matters are changed when we are dealing with such places as ,woahoo1 ,kerguelen ,land1 ,chatham ,island1 and the wilds of ,siberia4 ,in the transit#c of #ahgd there are many such difficulties to be encountered4 ,in fact1 it is almost impossible to conceive a transit the circumstances of which are more inconvenient4 ,on the other hand1 however1 the transit is of such a nature that if once the preliminary difficulties are overcome1 we can hope more from its indications than from those of any other transit which will happen in the course of the next few centuries4 ,the transit will begin earliest for observers in the neighbourhood of the ,sandwich ,islands1 latest for observers near ,crozet ,island1 far to the south-east of the ,cape of ,good ,hope4 ,it ends earliest for observers far to the south-west of ,cape ,horn1 latest for observers in the north-eastern part of ,european ,russia4 ,thus we see that1 so far as the application of our second method is concerned1 the suitable spots are not situated in the most inviting regions of the earth's surface4 ,as the transit happens on ,december #h1 #ahgd1 the principal northern stations will be very bleak abodes for the observers4 ,the southern stations are in yet more dreary regions1--notwithstanding the fact that the transit occurs during the summer of the southern hemisphere4 ,for the application of ,halley's method we require stations where the whole transit will be visible2 and as the days are very short at the northern stations in ,december1 it is as respects these that we encounter most difficulty4 ,however1 it has been found that many places in ,northern ,china1 ,japan1 ,eastern ,siberia1 and ,manchouria are suitable for the purpose4 ,the best southern stations for this method lie unfortunately on the unexplored ,antarctic continent and the islands adjacent to it2 but ,crozet ,island1 ,kerguelen ,land1 and some other places more easy of access than the ,antarctic continent1 will serve very well4 ,indeed1 ,england has so many stations to occupy elsewhere that it is doubtful whether she will care to undertake the dangerous and difficult task of exploring the ,antarctic wastes to secure the best southern stations4 ,the work may fairly be left to other nations1 and doubtless will be efficiently carried out4 ,what ,england will actually undertake has not yet been fully decided upon4 ,we may be quite certain that she will send out a party to ,woahoo or ,hawaii to observe the accelerated commencement of the transit4 ,she will also send observers to watch the retarded commencement1 but whether to ,crozet ,island1 ,kerguelen ,land1 ,mauritius1 or ,rodriguez is uncertain4 ,possibly two parties will be sent out for this purpose1 and most likely ,rodriguez and ,mauritius will be the places selected4 ,it had been thought until lately that the sun would be too low at some of the places when the transit begins1 but a more exact calculation of the circumstances of the transit has shown this to be a mistake4 ,both ,crozet ,island and ,kerguelen ,land are very likely to be enveloped in heavy mists when the transit begins--that is1 soon after sunrise--hence the choice of ,mauritius and ,rodriguez as the most suitable station4 ,england will also be called on to take an important part in observing the accelerated end of the transit4 ,a party will probably be sent to ,chatham ,island or ,campbell ,island1 not far from ,new ,zealand4 ,it had been thought that at the former island the sun would be too low2 but here1 again1 a more exact consideration of the circumstances of the transit has led astronomers to the conclusion that the sun will be quite high enough at this station4 ,the ,russian observers are principally concerned with the observation of the retarded end of the transit1 nearly all the best stations lying in ,siberia4 ,but there are several stations in ,british ,india where this phase can be very usefully observed2 and doubtless the skilful astronomers and mathematicians who are taking part in the survey of ,india will be invited--as at the time of the great eclipse--to give their services in the cause of science4 ,alexandria1 also1 though inferior to several of the ,indian stations1 will probably be visited by an observing party from ,england4 ,it will be seen that ,england will thus be called on to supply about half-a-dozen expeditions to view the transit4 ,all of these will be sent out in pursuance of ,delisle's mode of utilising a transit1 so that1 for reasons already referred to1 it will be necessary that they should be provided with instruments of the utmost delicacy1 and very carefully constructed4#d ,they will have to remain at their several stations for a long time before the transit takes place--several months1 at least--so that they may accurately determine the latitude of the temporary observatories they will erect4 ,this is a work requiring skilled observers and recondite processes of calculation4 ,hence it is that the cost of sending out these observing parties is so considerable4 ,the only ,english party which will apply ,halley's method of observation is the one which will be stationed at ,mauritius1 under ,lord ,lindsay4 ,this part of their work will be comparatively easy1 the method only requiring that the duration of the transit should be carefully timed4 ,in fact1 one of the great advantages of ,halley's method is the smallness of the expense it involves4 ,a party might land the day before the transit1 and sail away the day after1 with results at least as trustworthy as those which a party applying ,delisle's method could obtain after several months of hard work4 ,it is to this1 rather than any other cause1 that the small expense of the observations made in #agfi is to be referred4 ,and doubtless had it been decided by our astronomical authorities to apply ,halley's method solely or principally1 the expense of the transit-observations would have been materially lessened4 ,there would1 however1 have been a risk of failure through the occurrence of bad weather at the critical stations2 whereas now--as other nations will doubtless avail themselves of ,halley's method--the chance that the transit-observations will fail through meteorological causes is very largely diminished4 ,science will owe much to the generosity of ,england in this respect4 ,it is1 indeed1 only recently that the possibility of applying ,halley's method has been recognised4 ,it had been thought that the method must fail totally in #ahgd4 ,but on a more careful examination of the circumstances of the transit1 a ,french astronomer1 ,m4 ,puiseux1 was enabled to announce that this is not the case4 ,almost simultaneously ,i published calculations pointing to a similar result2 but having carried the processes a few steps further than ,m4 ,puiseux1 ,i was able to show that ,halley's method is not only available in #ahgd1 but is the more powerful method of the two4 ,unfortunately1 there is an element of doubt in the inquiry1 of which no amount of care on the part of our observers and mathematicians will enable them to get rid4 ,i refer to the behaviour of ,venus herself4 ,it is to the peculiarity we are now to consider that the quasi-failure of the observations made in #agfi must be attributed4 ,it is true that ,mr4 ,stone1 the first-assistant at the ,greenwich ,observatory1 has managed to remove the greater part of the doubts which clouded the results of those observations4 ,but not even his skill and patience can serve to remove the blot which a century of doubt has seemed to throw upon the most exact of the sciences4 ,we shall now show how much of the blame of that unfortunate century of doubt is to be ascribed to ,venus4 ,at a transit1 astronomers confine their attention to one particular phase--the moment1 namely1 when ,venus just seems to lie wholly within the outline of the sun's disc4 ,this at least was what ,halley and ,delisle both suggested as desirable4 ,unfortunately1 ,venus had not been consulted1 and when the time of the transit came she declined to enter upon or leave the sun's face in the manner suggested by the astronomers4 ,consider1 for example1 her conduct when entering on the sun's face3-- ,at first1 as the black disc of the planet gradually notched the edge of the sun's disc1 all seemed going on well4 ,but when somewhat more than half of the planet was on the sun's face1 it began to be noticed that ,venus was losing her rotundity of figure4 ,she became gradually more and more pear-shaped1 until at last she looked very much like a peg-top touching with its point the edge of the sun's disc4 ,then suddenly--#8as by a lightning flash1' said one observer--the top lost its peg1 and then gradually ,venus recovered her figure1 and the transit proceeded without further change on her part until the time came for her to leave the sun's face1 when similar peculiarities took place in a reversed order4 ,here was a serious difficulty indeed4 ,for when was the moment of true contact8 ,was it when the peg-top figure seemed just to touch the edge of the sun8 ,this seemed unlikely1 because a moment after the planet was seen well removed from the sun's edge4 ,was it when the rotund part of the planet belonged to a figure which would have touched the sun's edge if the rotundity had been perfect elsewhere8 ,this1 again1 seemed unlikely1 because at this moment the black band connecting ,venus and the sun was quite wide4 ,and1 besides1 if this were the true moment of contact1 what eye could be trusted to determine the occurrence of a relation so peculiar8 ,yet the interval between this phase and the final or peg-top phase lasted several seconds--as many as twenty-two in one instance in #agfi--;and the whole success of the observation depended on exactness within three or four seconds at the outside4 ,we know that ,venus will act in precisely the same manner in #ahgd4 ,if we had been induced to hope that improvements in our telescopes would diminish the peculiarity1 the observations of the transit of ,mercury1 in ,november #ahfh1 would have sufficed to destroy that hope1 for even with the all but perfect instruments of the ,greenwich ,observatory1 ,mercury assumed the peg-top disguise in the most unpleasing manner4 ,it may be asked1 then1 ,what do astronomers propose to do in #ahgd to prevent ,venus from misleading them again as she did in #agfi8 ,much has already been done towards this end4 ,mr4 ,stone undertook a series of careful researches to determine the law according to which ,venus may be expected to behave1 or to misbehave herself2 and the result is1 that he has been able to tell the observers exactly what they will have to look for1 and exactly what it is most important that they should record4 ,in #agfi1 observers recorded their observations in such doubtful terms1 owing to their ignorance of the real significance of the peculiarities they witnessed1 that the mathematicians who had to make use of those observations were misled4 ,hinc ill lacrym4 ,hence it is that an undeserved reproach has fallen upon the #8exact science4' ,the amount of the error resulting from the misinterpretation of the observations made in #agfi was1 however1 very small indeed1 when its true character is considered4 ,it is1 indeed1 easy to make the error seem enormous4 ,the sun's distance came out some four millions of miles too large1 and that seems no trifling error4 ,then1 again1 the resulting estimate of the distance of ,neptune came out more than a hundred million miles too great2 while even this enormous error was as nothing when compared with that which resulted when the distances of the fixed stars were considered4 ,but this is an altogether erroneous mode of estimating the effect of the error4 ,it would be as absurd to count up the number of hairs' breadth by which the geographer's estimates of the length and breadth of ,england may be in error4 ,in all such matters it is relative and not absolute error we have to consider4 ,a microscopist would have made a bad mistake who should over-estimate the length of a fly's proboscis by a single hair's breadth2 but the astronomer had made a wonderfully successful measurement of the sun's distance who deduced it within three or four millions of miles of the true value4 ,for it is readily calculable that the error in the estimated relative bearing of the sun as seen from opposite sides of the earth corresponds to the angle which a hair's breadth subtends when seen from a distance of #abe feet4 ,the error was first detected when other modes of determining the sun's distance were applied by the skilful astronomers and physicists of our own day4 ,we have no space to describe as fully as they deserve the ingenious processes by which the great problem has been attacked without aid from ,venus4 ,indeed1 we can but barely mention the principles on which those methods depend4 ,but to the reader who takes interest in astronomy1 we can recommend no subject as better worth studying than the masterly researches of ,foucault1 ,leverrier1 and ,hansen upon the problem of the sun's distance4 ,the problem has been attacked in four several ways4 ,first1 the tremendous velocity of light has been measured by an ingenious arrangement of revolving mirrors2 the result combined with the known time occupied by light in travelling across the earth's orbit immediately gives the sun's distance4 ,secondly1 a certain irregularity in the moon's motion1 due to the fact that she is most disturbed by the sun when traversing that half of her path which is nearest to him1 was pressed into the service with similar results4 ,thirdly1 an irregularity in the earth's motion1 due to the fact that she circles around the common centre of gravity of her own mass and the moon's1 was made a means of attacking the problem4 ,lastly1 ,mars1 a planet which1 as we have already mentioned1 approaches us almost as nearly as ,venus1 was found an efficient ally4 ,the result of calculations founded on these methods showed that the sun's distance1 instead of being about #ie1jjj1jjj miles1 is little more than #ia1ejj1jjj miles4 ,and recently a re-examination of the observations made upon ,venus in #agfi led ,mr4 ,stone to believe that they point to a similar result4 ,doubtless1 however1 we must wait for the transit of ,venus in #ahgd before forming a final decision as to the estimate of the sun's distance which is to take its place in popular works on astronomy during the next century or so4 ,nothing but an unlooked-for combination of unfavourable circumstances can cause the failure of our hopes4 ,certainly1 if we should fail in obtaining satisfactory results in #ahgd1 the world will not say that the generosity of the ,english ,government has been in fault1 since it would be difficult to find a parallel in the history of modern science to the munificence of the grant which has been made this year for expeditions to observe a phenomenon whose interest and importance are purely scientific4 7,from ,st4 ,paul's1 ,october #ahfi47 ,,footnotes3 #c ,the reader will remember the time at which the essay appeared4 ,for several reasons it seems well to leave the essay unaltered4 ,in the second series of ,light ,science a later stage is presented1 and the account is carried up to the present date in my work on ,the ,transits of ,venus4 #d ,it is held to be of the utmost importance that all the observing parties should use similar telescopes4 ,,britain',s ,,coal ,,cellars4 ,it would have been deemed a strange thought in the days of the ,tudors to suggest that ,england's greatness would one day depend1--or seem to depend1--on her stores of coal1 a mineral then regarded as only an unpleasant rival of the wood-log for household fires4 ,when ,shakespeare put into the mouth of ,faulconbridge the words-- ,this ,england never did1 nor never shall1 ,lie at the proud foot of a conqueror1 ,but when it first did help to wound itself1 he would have thought it a singular proviso that ,england should be watchful of her coal stores if she would preserve her position among the nations4 ,and yet there is a closer connection between the present greatness of ,britain and the mighty coal cellars underlying certain ,british counties than we are commonly prepared to acknowledge4 ,saxon steadiness and ,norman energy have doubtless played their part in placing ,britain in the position she now holds2 but whatever may have been the case in past ages of our history1 it is certain that at present there is much truth in ,liebig's assertion that ,england's power is in her coal4 ,the time may come again1 as the time has been1 when we shall be less dependent on our coal stores1--when bituminous bankruptcy will not be equivalent to national bankruptcy2 but if all our coal mines were at this moment rendered unworkable1 the power of ,england would receive a shock from which it would be ages in recovering4 ,i have quoted an assertion made many years since by ,baron ,liebig4 ,the assertion was accompanied by another not less striking4 #8,civilisation1' he said1 #8is the economy of power2 and ,english power is coal4' ,it is on this text that ,i propose now to comment4 ,there has recently been issued a ,blue ,book1 bearing in the most important manner on the subject of ,england's coal-supply4 ,for five years fifteen eminent ,commissioners have been engaged in examining the available evidence respecting the stores of coal contained in the various coal-fields of ,great ,britain4 ,their inquiries were commenced soon after the time when the fears of the country on this subject were first seriously awakened2 and were directed specially to ascertain how far those fears were justified by the real circumstances of the case4 ,it will be well to compare the various opinions which were expressed before the inquiries were commenced1 with the results which have now been obtained4 ,in the first place it should be noticed that the subject had attracted the attention of men of science many years ago4 ,some forty years#e have passed since ,dr4 ,buckland1 in one of the ,bridgewater ,treatises1 pointed to the necessity for a careful examination of our coal stores1 lest ,england should drift unawares into what he called #8bituminous bankruptcy4' ,at that time the quantity of coal raised annually in ,england amounted to but about forty millions of tons4 ,ten years later the annual yield had risen to about fifty millions of tons2 and then another warning voice was raised by ,dr4 ,arnold4 ,ten more years passed1 and the annual yield had increased to #hc1fce1bad tons1 when ,mr4 ,hull made the startling announcement that our coal stores would last us but about two centuries1 unless some means were adopted to check the lavish expenditure of our black diamonds4 ,but it was undoubtedly the address of ,sir ,w4 ,armstrong to the ,british ,association1 in #ahfc1 which first roused the attention of the country to the importance of the subject4 #8,the greatness of ,england1' he said1 #8depends much upon the superiority of her coal1 in cheapness and quality1 over that of other nations4 ,but we have already drawn from our choicest mines a far larger quantity of coal than has been raised in all other parts of the world put together2 and the time is not remote when we shall have to encounter the disadvantages of increased cost of working and diminished value of produce4' ,then he summed up the state of the case as he viewed it4 #8,the entire quantity of available coal existing in these islands has been calculated to amount to #hj1jjj millions of tons1 which1 at the present rate of consumption1 would be exhausted in #icj years2 but with a continued yearly increase of #b millions of tons would only last #bab years4' ,other statements were not wanting1 however1 which presented matters in a more favourable light4 ,mr4 ,hussey ,vivian1 ,m4,p41 expressed the opinion that ,south ,wales alone could supply all ,england with coals for #ejj years4 ,mr4 ,r4 ,c4 ,taylor1 of the ,geological ,society1 said that our coal stores would suffice for #a1gjj years4 ,and there were some who adopted a yet more sanguine view of our position4 ,on the other hand1 ,mr4 ,edward ,hull1 of the ,geological ,survey1 calculated that with an increase of but one million and a half of tons per annum--considerably less than even the average increase for the preceding decade#f--our coals would last us but a little more than #cjj years4 ,mr4 ,stanley ,jevons1 in his masterly treatise on #8,the ,coal ,question1' adopted a mode of considering the increase1 which has led to an even more unpleasant conclusion than any hitherto obtained4 ,he observed that the quantity of coal raised in successive years is not merely increasing1 but the amount of increase is itself increasing4 #8,we1 of course1 regard not1' he said1 #8the average annual arithmetical increase of coal consumption between #ahed and #ahfc1 which is #b1djc1dbd tons1 but the average rate per cent4 of increase1 which is found by computation to be #cbf per cent4' ,that is to say1 for every hundred tons of coal consumed in one year1 #ajc tons1 or thereabouts1 would be consumed in the next--taking one year with another4 ,without entering into technicalities1 or niceties of calculation1 it is easy to show the difference between this view of the matter and a view founded only on the average increase during so many years4 ,consider #aj1jjj tons of coal sold in one year1 then ,mr4 ,stanley ,jevons points out that instead of that amount1 #aj1cbf would be sold in the next2 and so far we may suppose that the other view would agree with his4 ,but in the next1 or third year 7always remembering1 however1 that we must take one year with another71 the increase of #cbf tons would not be merely doubled1 according to ,mr4 ,stanley ,jevons2 that is1 the consumption would not be only #aj1feb tons3--the #aj1jjj of the second year would be replaced by #aj1cbf tons in the third year1 and the remaining #cbf would be increased by #c tons for each hundred1 or by rather more than #aj tons2 so that in all there would be #aj1ffb tons1 instead of #aj1feb4 ,now the difference in this third year seems small1 though when it is applied to about nine thousand times #aj1jjj tons it is by no means small1 amounting in fact to #ie1jjj tons2 but when the principle is extended to sequent years its effects assume paramount importance4 ,the small increase is as the small increase of a farthing for the second horseshoe-nail in the well-known problem4 ,the effects1 after a few years have passed1 correspond to the thousands of pounds by which the last shoe-nails of that problem increase the cost of the horse4 ,as ,mr4 ,leonard ,lemoran points out in the paper mentioned in the above note1 if the assumed rate per cent4 of increase continue1 #8we should draw in the year #aijj from our rocks more than #cjj millions of tons1 and in #aiej more than #b1jjj millions4#g ,about #cjj1jjj miners are now 7#ahff7 employed in raising rather more than #ib millions of tons of coals2 therefore more than eight million miners would be necessary to raise the quantity estimated as the produce of #aiej4 ,one-third of the present population of ,great ,britain would be coal miners4' ,or as ,mr4 ,jevons himself sums up our future1 #8,if our consumption of coal continue to multiply for #aaj years at the same rate as hitherto1 the total amount of coal consumed in the interval would be #ajj1jjj millions of tons4' ,now as ,mr4 ,hull estimated the available coal in ,great ,britain1 within a depth of #d1jjj feet1 at #hc1jjj millions of tons1 it followed that1 adopting ,mr4 ,jevons's mode of calculation1 a century would exhaust #8all the coal in our present workings1 as well as all the coal seams which may be found at a depth of #a1ejj feet below the deepest working in the kingdom4' ,it should be added1 however1 that ,mr4 ,stanley ,jevons mentioned #bjj1jjj millions of tons as the probable limit of the coal supplies of ,great ,britain4 ,the opinion of ,mr4 ,jevons respecting the probable rate of increase of our consumption was not accepted by the generality of those who examined the subject in #ahfe and #ahff4 ,there were some1 indeed1 who considered that the assumption was #8absurd in every point of view4' ,in one sense1 indeed1 ,mr4 ,jevons himself would have been ready to admit that his estimates would not be justified by the result4 ,the observed rate of increase could not possibly be maintained beyond a certain epoch1 simply because there would not be enough men to work the coal mines to the extent required4 ,but1 regarding the increase as indicating the requirements of the kingdom1 it would matter little whether the necessary supply failed for want of coal or for want of the means of raising the coal4 ,in other words1 removing the question from the arena of geological dispute1 and considering only the requirements of the country1 we should have this disagreeable conclusion forced upon us1 if ,mr4 ,jevons's estimate is just1 that ,england will not be able1 a century1 or even half a century hence1 to get as many coals from her subterranean cellars as she will then require4 ,she may have the coals1 but she will not have men enough to bring them to bank4 ,it is1 perhaps1 in this aspect1 that the question assumes its chief interest for us4 ,rightly understood1 the statements of ,mr4 ,jevons were of vital importance2 so important1 indeed1 that the nation might have looked forward to the results of the ,commission much as a patient would await the physician's report of the result of a stethoscopic examination4 ,the power of the nation residing--for the nonce at least--in her coal1 the enforced consumption of coal at a rate which cannot be maintained 7from whatever cause71 means to all intents and purposes the decline and approaching demise of ,england's power as a nation4 ,furthermore1 apart from all inquiries such as the ,commissioners undertook to make1 the mere statement of the successive annual yields was to be looked upon as of vital interest1 precisely as the progressive waste of a consumptive patient's strength and substance suggests even more serious apprehensions than the opinion of the physician4 ,i have said that many eminent authorities held that the rate of increase assumed by ,mr4 ,jevons would not actually prevail4 ,but some went farther1 and questioned whether the average annual arithmetical increase of the lately passed years would continue even for the next few years after the publication of ,mr4 ,jevons's work4 #8,such a continued increase as that1 which has taken place during the last five years1' wrote an excellent practical authority1 #8cannot continue for the next ten years1'--far less1 therefore1 that increasing rate of increase which ,mr4 ,jevons had assumed4 ,the same writer went farther even than this4 ,for1 after pointing out that the exportation of coal would probably be soon reduced1 rather than undergo1 as during the past1 a steady increase1 he added that #8on every side there were evidences of the most decided character1 warranting the supposition that the annual exhaustion of our coal fields would not at any period much exceed the hundred million tons which it had nearly reached' 7in #ahff74 ,one of the most interesting questions1 then1 which the ,commissioners were called upon to decide was1 whether1 at least during the period of their labours1 the anticipations of ,mr4 ,jevons would be fulfilled or not4 ,it is easy to compare his anticipations with those above quoted2 or rather1 it is easy to determine whether ,mr4 ,jevons's theory of an increasing increase1 or the theory of a uniform average increase1 accords best with the experience of the last five years4 ,to make the comparison fairly we must adopt the figures on which his own estimate was founded4 ,we have seen that he rejected the annual increase of #b1djc1dbd deduced from the records of the nine preceding years1 and adopted instead an increase of #c per cent4 year by year1 taking one year with another4 ,his own calculations gave for this year #ahga a consumption of #aah millions of tons1--an enormous increase on the annual consumption when he wrote4 ,according to the view he rejected1 the consumption for the year #ahga is easily computed1 though slightly different results will be obtained1 according to the year we choose to count from4 ,the annual increase above mentioned gives an increase of #bd1jcd1bdj tons in ten years1 and if we add this amount to the consumption in #ahfa 7#hc1fce1bad tons7 we obtain for the year #ahga a consumption of #ajg1ffi1ded tons4 ,on the other hand1 if we add eight years' increase to the consumption of #ahfc 7#hh1bib1eae tons71 we obtain #ajg1eai1ijg tons4#h ,it will be seen that there is an important difference between the consumption for #ahga1 as estimated according to ,mr4 ,jevons's view1 and according to the average rate of increase in the nine preceding years4 ,as the matter stood in #ahfe1 the great question concerning the consumption of the year #ahga would have been1--whether it would be nearer #aah millions1 the estimate of ,mr4 ,jevons2 or to #ajg millions1 the estimate1 according to the annual rate of increase2 or1 lastly1 to a number of tons1 not much1 if at all1 exceeding #ajj millions8 ,the answer of the ,commissioners comes in no doubtful terms4 ,judging from the consumption during the four years ending in #ahgj1 the estimated consumption for the year #ahgb is no less than #aae millions1 an amount approaching ,mr4 ,jevons's estimate much more nearly than could be desired4 ,indeed1 if we consider the imperfect nature of the statistics on which he founded his calculations1 the agreement between his estimate and the observed result must be regarded as surprisingly close4 ,remembering the conclusion to which ,mr4 ,jevons came with respect to the period for which our coal stores would last1 and noticing the close agreement thus far between his anticipations and the result1 we can well understand the warning tone of the report issued by the ,commissioners4 #8,every hypothesis1' they say1 #8must be speculative1 but it is certain that if the present rate of increase in the consumption of coal be indefinitely continued1 even in an approximate degree1 the progress towards the exhaustion of our coal will be very rapid4' ,let it be remembered that the ,commission was issued at the instance of those who took the more sanguine view1 and that it included within its ranks such eminent authorities as ,sir ,william ,armstrong1 ,sir ,robert ,murchison1 ,professor ,ramsay1 ,mr4 ,john ,hunt1 and others of like experience in the subject under inquiry4 ,if1 in the next place1 we compare ,mr4 ,jevons's estimate of the quantity of coal available for use with the result obtained by the ,commissioners1 we find little to restore our confidence in the extent of time during which our coal stores may be expected to last4 ,we have seen that #bjj1jjj millions of tons had been supposed to be available2 but the ,commissioners find that #8we now have an aggregate of #adf1dhj millions of tons1 which may be reasonably expected to be available for use4' ,again1 it had been supposed that our coal mines could be worked to a depth of #d1jjj feet1 or to an even greater depth4 #8,the difficulties in the way of deep mining1' wrote ,mr4 ,lemoran in #ahff1 #8are mere questions of cost4 ,it is important to notice that the assumption of #d1jjj feet as the greatest depth to which coal can be worked1 on account of the increase of temperature1 is purely voluntary4 ,the increase has been calculated at a rate for which there is no authority2 and while we are saying our coal-beds cannot be worked below #d1jjj feet1 a colliery in ,belgium has nearly approached that depth1 and no inconvenience is experienced by the miners4' ,but the ,commissioners state that at a depth of only #b1dai feet in the ,rosebridge mine 7the deepest in ,england71 the temperature is #id degrees of ,fahrenheit1 or within four degrees of blood heat4 #8,the depth at which the temperature of the earth would amount to blood heat1' they add1 #8is about #c1jjj feet4' ,they express a belief that by the #8long wall system' of working 7a system as yet seldom adopted in the chief northern mines7 it will be possible to reach a depth of #c1dbj feet before this heat is attained2 but it is by no means certain that this will prove to be the case4 ,on the other hand1 it will be well to regard the more promising aspect of the question4 ,we must not forget1 in the first place1 that in all matters of statistical research there is room for misapprehension unless careful attention be paid1 not merely to the observed facts1 but to the circumstances with which those facts are more or less intimately associated4 ,if we consider1 for example1 the progress of the consumption of our coal during the past fifteen years1 we find that a law of increase exists1 which is1 as we have seen1 easily expressed1 and which1 after being tested by a process resembling prediction1 has been singularly confirmed by the result4 ,but if we inquire into the various causes of the great increase in the consumption of coals1 we find that while those causes have been increasing in activity--so to speak--to a degree quite sufficient to explain the observed consumption1 they are yet such as in their very nature must needs be unable to pass beyond a certain range of increase4 ,thus the population of ,great ,britain has been steadily increasing1 and at present the annual increase is itself increasing4 ,then the amount of coal used in inland communication is increasing1 not only on account of the gradual extension of the railway network1 but also on account of the increase of population1 of commerce1 and so on4 ,again1 our commerce with other countries has increased with great rapidity since the year #ahfj1 when the ,french treaty came into operation1 and it will continue to increase with the increase of our population1 of our means of communication within our own country as well as with foreign countries1 and so on4 ,but all these causes of increase are now growing in activity at a rate which must inevitably diminish4 ,our population cannot increase beyond a certain extent1 because the extent of the country will suffice for but a certain number of inhabitants4 ,if emigration do not prevent increase beyond that number1 other causes will1 or else a much more serious evil than the exhaustion of all our coal stores awaits the country4 ,again1 the requirements of inland communication will before long be so far met that no such rapid extension as is now in progress will be called for4 ,after convenient communication has been established between all parts of the country--whether the process require the formation of new lines or of new services--no important increase can be required4 ,as regards our commerce1 its increase depends necessarily on the increase at present going on in the requirements of the country4 ,year by year ,britain has a larger population1 and the average requirements of each member of the population are also increasing4 ,but we have seen that the increase of her population is necessarily limited2 and although the increase of the requirements of her people may not be 7strictly speaking7 limited1 yet it is manifest that1 inasmuch as that increase depends on causes which are themselves approaching a limit1 its rate must1 after a time1 continually diminish4 ,let it be understood that1 when ,i speak of the requirements of the population1 ,i do not mean only what they must obtain from other countries4 ,the commerce of a country is the expression of the activity with which the nation is #8earning its living1' so to speak1 and in a given population there is a limit to what is necessary for this purpose1 precisely as there is a limit to the sum which an individual person in any given state of life requires for the maintenance of a given family4 ,indeed1 although such comparisons are not always safe1 we may in this case compare what may be called the commercial requirements of the nation with the requirements of the head of the family1--a merchant suppose4 ,there are no limits to the degree of wealth which a merchant may desire to gain1 but unquestionably there are limits to the income necessary to maintain his house and family and mercantile position4 ,supposing he were extending his gains far beyond his actual requirements1 it would by no means imply his approaching ruin that there was a demonstrable limit to this extension4 ,and in like manner1 it would seem that1 apart from the limits set by nature to the extension of our population1 it need by no means be assumed that if our commerce showed signs of approaching a limit1 the downfall of ,england's power would be at hand4 ,in fact1 we cannot accept ,mr4 ,jevons's figures for distant epochs without first inquiring whether it is likely that at those epochs the circumstances on which the consumption of our coal depends will be correspondingly changed4 ,supposing that #abj millions of tons of coals suffice for the requirements of our present population1 we can scarcely believe that #a1ddj millions will be needed in #aiej1 unless we suppose that the population of ,britain will be twelve times greater than at present2 or that the population will be even greater than this1 since the consumption of coal upon our railways could scarcely be expected to increase in proportion to the population4 ,now no one believes that ,britain will number #cjj millions of inhabitants in #aiej1 or in #biej2 the country could not maintain half that number1 even though all her available stores of coal and iron1 and other sources of commercial wealth were increased a hundredfold4 ,it is a mistake1 indeed1 to extend the results of statistical research very far beyond the time to which the facts and figures belong4 ,it would be easy to multiply instances of the incorrectness of such a process4 ,to take a single case4--,when cholera has been extending its ravages in this country1 the statistics of mortality from that cause1 if studied with reference to four or five successive weeks1 have indicated a law of increase1 which is very readily expressed so as to accord with the mortality during those weeks1 and perhaps two or three following weeks4 ,but if such a law were extended indefinitely it might be found to imply nothing short of the complete desolation of the country by cholera1 within the space of a few months4 ,thus1 if the deaths 7from cholera7 in five successive weeks were #bj1 #bg1 #ce1 #dg1 and #fc1--numbers corresponding with the general characteristics of cholera mortality in the earlier stages of a visitation1--the weekly mortality a year later1 estimated according to the observed percentage of increase1 would be more than #agc millions6 ,now this method of estimation1 though leading to this preposterous conclusion as respects a more distant epoch1 would probably lead to tolerably correct results for the next week or two after that in which #fc persons died1--the estimated numbers being #hd and #aaj for the next two weeks respectively4 ,it seems to me1 therefore1 that we are not justified1 by the observed seeming fulfilment of ,mr4 ,jevons's anticipations1 in concluding that a hundred years hence the consumption of coals will be #b1jjj millions of tons1 or that the total consumption during the next #aaj years will be #ajj1jjj millions of tons4 ,we might almost as safely infer that because a growing lad requires such and such an increase of food year by year1 the grown man will need a similar rate of increase1 and the septuagenarian require so many tons and hogsheads of solid and liquid food per diem4 ,at present it does not seem possible to arrive at any definite conclusions respecting the probable consumption of coal in years to come4 ,the range of observation is not sufficiently extended4 ,it seems clear1 indeed1 that the epoch is not near at hand when the present law of increase will be modified4 ,this is shown by the agreement of the observed results during the past five years with the anticipations of ,mr4 ,jevons4 ,it would be altogether unsafe to predict that the yearly consumption will not rise to #aej or #bjj or even #bej millions of tons per annum1 or to point to any definite stage at which the present increasing rate of increase will be changed first into uniform 7or arithmetical7 increase1 and thence into a decreasing rate of increase4 ,but it appears to me that no question can exist that these changes will take place4 ,we might even go farther1 and regard it as all but certain that the time will come when there will be no annual increase4 ,nay1 unless the history of this country is to differ from the history of all other nations which have attained to great power1 the time might be expected to arrive when there will be1 year by year1 a slow diminution in the commercial activity of ,britain1 and a corresponding diminution in the exhaustion of her coal stores4 ,there is room for an amazing increase in ,britain's power and greatness1 room also for an unprecedented continuance of these attributes1 while yet the coal stores of the country remain well supplied4 ,let us conceive1 for instance1 that the greatest annual consumption of coal during the future years of ,england's existence as a great nation1 should be set at three times her present annual consumption1 or at #cej millions of tons4 ,few will regard this as an unduly low estimate when they remember that it is exceedingly unlikely that the present population of ,britain will ever be tripled1 and that a triple population could be commercially far more active 7in relation to its numbers7 than the present population1 with no greater consumption of coal per head4 ,now1 to begin with1 if this enormous annual consumption began immediately1 we should yet 7with ,mr4 ,jevons's assumption as to the quantity of available coal7 have #egj years' lease of power instead of #aaj4 ,but1 as a matter of fact1 so soon as we have recognised the principle that there is a limit to the increase of annual consumption1 we are compelled to believe that that limit will be approached by a much gentler gradient1 so to speak1 than the same consumption as attained on ,mr4 ,jevons's assumption4 ,according to his view1 in fact1 an annual consumption of #cej millions of tons per annum will be attained early in the twentieth century2 but according to the theory which sets such a consumption as the highest ever to be attained1 we should place its attainment several hundreds of years later4 ,this is a vague statement1 ,i admit1 but the very fact on which ,i am mainly insisting is this1 that the evidence at present in our hands is insufficient as a basis of exact calculation4 ,now1 if we set #ejj years hence as the time when the annual consumption of coal will have reached the above enormous amount1 we should set the total consumption during those centuries at about one-half that due to an annual consumption of #cej millions of tons4 ,in that case there would still remain coal enough to supply the country for #cbj years at the same tremendous rate4 ,in all1 on these suppositions1 #hbj years would be provided for4 ,these would be years of commercial activity far exceeding that of our own day--in fact1 they would be years during which ,britain would be accumulating wealth at a rate so enormous that at the end of the era she would be not wholly unprovided with the means of supporting her existence as a nation1 apart from all reference to her mineral stores4 ,it is1 indeed1 utterly inconceivable1 ,i think1 that ,great ,britain and her people will ever be able to progress at the rate implied by these suggestions4 ,to conceive of ,great ,britain as arriving at ruin within a thousand years by the over-rapid exhaustion of her coal stores1 is1 in fact1 equivalent to supposing that she will attain in the interval to a wholly unprecedented--,i had almost said a wholly incredible--degree of wealth and power4 ,as regards the evidence which has been adduced respecting the extent of the available coal supply1 it is to be remarked that1 on the whole1 the result cannot be regarded as unfavourable4 ,the more sanguine views entertained five or six years ago have not1 indeed11 been fully justified4 ,yet our coal supply has been shown to be enormous1 even when considered with reference to the continually increasing exhaustion4 ,but it must be admitted that the question of the depth to which our coal mines may be conveniently or even possibly worked1 has an unpleasantly doubtful aspect4 ,of the stores which the ,commissioners regard as available a vast proportion must be mined out from depths far exceeding any which have been at present reached in ,england4 ,it is not as yet clear how far the increase of depth will add to the cost and risk of working2 nor do ,i propose to discuss a subject which can only be adequately dealt with by those who possess practical knowledge of the details of colliery-working4 ,i will content myself by quoting some remarks on the subject1 in an inaugural address delivered by ,mr4 ,george ,elliot 7one of the ,royal ,commissioners7 before the ,north of ,england ,institute of ,mining ,engineers in #ahfh4 #8,the great depth1' he remarked1 #8at which many of our pits are worked1 and the vast extent of their lateral ramifications1 make it more than ever necessary that we should secure the best mode of rendering the supply of pure air certain1 regular1 and safe4 ,it is maintained that ventilating by machinery ensures these desiderata2 that the nicety with which mechanical appliances may be regulated1 the delicate adjustment of power of which they are capable1 and the complete safety with which they may be worked1 place them far before the system they are intended to supersede4 ,the extent of our coal supply will be materially increased by the improvement of which this is a type4444 ,it is probable that the ordinary means of ventilation--whether by furnace or fan--may be aided by a change in the force or agency employed for the purposes of haulage and other independent work4 ,as an instance of my meaning1 ,i may mention that the apparatus which ,i have introduced in ,south ,wales1 and which1 by means of compressed air used as a motive power instead of steam1 draws trams and pumps water with complete success1 is found to generate ice in an atmosphere which is naturally hot and oppressive4 ,the mechanical usefulness of these new air-engines seems capable of indefinite extension2 while1 as their cooling properties form a collateral advantage arising out of their use1 it is at least possible that they may prove valuable auxiliaries to the more regular means of ventilation in extending the security and promoting the healthfulness of our mines4 ,the difficulties of ventilation once surmounted1 the extent of coal at our disposal is incalculably increased4#8 ,in the address just quoted there are some striking suggestions as to the possibility of working those coal fields which extend below the sea on our east and west coasts1 especially in the counties of ,durham1 ,northumberland1 and ,cumberland4 ,mr4 ,elliot remarks that #8for all practical purposes these fields are as entirely within the reach of the mining engineer as the ordinary workings out of which coal is hewed4' ,it is known that in many districts the coal strata extend ten or twelve miles beyond the shore2 and ,mr4 ,elliot believes that by sinking ventilating shafts in the ,german ,ocean the coal below may be safely worked4 ,the idea seems somewhat daring2 yet1 after the feats of engineering which have been achieved in our day1 there seems no valid reason for doubting that at least when the pressure of a failing coal supply begins to be felt1 the means will be found for rendering these immense submarine coal stores available4 ,as to the difficulty of transport1 ,mr4 ,elliot remarks that1 according to his estimates1 #8transport would neither be more costly nor more laborious than it has been in days gone by to convey coal the same distance after it was brought to the surface inland4' ,the enormous importance of the subject is shown by the fact that #8out of the minerals obtainable in ,durham alone1 one-third1' ,mr4 ,elliot tells us1 #8may be held to lie under the sea1 and that all coalfields having a similar inclination of strata1 and bordering on the ocean1 will be similarly enlarged4 ,this at once disposes1' he adds1 #8of some of the fears expressed as to the duration of our coal supply2 and while ,i am quite aware that these theories may be challenged1 they are not put forward without due deliberation1 and ,i am content to stake my professional reputation on their practicability4' ,with regard to the future of this country1 it appears to me that little anxiety need be entertained4 ,apart from the considerations ,i have urged1 which seem to indicate that our consumption cannot long increase at the same rate as at present1 it seems not unreasonable to anticipate that within the next few decades science will find the means of economising our coals in more ways than one4 ,it does not indeed appear likely that any form of fuel will ever take the place of coal2 but a portion of the work now derived from the consumption of coal may be expected to be derived in future years from some of the other substances now coming into use4 ,it may be hoped1 also1 that science may suggest means for bringing coals to the surface with less waste1 and even at less cost1 than at present4 ,and in other ways the process of exhaustion may be more or less effectively checked4 ,but while we may thus look somewhat confidently forward1 as ,i judge1 to the future of our country1 serious questions are suggested as to the future of the human race4 ,the period during which a nation flourishes1 long as it seems by comparison with the life of man1 yet sinks into insignificance when compared with the period during which civilised men will bear sway upon the earth4 ,the thousands of years during which the coal stores of the earth may be expected to last will pass away1 and then the descendants of those now living on the earth will have to trust to other force-supplies than those which we are now using so lavishly4 ,it may seem fanciful to look so far forward1 and yet by comparison with the periods which the astronomer deals with in considering the future of our earth1 thousands of years are as nothing4 ,as ,i have said elsewhere1 #8those thousands of years will pass as surely as the thousands which have already passed1 and the wants entailed by wastefulness in our day will then be felt1 and none the less that for so many years there had been no failure in the supplies contained within the great subterranean storehouse4' ,it behoves us to consider thoughtfully the wants even of those distant eras4 ,if the greatest good for the greatest number is to be regarded as the true rule for the conduct of intelligent beings1 then unquestionably mere distance in point of time should not prevent us from anticipating the requirements of those remote descendants of ours4 ,we should regard the consciousness of this duty and its performance as signs by which the superiority of our own over less civilised times is partly manifested4 ,as man is in dignity higher than non-intelligent animals1 in that he alone provides of his own forethought for the wants of his children1 so our generation would be raised in dignity above preceding generations if it took intelligent charge of the wants of its remote descendants4 ,we ourselves are now employing stores of force laid up for us by the unconscious processes of ,nature in long past ages4 ,as ,professor ,tyndall has finely said1 we are utilising the ,sun of the ,carboniferous ,epoch4 ,the light #8which streamed earthwards from the sun' was stored up for us by the unconscious activity of #8organisms which living took into them the solar light1 and by the consumption of its energy incessantly generated chemical forces4' ,the vegetable world of that old epoch #8constituted the reservoir in which the fugitive solar rays were fixed1 suitably deposited1 and rendered ready for useful application4' ,what the vegetable world did for us unconsciously during the ,carboniferous ,epoch1 the scientific world of our epoch must do for our remote descendants4 ,while we are consuming the stores of force laid up in past ages for our benefit1 we must invent the means for obtaining directly from the solar rays fresh and inexhaustible supplies of motive energy4 7,from the ,st4 ,paul's ,magazine1 ,november #ahga47 ,,the ,,secret ,,of ,,the ,,north ,,pole4 ,if an astronomer upon some distant planet has ever thought the tiny orb we inhabit worthy of telescopic study1 there can be little doubt that the snowy regions which surround the arctic and antarctic poles must have attracted a large share of his attention4 ,waxing and waning with the passing seasons1 those two white patches afford significant information respecting the circumstances of our planet's constitution4 ,they mark the direction of the imaginary axial line upon which the planet rotates2 so that we can imagine that an astronomer on ,mars or ,venus would judge from their position how it fares with terrestrial creatures4 ,there may1 indeed1 be ,martial ,whewells who laugh to scorn the notion that a globe so inconveniently circumstanced as ours can be inhabited1 and are ready to show that1 if there were living beings here1 they must be quickly destroyed by excessive heat4 ,on the other hand1 there are possibly sceptics on ,venus also who smile at the vanity of those who can conceive a frozen world1 such as this our outer planet1 to be inhabited by any sort of living creature4 ,but we doubt not that the more advanced thinkers both in ,mars and ,venus are ready to admit that1 though we must necessarily be far inferior beings to themselves1 we yet manage to #8live and move and have our being' on this ill-conditioned globe of ours4 ,and these1 observing the earth's polar snow-caps1 must be led to several important conclusions respecting physical relations here4 ,it is1 indeed1 rather a singular fact to contemplate1 that ex-terrestrial observers1 such as these1 may know much more than we ourselves do respecting those mysterious regions which lie close around the two poles4 ,their eyes may have rested on spots which1 with all our endeavours1 we have hitherto failed to reach4 ,whether1 as some have thought1 the arctic pole is in summer surrounded by a wide and tide-swayed ocean2 whether there lies around the antarctic pole a wide continent bespread with volcanic mountains larger and more energetic than the two burning cones which ,ross found on the outskirts of this desolate region2 or whether the habitudes prevailing near either pole are wholly different from those suggested by geographers and voyagers--such questions as these might possibly1 be resolved at once1 could our astronomers take their stand on some neighbouring planet1 and direct the searching power of their telescopes upon this terrestrial orb4 ,for this is one of those cases referred to by ,humboldt1 when he said that there are circumstances under which man is able to learn more respecting objects millions of miles away from him than respecting the very globe which he inhabits4 ,if we take a terrestrial globe1 and examine the actual region near the ,north ,pole which has as yet remained unvisited by man1 it will be found to be far smaller than many imagine4 ,in nearly all maps the requirements of charting result in a considerable exaggeration of the polar regions4 ,this is the case in the ordinary #8maps of the two hemispheres' which are to be found in all atlases4 ,and it is1 of course1 the case to a much more remarkable extent in what is termed ,mercator's projection4 ,in a ,mercator's chart we see ,greenland1 for example1 exaggerated into a continent fully as large as ,south ,america1 or to seven or eight times its real dimensions4 ,there are three principal directions in which explorers have attempted to approach the ,north ,pole4 ,the first is that by way of the sea which lies between ,greenland and ,spitzbergen4 ,i include under this head ,sir ,edward ,parry's attempt to reach the pole by crossing the ice-fields which lie to the north of ,spitzbergen4 ,the second is that by way of the straits which lie to the west of ,greenland4 ,the third is that pursued by ,russian explorers who have attempted to cross the frozen seas which surround the northern shores of ,siberia4 ,in considering the limits of the unknown north-polar regions1 we shall also have to take into account the voyages which have been made around the northern shores of the ,american continent in the search for a #8north-west passage4' ,the explorers who set out upon this search found themselves gradually forced to seek higher and higher latitudes in order to find a way round the complicated barriers presented by the ice-bound straits and islands which lie to the north of the ,american continent4 ,and it may be noticed in passing1 as a remarkable and unforeseen circumstance1 that the farther north the voyagers went the less severe was the cold they had to encounter4 ,we shall see that this circumstance has an important bearing on the considerations ,i shall presently have to deal with4 ,one other circumstance respecting the search for the north-west passage1 though not connected very closely with my subject1 is so singular and so little known that ,i feel tempted to make mention of it at this point4 ,the notion with which the seekers after a north-west passage set out was simply this1 that the easiest way of reaching ,china and the ,east ,indies was to pursue a course resembling as near as possible that on which ,columbus had set out--if only it should appear that no impassable barriers rendered such a course impracticable4 ,they quickly found that the ,american continent presents an unbroken line of land from high northern latitudes far away towards the antarctic seas4 ,but it is a circumstance worth noticing1 that if the ,american continents had no existence1 the direct westerly course pursued by ,columbus was not only not the nearest way to the ,east ,indian ,archipelago1 but was one of the longest routes which could possibly have been selected4 ,surprising as it may seem at first sight1 a voyager from ,spain for ,china and the ,east ,indies ought1 if he sought the absolutely shortest path1 to set out on an almost direct northerly route6 ,he would pass close by ,ireland and ,iceland1 and onwards past the ,north ,pole into the ,pacific4 ,this is what is called the great-circle route2 and if it were only practicable one1 would shorten the journey to ,china by many hundreds of miles4 ,let us return1 however1 to the consideration of the information which arctic voyagers have brought us concerning the north-polar regions4 ,the most laborious researches in arctic seas are those which have been carried out by the searchers after a north-west passage4 ,i shall therefore first consider the limits of the unknown region in this direction4 ,afterwards we can examine the results of those voyages which have been undertaken with the express purpose of reaching the ,north ,pole along the three principal routes already mentioned4 ,if we examine a map of ,north ,america constructed in recent times1 we shall find that between ,greenland and ,canada an immense extent of coast-line has been charted4 ,a vast archipelago covers this part of the northern world4 ,or1 if the strangely-complicated coastlines which have been laid down really belong to but a small number of islands1 the figures of those must be of the most fantastic kind4 ,towards the north-west1 however1 we find several islands whose outlines have been entirely ascertained4 ,thus we have in succession ,north ,devon ,island1 ,cornwallis ,island1 ,melville ,island1 and ,port ,patrick ,island1 all lying north of the seventy-fifth parallel of latitude4 ,but we are not to suppose that these islands limit the extent of our seamen's researches in this direction4 ,far to the northward of ,wellington ,channel1 ,captain de ,haven saw1 in #aheb1 the signs of an open sea--in other words1 he saw1 beyond the ice-fields1 what arctic seamen call a #8water sky4' ,in #ahee ,captain ,penny sailed upon this open sea2 but how far it extends towards the ,north ,pole has not yet been ascertained4 ,it must not be forgotten that the north-west passage has been shown to be a reality1 by means of voyages from the ,pacific as well as from the ,atlantic4 ,no arctic voyager1 however1 has yet succeeded in passing from one ocean to the other4 ,nor is it likely now that any voyager will pursue his way along a path so beset by dangers as that which is called the north-west passage4 ,long before the problem had been solved1 it had become well known that no profit could be expected to accrue to trade from the discovery of a passage along the perilous straits and the ice-encumbered seas which1 lie to the north of the ,american continent4 ,but ,sir ,edward ,parry having traced out a passage as far as ,melville ,island1 it seemed to the bold spirit of our arctic explorers that it might be possible1 by sailing through ,behring's ,straits1 to trace out a connection between the arctic seas on that side and the regions reached by ,parry4 ,accordingly1 ,m',clure1 in #ahej1 sailed in the #8,investigator1' and passing eastward1 after traversing ,behring's ,straits1 reached ,baring's ,land1 and eventually identified this land as a portion of ,banks' ,land1 seen by ,parry to the southward of ,melville ,island4 ,it will thus be seen that the unexplored parts of the arctic regions are limited in this direction by sufficiently high latitudes4 ,turn we next to the explorations which ,russian voyagers have made to the northward of ,siberia4 ,it must be noticed1 in the first place1 that the coast of ,siberia runs much farther northward than that of the ,american continent4 ,so that on this side1 independently of sea explorations1 the unknown arctic regions are limited within very high latitudes4 ,but attempts have been made to push much farther north from these shores4 ,in every case1 however1 the voyagers have found that the ice-fields1 over which they hoped to make their way1 have become gradually less and less firm1 until at length no doubt could remain that there lay an open sea beyond them4 ,how far that sea may extend is a part of the secret of the ,north ,pole2 but we may assume that it is no narrow sea1 since otherwise there can be little doubt that the ice-fields which surround the shores of ,northern ,siberia would extend unbroken to the farther shores of what we should thus have to recognise as a strait4 ,the thinning-off of these ice-fields1 observed by ,baron ,wrangel and his companions1 affords1 indeed1 most remarkable and significant testimony respecting the nature of the sea which lies beyond4 ,this ,i shall presently have to exhibit more at length2 in the meantime ,i need only remark that scarcely any doubt can exist that the sea thus discovered extends northwards to at least the eightieth parallel of latitude4 ,we may say1 then1 that from ,wellington ,channel1 northward of the ,american continent1 right round towards the west1 up to the neighbourhood of ,spitzbergen1 very little doubt exists as to the general characteristics of the arctic regions1 save only as respects those unexplored parts which lie within ten or twelve degrees of the ,north ,pole4 ,the reader will see presently why ,i am so careful to exhibit the limited extent of the unexplored arctic regions in this direction4 ,the guess we shall form as to the true nature of the north-polar secret will depend almost entirely on this consideration4 ,i turn now to those two paths along which arctic exploration1 properly so termed1 has been most successfully pursued4 ,it is chiefly to the expeditions of ,drs4 ,kane and ,hayes that we owe the important knowledge we have respecting the northerly portions of the straits which lie to the west of ,greenland4 ,each of these explorers succeeded in reaching the shores of an open sea lying to the north-east of ,kennedy ,channel1 the extreme northerly limit of those straits4 ,hayes1 who had accompanied ,kane in the voyage of #ahed-e1 succeeded in reaching a somewhat higher latitude in sledges drawn by ,esquimaux dogs4 ,but both expeditions agree in showing that the shores of ,greenland trend off suddenly towards the east at a point within some nine degrees of the ,north ,pole4 ,on the other hand1 the prolongation of the opposite shore of ,kennedy ,channel was found to extend northwards as far as the eye could reach4 ,within the angle thus formed there was an open sea #8rolling1' says ,captain ,maury1 #8with the swell of a boundless ocean4' ,but a circumstance was noticed respecting this sea which was very significant4 ,the tides ebbed and flowed in it4 ,only one fact we know of--a fact to be presently discussed--throws so much light on the question we are considering as this circumstance does4 ,let us consider a little whence these tidal waves can have come4 ,the narrow straits between ,greenland on the one side1 and ,ellesmere ,land and ,grinnell ,land on the other1 are completely ice-bound4 ,we cannot suppose that the tidal wave could have found its way beneath such a barrier as this4 #8,i apprehend1' says ,captain ,maury1 #8that the tidal wave from the ,atlantic can no more pass under this icy barrier1 to be propagated in the seas beyond1 than the vibrations of a musical string can pass with its notes a fret on which the musician has placed his finger4' ,are we to suppose1 then1 that the tidal waves were formed in the very sea in which they were seen by ,kane and ,hayes8 ,this is ,captain ,maury's opinion3--#8,these tides1' says he1 #8must have been born in that cold sea1 having their cradle about the ,north ,pole4' ,but if we carefully consider the theory of the tides1 this opinion seems inadmissible4 ,every consideration on which that theory is founded is opposed to the assumption that the moon could by any possibility raise tides in an arctic basin of limited extent4 ,it would be out of place to examine at length the principle on which the formation of tides depends4 ,it will be sufficient for our purposes to remark that it is not to the mere strength of the moon's #8pull' upon the waters of any ocean that the tidal wave owes its origin1 but to the difference of the forces by which the various parts of that ocean are attracted4 ,the whole of an ocean cannot be raised at once by the moon2 but if one part is attracted more than another1 a wave is formed4 ,that this may happen1 the ocean must be one of wide extent4 ,in the vast seas which surround the ,southern ,pole there is room for an immensely powerful #8drag1' so to speak2 for always there will be one part of these seas much nearer to the moon than the rest1 and so there will be an appreciable difference of pull upon that part4 ,the reader will now see why ,i have been so careful to ascertain the limits of the supposed north-polar ocean1 in which1 according to ,captain ,maury1 tidal waves are generated4 ,to accord with his views1 this ocean must be surrounded on all sides by impassable barriers either of land or ice4 ,these barriers1 then1 must lie to the northward of the regions yet explored1 for there is open sea communicating with the ,pacific all round the north of ,asia and ,america4 ,it only requires a moment's inspection of a terrestrial globe to see how small a space is thus left for ,captain ,maury's land-locked ocean4 ,i have purposely left out of consideration1 as yet1 the advances made by arctic voyagers in the direction of the sea which lies between ,greenland and ,spitzbergen4 ,we shall presently see that on this side the imaginary land-locked ocean must be more limited than towards the shores of ,asia or ,america4 ,as it is1 however1 it remains clear1 that if there were any ocean communicating with the spot reached by ,dr4 ,kane1 but separated from all communication--by open water--either with the ,atlantic or with the ,pacific1 that ocean would be so limited in extent that the moon's attraction could exert no more effective influence upon its waters than upon the waters of the ,mediterranean--where1 as we know1 no tides are generated4 ,this1 then1 would be a tideless ocean1 and we must look elsewhere for an explanation of the tidal waves seen by ,dr4 ,kane4 ,we thus seem to have prim facie evidence that the sea reached by ,kane communicates either with the ,pacific or with the ,atlantic1 or--which is the most probable view--with both those oceans4 ,when we consider the voyages which have been made towards the ,north ,pole along the northerly prolongation of the ,atlantic ,ocean1 we find very strong evidence in favour of the view that there is open-water communication in this direction1 not only with the spot reached by ,kane1 but with a region very much nearer to the ,north ,pole4 ,so far back as #afjg1 ,hudson had penetrated within eight and a half degrees 7or about #fjj miles7 of the ,north ,pole on this route4 ,when we consider the clumsy build and the poor sailing qualities of the ships of ,hudson's day1 we cannot but feel that so successful a journey marks this route as one of the most promising ever tried4 ,hudson was not turned back by impassable barriers of land or ice1 but by the serious dangers to which the floating masses of ice and the gradually thickening ice-fields exposed his weak and ill-manned vessel4 ,since his time1 others have sailed upon the same track1 and hitherto with no better success4 ,it was reserved to the ,swedish expedition of #ahfh to gain the highest latitudes ever reached in a ship in this direction4 ,the steamship #8,sofia1' in which this successful voyage was made1 was strongly built of ,swedish iron1 and originally intended for winter voyages in the ,baltic4 ,owing to a number of delays1 it was not until ,september #af that the #8,sofia' reached the most northerly part of her journey4 ,this was a point some fifteen miles nearer the ,north ,pole than ,hudson had reached4 ,to the north there still lay broken ice1 but packed so thickly that not even a boat could pass through it4 ,so late in the season1 it would have been unsafe to wait for a change of weather and a consequent breaking-up of the ice4 ,already the temperature had sunk sixteen degrees below the freezing-point2 and the enterprising voyagers had no choice but to return4 ,they made1 indeed1 another push for the north a fortnight later1 but only to meet with a fresh repulse4 ,an ice-block with which they came into collision opened a large leak in the vessel's side2 and when after great exertions they reached the land1 the water already stood two feet over the cabin floor4 ,in the course of these attempts1 the depths of the ,atlantic were sounded1 and two interesting facts were revealed4 ,the first was that the island of ,spitzbergen is connected with ,scandinavia by a submarine bank2 the second was the circumstance that to the north and west of ,spitzbergen the ,atlantic is more than two miles deep6 ,we come now to the most conclusive evidence yet afforded of the extension of the ,atlantic ,ocean towards the immediate neighbourhood of the ,north ,pole4 ,singularly enough1 this evidence is associated not with a sea-voyage1 nor with a voyage across ice to the borders of some northern sea1 but with a journey during which the voyagers were throughout surrounded as far as the eye could reach by apparently fixed ice-fields4 ,in #ahbg ,sir ,edward ,parry was commissioned by the ,english ,government to attempt to reach the ,north ,pole4 ,a large reward was promised in case he succeeded1 or even if he could get within five degrees of the ,north ,pole4 ,the plan which he adopted seemed promising4 ,starting from a port in ,spitzbergen1 he proposed to travel as far northward as possible in sea-boats1 and then1 landing upon the ice1 to prosecute his voyage by means of sledges4 ,few narratives of arctic travel are more interesting than that which ,parry has left of this famous #8boat-and-sledge' expedition4 ,the voyagers were terribly harassed by the difficulties of the way2 and after a time1 that most trying of all arctic experiences1 the bitterly cold wind which comes from out the dreadful north1 was added to their trials4 ,yet still they plodded steadily onwards1 tracking their way over hundreds of miles of ice with the confident expectation of at least attaining to the eighty-fifth parallel1 if not to the ,pole itself4 ,but a most grievous disappointment was in store for them4 ,parry began to notice that the astronomical observations1 by which in favourable weather he estimated the amount of their northerly progress1 showed a want of correspondence with the actual rate at which they were travelling4 ,at first he could hardly believe that there was not some mistake2 but at length the unpleasant conviction was forced upon him that the whole ice-field over which he and his companions had been toiling so painfully was setting steadily southwards before the wind4 ,each day the extent of this set became greater and greater1 until at length they were actually carried as fast towards the south as they could travel northwards4 ,parry deemed it useless to continue the struggle4 ,there were certainly two chances in his favour4 ,it was possible that the north wind might cease to blow1 and it was also possible that the limit of the ice might soon be reached1 and that his boats might travel easily northward upon the open sea beyond4 ,but he had to consider the exhausted state of his men1 and the great additional danger to which they were subjected by the movable nature of the ice-fields4 ,if the ice should break up1 or if heavy and long-continued southerly winds should blow1 they might have found it very difficult to regain their port of refuge in ,spitzbergen before winter set in or their stores were exhausted4 ,besides1 there were no signs of water in the direction they had been taking4 ,the water-sky of arctic regions can be recognised by the experienced seamen long before the open sea itself is visible4 ,on every side1 however1 there were the signs of widely-extended ice-fields4 ,it seemed1 therefore1 hopeless to persevere1 and ,parry decided on returning with all possible speed to the haven of refuge prepared for the party in ,spitzbergen4 ,he had succeeded in reaching the highest northern latitudes ever yet attained by man4 7,a somewhat higher latitude has since been reached by ,captain ,nares's expedition47 ,the most remarkable feature of this expedition1 however1 is not the high latitude which the party attained1 but the strange circumstance which led to their discomfiture4 ,what opinion are we to form of an ocean at once wide and deep enough to float an ice-field which must have been thirty or forty thousand square miles in extent8 ,parry had travelled upwards of three hundred miles across the field1 and we may fairly suppose that he might have travelled forty or fifty miles farther without reaching open water2 also that the field extended fully fifty miles on each side of ,parry's northerly track4 ,that the whole of so enormous a field should have floated freely before the arctic winds is indeed an astonishing circumstance4 ,on every side of this floating ice-island there must have been seas comparatively free from ice2 and could a stout ship have forced its way through these seas1 the latitudes to which it could have reached would have been far higher than those to which ,parry's party was able to attain4 ,for a moment's consideration will show that the part of the great ice-field where ,parry was compelled to turn back must have been floating in far higher latitudes when he first set out4 ,he reckoned that he had lost more than a hundred miles through the southerly motion of the ice-field1 and by this amount1 of course1 the point he reached had been nearer the ,pole4 ,it is not assuming too much to say that a ship which could have forced its way round the great floating ice-field would certainly have been able to get within four degrees of the ,pole4 ,it seems to us highly probable that she would even have been able to sail upon open water to and beyond the ,pole itself4 ,and when we remember the direction in which ,dr4 ,kane saw an open sea--namely1 towards the very region where ,parry's ice--ship had floated a quarter of a century before--it seems reasonable to conclude that there is open water communication between the seas which lie to the north of ,spitzbergen and those which lave the north-western shores of ,greenland4 ,if this be so1 we at once obtain an explanation of the tidal waves which ,kane watched day after day in #ahee4 ,these had no doubt swept along the valley of the ,atlantic1 and thence around the northern coast of ,greenland4 ,it follows that1 densely as the ice may be packed at times in the seas by which ,hudson1 ,scoresby1 and other captains have attempted to reach the ,north ,pole1 the frozen masses must in reality be floating freely1 and there must therefore exist channels through which an adventurous seaman might manage to penetrate the dangerous barriers surrounding the polar ocean4 ,in such an expedition1 chance unfortunately plays a large part4 ,whalers tell us that there is great uncertainty as to the winds which may blow during an arctic summer4 ,the icebergs may be crowded by easterly winds upon the shores of ,greenland1 or by westerly winds upon the shores of ,spitzbergen1 or1 lastly1 the central passage may be the most encumbered1 through the effects of winds blowing now from the east and now from the west4 ,thus the arctic voyager has not merely to take his chance as to the route along which he shall adventure northwards1 but often1 after forcing his way successfully for a considerable distance1 he finds the ice-fields suddenly closing in upon him on every side1 and threatening to crush his ship into fragments4 ,the irresistible power with which1 under such circumstances1 the masses of ice bear down upon the stoutest ship1 has been evidenced again and again2 though1 fortunately1 it not unfrequently happens that some irregularity along one side or the other of the closing channel serves as a sort of natural dock1 within which the vessel may remain in comparative safety until a change of wind sets her free4 ,instances have been known in which a ship has had so narrow an escape in this way1 and has been subjected to such an enormous pressure1 that when the channel was opened out again1 the impress of the ship's side has been seen distinctly marked upon the massive blocks of ice which have pressed against her4 7,from the ,st4 ,paul's ,magazine1 ,june #ahfi47 ,,footnotes3 #e ,so far back as #aghi1 ,john ,williams1 in his ,natural ,history of the ,mineral ,kingdom1 discussed the question of the #8,limited ,quantity of ,coal in ,great ,britain4' ,the following extracts are taken from an excellent paper on the exhaustion of our coal in the ,popular ,science ,review for ,july #ahff1 by ,mr4 ,lemoran1 ,colliery ,viewer4 #8,i have no doubt1' says ,williams1 #8that the generality of the inhabitants of ,great ,britain believe that our coal mines are inexhaustible2 and the general conduct of the nation1 so far as relates to this subject1 seems to imply that this is held as an established fact4 ,if it was not a generally received opinion1 would the rage for exporting coals be allowed to go on without limitation or remorse8 ,but it is full time that the public were undeceived in a matter which so nearly concerns the welfare of this flourishing island4444 ,when our coal mines are exhausted1 the prosperity and glory of this flourishing and fortunate island are at an end4 ,our cities and great towns must then become ruinous heaps for want of fuel1 and our mines and manufactories must fail from the same cause1 and then1 consequently1 our commerce must vanish4 ,in short1 the commerce1 wealth1 importance1 glory1 and happiness of ,great ,britain will decay and gradually dwindle away to nothing1 in proportion as our coal and other mines fail4' ,mr4 ,williams also solves in a very summary manner the problem of ,england's fate after her coal stores shall be exhausted4 #8,the future inhabitants of this island must live1' says he1 #8like its first inhabitants1 by fishing and hunting4' #f ,in #ahed1 the yield was #fd1ffa1dja tons2 in #ahfd1 the yield was #ib1ghg1hgc3 the average increase per annum was1 therefore1 no less than #b1hab1fdg tons4 #g ,i have obtained a somewhat different result from a computation ,i have just gone through4 ,i make the consumption #bia millions in #aijj1 and #a1ddf millions in #aiej4 ,mr4 ,lemoran seems to have taken the percentage at #c instead of #c4 ,it is worth noticing how seriously a small change in the percentage affects the result2 the consumption in #aiej becoming #a1gfj millions of tons1 instead of #a1ddf millions4 #h ,the year #ahfc was the last whose statistics were available for ,mr4 ,jevons's purpose2 and estimating from either #ahfj or #ahfb would give a result smaller than either of the above4 ,indeed1 the consumption was less in #ahfb than in #ahfa4 ,,is ,,the ,,gulf ,,stream ,a ,,myth8 ,the ,gulf ,stream has recently attracted a large share of the attention of our men of science4 ,the strange weather which we experienced last winter 7see date of essay7 has had something to do with this4 ,the influence of the ,gulf ,stream upon our climate1 and the special influence which it is assumed to exercise in mitigating the severity of our winters1 have been so long recognised that meteorologists began to inquire what changes could be supposed to have taken place in the great current to account for so remarkable a winter as the last4 ,but it happened also that at a meeting of the ,royal ,geographical ,society early in the present year the very existence of the ,gulf ,stream was called in question1 just when meteorologists were disposed to assign to it effects of unusual importance4 ,and in the course of the discussion whether there is in truth a ,gulf ,stream--or rather whether our shores are visited by a current which merits such a name--a variety of interesting facts were adduced1 which were either before unknown or had attracted little attention4 ,as at a recent meeting of the same society these doubts have been renewed1 ,i propose to examine briefly1 in the first place1 a few of the considerations which have been urged against the existence of a current from the ,gulf of ,mexico to the neighbourhood of our shores2 and then1 having rehabilitated the reputation of this celebrated ocean river--as ,i believe ,i shall be able to do--,i shall proceed to give a brief sketch of the processes by which the current-system of the ,north ,atlantic is set and maintained in motion4 ,in reality the ,gulf ,stream is only a part of a system of oceanic circulation2 but in dealing with the arguments which have been urged against its very existence1 we may confine our attention to the fact that1 according to the views which had been accepted for more than a century1 there is a stream of water which1 running out of the ,gulf ,stream through the ,narrows of ,bemini1 flows along the shores of the ,united ,states to ,newfoundland1 and thence right across the ,atlantic to the shores of ,great ,britain4 ,it is this last fact which is now called in question4 ,the existence of a current as far as the neighbourhood of ,newfoundland is conceded1 but the fact that the stream flows onward to our shores is denied4 ,the point on which most stress is placed is the shallowness of the passage called the #8,bemini ,narrows1' through which it is assumed that the whole of the ,gulf current must pass4 ,this passage has a width of about forty miles1 and a depth of little more than six hundred yards4 ,the current which flows through it is perhaps little more than thirty miles in width1 and a quarter of a mile in depth4 ,it is asked with some appearance of reason1 how this narrow current can be looked upon as the parent of that wide stream which is supposed to traverse the ,atlantic with a mean width of some five or six hundred miles4 ,indeed1 a much greater width has been assigned to it1 though on mistaken grounds2 for it has been remarked that since waifs and strays from the tropics are found upon the shores of ,portugal1 as well as upon those of ,greenland1 we must ascribe to the current a span equal to the enormous space separating these places4 ,but the circumstance here dwelt upon can clearly be explained in another way4 ,we know that of two pieces of wood thrown into the ,thames at ,richmond1 one might be picked up at ,putney1 and the other at ,gravesend4 ,yet we do not conclude that the width of the ,thames is equal to the distance separating ,putney from ,gravesend4 ,and doubtless the tropical waifs which have been picked up on the shores of ,greenland and of ,portugal have found their way thither by circuitous courses1 and not by direct transmission along opposite edges of the great ,gulf current4 ,but certainly the difficulty associated with the narrowness of the ,bemini current is one deserving of careful attention4 ,are we free to identify a current six hundred miles in width with one which is but thirty miles wide1 and not very deep8 ,an increase of width certainly not less than thirtyfold would appear to correspond to a proportionate diminution of depth4 ,and remembering that it is only near the middle of the ,narrows that the ,gulf ,stream has a depth of four hundred yards1 we could scarcely assign to the wide current in the mid-,atlantic a greater depth than ten or twelve yards4 ,this depth seems altogether out of proportion to the enormous lateral extension of the current4 ,but besides that even this consideration would not suffice to disprove the existence of a current in the mid-,atlantic1 an important circumstance remains to be mentioned4 ,the current in the ,narrows flows with great velocity1--certainly not less than four or five miles an hour4 ,as the current grows wider it flows more sedately2 and opposite ,cape ,hatteras its velocity is already reduced to little more than three miles an hour4 ,in the mid-,atlantic the current may be assumed to flow at a rate little exceeding a mile per hour1 at the outside4 ,here1 then1 we have a circumstance which suffices to remove a large part of the difficulty arising from the narrowness of the ,bemini current1 and we can at once increase our estimate of the depth of the mid-,atlantic current fivefold4 ,but this is not all4 ,it has long been understood that the current which passes out through the ,narrows of ,bemini corresponds to the portion of the great equatorial current which passes into the ,gulf of ,mexico between the ,west ,indian ,islands4 ,we cannot doubt that the barrier formed by those islands serves to divert a large portion of the equatorial current4 ,the portion thus diverted finds its way1 we may assume1 along the outside of the ,west ,indian ,archipelago1 and thus joins the other portion--which has in the meantime made the circuit of the ,gulf--as it issues from the ,bemini ,straits4 ,all the maps in which the ,atlantic currents are depicted present precisely such an outside current as ,i have here spoken of1 and most of them assign to it a width exceeding that of the ,bemini current4 ,indeed1 were it not for the doubts which the recent discussions have thrown upon all the currents charted by seamen1 ,i should have been content to point to this outside current as shown in the maps4 ,as it is1 ,i have thought is necessary to show that such a current must necessarily have an existence1 since we cannot lose sight of the influence of the ,west ,indian ,isles in partially damming up the passage along which the equatorial current would otherwise find its way into the ,gulf of ,mexico4 ,whatever portion of the great current is thus diverted must find a passage elsewhere1 and no passage exists for it save along the outside of the ,west ,indian ,isles4 ,the possibility that the wide current which has been assumed to traverse the mid-,atlantic may be associated with the waters which flow from the ,gulf of ,mexico1 either through the ,narrows or round the outside of the barrier formed by the ,west ,indies1 has thus been satisfactorily established4 ,but we now have to consider difficulties which have been supposed to encounter our current on its passage from the ,gulf to the mid-,atlantic4 ,northwards1 along the shores of the ,united ,states1 the current has been traced by the singular blueness of its waters until it has reached the neighbourhood of ,newfoundland4 ,over a part of this course1 indeed1 the waters of the current are of indigo blue1 and so clearly marked that their line of junction with the ordinary sea-water can be traced by the eye4 #8,often1' says ,captain ,maury1 #8one half of a vessel may be perceived floating in ,gulf ,stream water1 while the other half is in common water of the sea--so sharp is the line1 and such the want of affinity between the waters1 and such1 too1 the reluctance1 so to speak1 on the part of those of the ,gulf ,stream1 to mingle with the littoral waters of the sea4' ,but it is now denied that there is any current beyond the neighbourhood of ,newfoundland--or that the warm temperature1 which has characterised the waters of the current up to this point1 can be detected farther out4 ,it is first noticed that1 as the ,gulf current must reach the neighbourhood of ,newfoundland with a north-easterly motion1 and1 if it ever reached the shores of the ,british ,isles1 would have to travel thither with an almost due easterly motion1 there is a change of direction to be accounted for4 ,this1 however1 is an old1 and ,i had supposed exploded1 fallacy4 ,the course of the ,gulf ,stream from the ,bemini ,straits to the ,british ,isles corresponds exactly with that which is due to the combined effects of the motion of the water and that of the earth upon its axis4 ,florida being much nearer than ,ireland to the equator1 has a much more rapid easterly motion4 ,therefore1 as the current gets farther and farther north1 the effect of the easterly motion thus imparted to it begins to show itself more and more1 until the current is gradually changed from a north-easterly to an almost easterly stream4 ,the process is the exact converse of that by which the air-currents from the north gradually change into the north-westerly trade-winds as they get farther south4 ,but it is further remarked that as the current passes out beyond the shelter of ,newfoundland1 it is impinged upon by those cold currents from the arctic seas which are known to be continually flowing out of ,baffin's ,bay and down the eastern shores of ,greenland2 and it is contended that these currents suffice1 not merely to break up the ,gulf current1 but so to cool its waters that these could produce no effect upon the climate of ,great ,britain if they ever reached its neighbourhood4 ,here1 again1 ,i must remark that we are dealing with no new discovery4 ,captain ,maury has already remarked upon this peculiarity4 #8,at the very season of the year1' he says1 #8when the ,gulf ,stream is rushing in greatest volume through the ,straits of ,florida1 and hastening to the north with the greatest rapidity1 there is a cold stream from ,baffin's ,bay1 ,labrador1 and the coasts of the north1 running south with equal velocity4444 ,one part of it underruns the ,gulf ,stream1 as is shown by the icebergs1 which are carried in a direction tending across its course4' ,there can be no doubt1 in fact1 that this last circumstance indicates the manner in which the main contest between the two currents is settled4 ,a portion of the arctic current finds its way between the ,gulf ,stream and the continent of ,america2 and this portion1 though narrow1 has a very remarkable effect in increasing the coldness of the ,american winters4 ,but the main part1 7heavier1 by reason of its coldness1 than the surrounding water17 sinks beneath the surface4 ,and the well-known fact mentioned by ,maury1 that icebergs have been seen stemming the ,gulf ,stream1 suffices to show how comparatively shallow that current is at this distance from its source1 and thus aids to remove a difficulty which we have already had occasion to deal with4 ,doubtless the cooling influence of the arctic currents is appreciable2 but it would be a mistake to suppose that this influence can suffice to deprive the ,gulf current of its distinctive warmth4 ,if all the effect of the cold current were operative on the ,gulf ,stream alone we might suppose that1 despite the enormous quantity of comparatively warm water which is continually being carried northwards1 the current would be reduced to the temperature of the surrounding water4 ,but this is not so4 ,the arctic current not only cools the ,gulf current1 but the surrounding water also--possibly to a greater extent1 for it is commonly supposed that a bed of ordinary sea-water separates the two main currents from each other4 ,thus the characteristic difference of temperature remains unaffected4 ,but in reality we may assume that the cooling effect actually exercised by the arctic current upon the neighbouring sea is altogether disproportionate to the immense amount of heat continually being carried northwards by the ,gulf ,stream4 ,it is astonishing how unreadily two sea-currents exchange their temperatures--to use a somewhat inexact mode of expression4 ,the very fact that the littoral current of the ,united ,states is so cold--a fact thoroughly established--shows how little warmth this current has drawn from the neighbouring seas4 ,another fact1 mentioned by ,captain ,maury1 bears in a very interesting manner upon this peculiarity4 ,he says3 #8,if any vessel will take up her position a little to the northward of ,bermuda1 and steering thence for the capes of ,virginia1 will try the water-thermometer all the way at short intervals1 she will find its reading to be now higher1 now lower2 and the observer will discover that he has been crossing streak after streak of warm and cool water in regular alternations4' ,each portion maintains its own temperature1 even in the case of such warm streaks as these1 all belonging to one current4 ,similar considerations dispose of the arguments which have been founded on the temperature of the sea-bottom4 ,it has been proved that the living creatures which people the lower depths of the sea exist under circumstances which evidence a perfect uniformity of temperature2 and arguments on the subject of the ,gulf ,stream have been derived from the evidence of what is termed a minimum thermometer--that is1 a thermometer which will indicate the lowest temperature it has been exposed to--let down into the depths of the sea4 ,all such arguments1 whether adduced against or in favour of the ,gulf ,stream theory1 must be held1 to be futile1 since the thermometer in its descent may pass through several submarine currents of different temperature4 ,lastly1 an argument has been urged against the warming effects of the ,gulf ,stream upon our climate which requires to be considered with some attention4 ,it is urged that the warmth derived from so shallow a current as the ,gulf ,stream must be1 by the time it has reached our shores1 could not provide an amount of heat sufficient to affect our climate to any appreciable extent4 ,the mere neighbourhood of this water at a temperature slightly higher than that due to the latitude could not1 it is urged1 affect the temperature of the inland counties at all4 ,this argument is founded on a misapprehension of the beautiful arrangement by which ,nature carries heat from one region to distribute it over another4 ,over the surface of the whole current the process of evaporation is going on at a greater rate than over the neighbouring seas1 because the waters of the current are warmer than those which surround them4 ,the vapour thus rising above the ,gulf ,stream is presently wafted by the south-westerly winds to our shores and over our whole land4 ,but as it thus reaches a region of comparative cold1 the vapour is condensed--that is1 turned into fog1 or mist1 or cloud1 according to circumstances4 ,it is during this change that it gives out the heat it has brought with it from the ,gulf ,stream4 ,for precisely as the evaporation of water is a process requiring heat1 the change of vapour into water--whether in the form of fog1 mist1 cloud1 or rain--is a process in which heat is given out4 ,thus it is that the south-westerly wind1 the commonest wind we have1 brings clouds and fogs and rain to us from the ,gulf ,stream1 and with them brings the ,gulf ,stream warmth4 ,why the south-westerly winds should be so common1 and how it is that over the ,gulf ,stream there is a sort of air-channel along which winds come to us as if by their natural pathway1 are matters inquired into farther on 7see p4 #afd74 ,the subject is full of interest1 but need not here detain us4 ,it would seem that a mechanism involving the motion of such enormous masses of water as the current-system of the ,atlantic should depend on the operation of very evident laws4 ,yet a variety of contradictory hypotheses have been put forward from time to time respecting this system of circulation1 and even now the scientific world is divided between two opposing theories4 ,of old the ,mississippi ,river was supposed to be the parent of the ,gulf ,stream4 ,it was noticed that the current flows at about the same rate as the ,mississippi1 and this fact was considered sufficient to support the strange theory that a river can give birth to an ocean-current4 ,it was easy1 however1 to overthrow this theory4 ,captain ,livingston showed that the volume of water which is poured out of the ,gulf of ,mexico in the form of an ocean stream is more than a thousand times greater than the volume poured into the ,gulf by the ,mississippi ,river4 ,having overthrown this old theory of the ,gulf ,stream1 ,captain ,livingston attempted to set up one which is equally unfounded4 ,he ascribed the current to the sun's apparent yearly motion and the influence thus exerted on the waters of the ,atlantic4 ,a sort of yearly tide is conceived1 according to this theory1 to be the true parent of the ,gulf current4 ,it need hardly be said1 however1 that a phenomenon which remains without change through the winter and summer seasons cannot possibly be referred to the operation of such a cause as a yearly tide4 ,it is to ,dr4 ,franklin that we owe the first theory of the ,gulf ,stream which has met with general acceptance4 ,he held that the ,gulf ,stream is formed by the outflow of waters which have been forced into the ,caribbean ,sea by the trade-winds2 so that the pressure of these winds on the ,atlantic ,ocean forms1 according to ,dr4 ,franklin1 the true motive power of the ,gulf ,stream machinery4 ,according to ,maury1 this theory has #8come to be the most generally received opinion in the mind of seafaring people4' ,it supplies a moving force of undoubted efficiency4 ,we know that as the trade-winds travel towards the equator they lose their westerly motion4 ,it is reasonable to suppose that this is caused by friction against the surface of the ocean1 to which1 therefore1 a corresponding westerly motion must have been imparted4 ,there is a simplicity about ,franklin's theory which commends it favourably to consideration4 ,but when we examine it somewhat more closely1 several very decided flaws present themselves to our attention4 ,consider1 in the first place1 the enormous mass of water moved by the supposed agency of the winds4 ,air has a weight--volume for volume--which is less than one eight-hundredth part of that of water4 ,so that1 to create a water-current1 an air-current more than eight hundred times as large and of equal velocity must expend the whole of its motion4 ,now the trade-winds are gentle winds1 their velocity scarcely exceeding in general that of the more swiftly-moving portions of the ,gulf ,stream4 ,but even assigning to them a velocity four times as great1 we still want an air-current two hundred times as large as the water-current4 ,and the former must give up the whole of its motion1 which1 in the case of so elastic a substance as air1 would hardly happen1 the upper air being unlikely to be much affected by the motion of the lower4 ,but this is far from being all4 ,if the trade-winds blew throughout the year1 we might be disposed to recognise their influence upon the ,gulf ,stream as a paramount1 if not the sole one4 ,but this is not the case4 ,captain ,maury states that1 #8,with the view of ascertaining the average number of days during the year that the north-east trade-winds of the ,atlantic operate upon the currents between twenty-five degrees north latitude and the equator1 log-books containing no less than #chj1bhd observations on the force and direction of the wind in that ocean were examined4 ,the data thus afforded were carefully compared and discussed4 ,the results show that within these latitudes--and on the average--the wind from the north-east is in excess of the winds from the south-west only #aaa days out of the #cfe4 ,now1 can the north-east trades1#8 he pertinently asks1 #8by blowing for less than one-third of the time1 cause the ,gulf ,stream to run all the time1 and without varying its velocity either to their force or to their prevalence8' ,and besides this1 we have to consider that no part of the ,gulf ,stream flows strictly before the trade-winds4 ,where the current flows most rapidly1 namely1 in the ,narrows of ,bemini1 it sets against the wind1 and for hundreds of miles after it enters the ,atlantic #8it runs1' says ,maury1 #8right in the 8wind's eye40#8 ,it must be remembered that a current of air directed with considerable force against the surface of still water has not the power of generating a current which can force its way far through the resisting fluid4 ,if this were so1 we might understand how the current1 originating in sub-tropical regions1 could force its way onward after the moving force had ceased to act upon it1 and even carry its waters right against the wind1 after leaving the ,gulf of ,mexico4 ,but experience is wholly opposed to this view4 ,the most energetic currents are quickly dispersed when they reach a wide expanse of still water4 ,for example1 the ,niagara below the falls is an immense and rapid river4 ,yet when it reaches ,lake ,ontario1 #8instead of preserving its character as a distinct and well-defined stream for several hundred miles1 it spreads itself out1 and its waters are immediately lost in those of the lake4' ,here1 again1 the question asked by ,maury bears pertinently on the subject we are considering4 #8,why1' he says1 #8should not the ,gulf ,stream do the same8 ,it gradually enlarges itself1 it is true2 but1 instead of mingling with the ocean by broad spreading1 as the immense rivers descending into the northern lakes do1 its waters1 like a stream of oil in the ocean1 preserve a distinctive character for more than three thousand miles4' ,the only other theory which has been considered in recent times to account satisfactorily for all the features of the ,gulf ,stream mechanism was put forward1 we believe1 by ,captain ,maury4 ,in this theory1 the motive power of the whole system of oceanic circulation is held to be the action of the sun's heat upon the waters of the sea4 ,we recognise two contrary effects as the immediate results of the sun's action4 ,in the first place1 by warming the equatorial waters1 it tends to make them lighter2 in the second place1 by causing evaporation1 it renders them salter1 and so tends to make them heavier4 ,we have to inquire which form of action is most effective4 ,the inquiry would be somewhat difficult1 if we had not the evidence of the sea itself to supply an answer4 ,for it is an inquiry to which ordinary experimental processes would not be applicable4 ,we must accept the fact that the heated water from the equatorial seas actually does float upon the cooler portions of the ,atlantic1 as evidence that the action of the sun results in making the water lighter4 ,now1 ,maury says that the water thus lightened must flow over and form a surface-current towards the ,poles2 while the cold and heavy water from the polar seas1 as soon as it reaches the temperate zone1 must sink and form a submarine current4 ,he recognises in these facts the mainspring of the whole system of oceanic circulation4 ,if a long trough be divided into two compartments1 and we fill one with oil and the other with water1 and then remove the dividing plate1 we shall see the oil rushing over the water at one end of the trough1 and the water rushing under the oil at the other4 ,and if we further conceive that oil is continually being added at that end of the trough originally filled with oil1 while water is continually added at the other1 it is clear that the system of currents would continue in action3 that is1 there would be a continual flow of oil in one direction along the surface of the water1 and of water in the contrary direction underneath the oil4 ,but ,sir ,john ,herschel maintains that no such effects as ,maury describes could follow the action of the sun's heat upon the equatorial waters4 ,he argues thus3 ,granting that these waters become lighter and expand in volume1 yet they can only move upwards1 downwards1 or sideways4 ,there can be nothing to cause either of the two first forms of motion2 and as for motion sideways1 it can only result from the gradual slope caused by the bulging of the equatorial waters4 ,he proceeds to show that this slope is so slight that we cannot look upon it as competent to form any sensible current from the equatorial towards the polar seas4 ,and even if it could1 he says1 the water thus flowing off would have an eastward instead of a westward motion1 precisely as the counter-trade-winds1 blowing from equatorial to polar regions1 have an eastward motion4 ,it is singular how completely the supporter of each rival view has succeeded in overthrowing the arguments of his opponent4 ,certainly ,maury has shown with complete success that the inconstant trade-winds cannot account for the constant ,gulf current1 which does not even flow before them1 but1 in places1 exactly against their force4 ,and the reasoning of ,sir ,john ,herschel seems equally cogent1 for certainly the flow of water from equatorial towards polar regions ought from the first to have an eastward1 instead of a westward motion2 whereas the equatorial current1 of which the ,gulf ,stream is but the continuation1 flows from east to west1 right across the ,atlantic4 ,equally strange is it to find that each of these eminent men1 having read the arguments of the other1 reasserts1 but does not effectually defend1 his own theory1 and repeats with even more damaging effect his arguments against the rival view4 ,yet one or other theory must at least point to the true view1 for the ,atlantic is subject to no other agencies which can for a moment be held to account for a phenomenon of such magnitude as the ,gulf ,stream4 ,it appears to me1 that on a close examination of the ,gulf ,stream mechanism1 the true mainspring of its motion can be recognised4 ,compelled to reject the theory that the trade-winds generate the equatorial current westward1 let us consider whether ,herschel's arguments against the #8heat theory' may not suggest a hint for our guidance4 ,he points out that an overflow from the equator polewards would result in an eastward1 and not in a westward1 current4 ,this is true4 ,it is equally true that a flow of water towards the equator would result in a westward current4 ,but no such flow is observed4 ,is it possible that there may be such a flow1 but that it takes place in a hidden manner8 ,clearly there may be4 ,submarine currents towards the equator would have precisely the kind of motion we require1 and if any cause drew them to the surface near the equator1 they would account in full for the great equatorial westward current4 ,at this point we begin to see that an important circumstance has been lost sight of in dealing with the heat theory4 ,the action of the sun on the surface-water of the equatorial ,atlantic has only been considered with reference to its warming effects4 ,but we must not forget that this action has drying effects also4 ,it evaporates enormous quantities of water1 and we have to inquire whence the water comes by which the sea-level is maintained4 ,a surface flow from the sub-tropical seas would suffice for this purpose1 but no such flow is observed4 ,whence1 then1 can the water come but from below8 ,thus we recognise the fact that a process resembling suction is continually taking place over the whole area of the equatorial ,atlantic1 the agent being the intense heat of the tropical sun4 ,no one can doubt that this agent is one of adequate power4 ,indeed1 the winds1 conceived by ,franklin to be the primary cause of the ,atlantic currents1 are in reality due to the merest fraction of the energy inherent in the sun's heat4 ,we have other evidence that the indraught is from below in the comparative coldness of the equatorial current4 ,the ,gulf ,stream is warm by comparison with the surrounding waters1 but the equatorial current is cooler than the tropical seas4 ,according to ,professor ,ansted1 the southern portion of the equatorial current1 as it flows past ,brazil1 #8is everywhere a cold current1 generally from four to six degrees below the adjacent ocean4' ,if we here recognise the mainspring of the ,gulf ,stream mechanism1 or rather of the whole system of oceanic circulation-for the movements observed in the ,atlantic have their exact counterpart in the ,pacific--we shall have no difficulty in accounting for all the motions which that mechanism exhibits4 ,we need no longer look upon the ,gulf ,stream as the rebound of the equatorial current from the shores of ,north ,america4 ,knowing that there is an underflow towards the equator1 we see that there must be a surface-flow towards the ,poles4 ,and this flow must as inevitably result in an easterly motion as the underflow towards the equator results in a westerly motion4 ,we have1 indeed1 the phenomena of the trades and counter-trades exhibited in water-currents instead of air-currents4 7,from the ,st4 ,paul's ,magazine1 ,september #ahfi47i ,,floods ,,in ,,switzerland4 ,recently 7see date of essay7 we have witnessed a succession of remarkable evidences of ,nature's destructive powers4 ,the fires of ,vesuvius1 the earth-throes of the sub-equatorial ,andes1 and the submarine disturbance which has shaken ,hawaii1 have presented to us the various forms of destructive action which the earth's1 subterranean forces can assume4 ,in the disastrous floods which have recently visited the ,alpine cantons of ,switzerland1 we have evidence of the fact that natural forces which we are in the habit of regarding as beneficent and restorative may exhibit themselves as agents of the most widespread destruction4 ,i have pointed out elsewhere 7see p4 #bbf7 how enormous is the amount of power of which the rain-cloud is the representative2 and in doing so ,i have endeavoured to exhibit the contrast between the steady action of the falling shower and the energy of the processes of which rain is in reality the equivalent4 ,but in the floods which have lately ravaged ,switzerland we see the same facts illustrated1 not by numerical calculations or by the results of philosophical experiments1 but in action1 and that action taking place on the most widely extended scale4 ,the whole of the south-eastern1 or1 as it may be termed1 the ,alpine half of ,switzerland1 has suffered from these floods4 ,if a line be drawn from the ,lake of ,constance1 in the north-east of ,switzerland1 to the ,col de ,balme1 in the south-west1 it will divide ,switzerland into two nearly equal portions1 and scarcely a canton within the eastern of these divisions has escaped without great damage4 ,the cantons which have suffered most terribly are those of ,tessin1 ,grisons1 and ,st4 ,gall4 ,the ,st4 ,gothard1 ,splugen1 and ,st4 ,bernhardin routes have been rendered impassable4 ,twenty-seven lives were lost in the ,st4 ,gothard ,pass1 besides horses and waggons full of merchandise4 ,it is stated that on the three routes upwards of eighty persons perished4 ,in the village of ,loderio alone1 no less than fifty deaths occurred4 ,so terrible a flood has not taken place since the year #ahcd4 ,nor have the cantons of ,uri and ,valais escaped4 ,from ,unterwalden we hear that the heavy rains which took place a fortnight ago have carried away several large bridges1 and many of the rivers continue still very swollen4 ,i have already described how enormous the material losses are which have been caused by these floods4 ,many places are under water2 others in ruins or absolutely destroyed4 ,in ,tessin alone the damage is estimated at forty thousand pounds sterling4 ,a country like ,switzerland must always be liable to the occurrence1 from time to time1 of catastrophes of this sort4 ,or rather1 perhaps1 we should draw a distinction between the two divisions of ,switzerland referred to above4 ,of these the one may be termed the mountain half1 and the other the lake half of the country4 ,it is the former portion of the country which is principally subject to the dynamical action of water4 ,a long-continued and heavy rainfall over the higher lands cannot fail to produce a variety of remarkable effects1 where the arrangement of mountains and passes1 hills1 valleys1 and ravines is so complicated4 ,there are places where a large volume of water can accumulate until the barriers which have opposed its passage to the plains burst under its increasing weight2 and then follow those destructive rushes of water which sweep away whole villages at once4 ,it is1 in fact1 the capacity of the ,swiss mountain region for damming up water1 far more than any other circumstance1 which renders the ,swiss floods so destructive4 ,and then it must be remembered that there are at all times suspended over the plains and valleys which lie beneath the ,alpine ranges enormous masses of water in the form of snow and ice4 ,although in general these suffer no changes but those due to the partial melting which takes place in summer1 and the renewed accumulation which takes place in winter1 yet when heavy rains fall upon the less elevated portions of the ,alpine snow1 they not only melt that snow much more rapidly than the summer sun would do1 but they wash down large masses1 which add largely to the destructive power of the descending waters4 ,the most destructive floods which have occurred in ,switzerland have usually been those which take place in early summer4 ,the floods which inundated the plains of ,martigny in #ahah were a remarkable instance of the effects which result from the natural damming up of large volumes of water in the upper parts of the ,alpine hill-country4 ,the whole of the valley of ,bagnes1 one of the largest of the lateral branches of the main valley of the ,rhone above ,geneva1 was converted into a lake1 in the spring of #ahah1 by the damming up of a narrow pass into which avalanches of snow and ice had been precipitated from a lofty glacier overhanging the bed of the river ,dranse4 ,the ice barrier enclosed a lake no less than half a league in length and an eighth of a mile wide1 and in places two hundred feet deep4 ,the inhabitants of the neighbouring villages were terrified by the danger which was to be apprehended from the bursting of the barrier4 ,they cut a gallery seven hundred feet long through the ice1 while the waters had as yet risen to but a moderate height2 and when the waters began to flow through this channel1 its course was deepened by the melting of the ice1 and at length nearly half the contents of the lake were safely carried off4 ,it was hoped that the process would continue1 and the country be saved from the danger which had been so long impending over it4 ,but as the heat of the weather increased1 the central part of the barrier slowly melted away1 until it became too weak to bear the enormous weight of water which was pressing against it4 ,at length it gave way1 so suddenly and completely that all the water which remained in the lake rushed out in half an hour4 ,the downward passage of the water illustrated1 in a very remarkable way1 the fact that the chief mischief of floods is occasioned where water is checked in its outflow4 ,for it is related that1 #8in the course of their descent the waters encountered several narrow gorges1 and at each of these they rose to a great height1 and then burst with new violence into the next basin1 sweeping along forests1 houses1 bridges1 and cultivated land4' ,along the greater part of its course the flood resembled rather a moving mass of rock and mud than a stream of water4 ,enormous masses of granite were torn out of the sides of the valleys and whirled for hundreds of yards along the course of the flood4 ,m4 ,escher relates that one of the fragments thus swept along was no less than sixty yards in circumference4 ,at first the water rushed onwards at a rate of more than a mile in three minutes1 and the whole distance 7forty-five miles7 which separates the valley of ,bagnes from the ,lake of ,geneva was traversed in little more than six hours4 ,the bodies of persons who had been drowned in ,martigny were found floating on the farther side of the lake of ,geneva1 near ,vevey4 ,thousands of trees were torn up by the roots1 and the ruins of buildings which had been overthrown by the flood were carried down beyond ,martigny4 ,in fact1 the flood at this point was so high that some of the houses in ,martigny were filled with mud up to the second storey4#8 ,beyond ,martigny the flood did but little damage1 as it here expanded over the plain1 and was reduced both in depth and velocity4 7,from the ,daily ,news for ,october #bj1 #ahfh47 ,,footnotes3 #i ,see #8,light ,science' 7second series7 for a discussion of later researches4 ,a ,,great ,,tidal ,,wave4 ,during the last few days anxious questionings have been heard respecting the next spring tides4 ,a certain naval officer1 who conceives that he can trace in the relative positions of the sun and moon the secret of every important change of weather1 has described in the columns of a contemporary the threatening significance of the approaching conjunction of the sun and moon4 ,he predicts violent atmospheric disturbances2 though in another place he tells us merely that the conjunction is to cause #8unsettled weather1' a state of matters to which we in ,england have become tolerably well accustomed4 ,but people are asking what is the actual relation which is to bring about such terrible events4 ,the matter is very simple4 ,on ,october #e1 the moon will be new--in other words1 if it were not for the brightness of the sun1 we should see the moon close by that luminary on the heavens4 ,thus the sun and moon will pull with combined effect upon the waters of the earth1 and so cause what are called spring tides4 ,this1 of course1 happens at the time of every new moon1 but sometimes the moon exerts a more effective pull than at other times2 and the same happens also in the case of the sun2 and on ,october #e1 it happens that both the sun and the moon will give a particularly vigorous haul upon the earth's waters4 ,as regards the sun1 there is nothing unusual4 ,every ,october his pull on the ocean is much the same as in preceding ,octobers4 ,but ,october is a month of high solar tides--and for these reasons3--,in ,september1 as everyone knows1 the sun crosses the equinoctial2 and1 other things being equal1 it would be when on the equinoctial that his power to raise a tidal wave would be greatest4 ,but other things are not equal2 for the sun is not always at the same distance from the earth4 ,he is nearest in ,january2 so that he would exert more power in that month than in any other1 if his force depended solely on distance4 ,as matters actually stand1 it will be obvious that at some time between ,september and ,january the sun's tidal power would have a maximum value4 ,thus it is that ,october is a month of high solar tidal waves4 ,but it is the lunar wave which will be most effectively strengthened at the next spring tide4 ,if we could watch the lunar tidal wave alone 7instead of always finding it combined with the solar wave7 we should find it gradually increasing1 and then gradually diminishing1 in a period of about a lunar month4 ,and we should find that it was always largest when the moon looked largest1 and vice vers4 ,in other words1 when the moon is in perigee the lunar wave is largest4 ,but then there is another consideration4 ,the lunar wave would vary according to the moon's proximity to the equinoctial2 and 7other things being equal7 would be largest when the moon is exactly opposite the earth's equator4 ,if the two effects are combined1 that is1 if the moon happens to be in perigee and on the equinoctial at the same time1 then of course we get the largest lunar tidal wave we can possibly have4 ,now this #8largest lunar wave' occurs at somewhat long intervals1 because the relation on which it depends is one which is1 so to speak1 exceptional4 ,still the relation does recur1 and with a certain degree of regularity4 ,when it happens1 however1 it by no means follows that we have a very high tide2 because it may occur when the tides are near #8neap'2 in other words1 when the sun and moon exert opposing effects4 ,the largest lunar wave cannot stand the drain which the solar wave exerts upon it at the time of neap tides4 ,nor would the large lunar tidal wave produce an exceptionally high tide1 even though it were not the time of #8neap1' or were tolerably near the time of #8spring' tides4 ,only when it happens that a large lunar wave combines fully with the solar wave1 do we get very high tides4 ,and when1 in addition to this relation1 we have the solar wave nearly at a maximum1 we get the highest of all possible tides4 ,this is what will happen1 or all but happen1 on ,october #e next4 ,the combination of circumstances is almost the most effective that can possibly exist4 ,but1 after all1 high tides depend very importantly on other considerations than astronomical ones4 ,most of us remember how a predicted high tide some two years ago turned out to be a very moderate1 or1 if we may use the expression1 a very #8one-horse' affair indeed1 because the winds had not been consulted1 and exerted their influence against the astronomers4 ,a long succession of winds blowing off-shore would reduce a spring tide to a height scarcely exceeding the ordinary neap4 ,on the other hand1 if we should have a long succession of westerly winds from the ,atlantic before the approaching high tide1 it is certain that a large amount of mischief may be done in some of our riverside regions4#aj ,as for the predicted weather changes1 they may be regarded as mere moonshine4 ,a number of predictions1 founded on the motions of the sun and moon1 have found a place during many months past in the columns of a contemporary2 but there has been no greater agreement between these predictions and the weather actually experienced than anyone could trace between ,old ,moore's weather prophecies and recorded weather changes4 ,in other words1 there have been certain accordances which would be very remarkable indeed if they did not happen to be associated with as many equally remarkable discordances4 ,random predictions would be quite as satisfactory4 ,a very amusing misprint has found its way into many newspapers in connection with the coming tide4 ,it is interesting as serving to show how little is really known by the general public about some of the simplest scientific matters4 ,the original statement announced that the sun would not be in perihelion by so many seconds of semi-diameter1 in itself a very incorrect mode of expression4 ,still it was clear that what was meant was1 that the earth would be so far from the place of nearest approach to the sun that the latter would not look as large as it possibly can look1 by so many seconds of semi-diameter4 ,in many papers1 however1 we read that the #8sun will not be in perihelion by so many seconds of mean chronometer6' ,who first devised this marvellous reading is unknown4 7,from the ,daily ,news for ,september #bg1 #ahfi47 ,,footnotes3 #aj ,the wave did little mischief1 the winds being easterly4 ,,deep-,,sea ,,dredgings4 ,men have ever been strangely charmed by the unknown and the seemingly inaccessible4 ,the astronomer exhibits the influence of this charm as he constructs larger and larger telescopes1 that he may penetrate more and more deeply beyond the veil which conceals the greater part of the universe from the unaided eye4 ,the geologist1 seeking to piece together the fragmentary records of the past which the earth's surface presents to him1 is equally influenced by the charm of mystery and difficulty4 ,and the microscopist who tries to force from nature the secret of the infinitely little1 is led on by the same strange desire to discover just those matters which nature has been most careful to conceal from us4 ,the energy with which in recent times men have sought to master the problem of deep-sea sounding and deep-sea dredging is1 perhaps1 one of the most striking instances ever afforded of the charm which the unknown possesses for mankind4 ,not long ago1 one of the most eminent geographers of the sea spoke regretfully about the small knowledge men have obtained of the depths of ocean4 #8,greater difficulties1' he remarked1 #8than any presented by the problem of deep-sea research have been overcome in other branches of physical inquiry4 ,astronomers have measured the volumes and weighed the masses of the most distant planets1 and increased thereby the stock of human knowledge4 ,is it creditable to the age that the depths of the sea should remain in the category of unsolved problems8 that its 8ooze and bottom0 should be a sealed volume1 rich with ancient and eloquent legends and suggestive of many an instructive lesson that might be useful and profitable to man8#8 ,since that time1 however1 deep-sea dredging has gradually become more and more thoroughly understood and mastered4 ,when the telegraphic cable which had lain so many months at the bottom of the ,atlantic was hauled on board the #8,great ,eastern' from enormous depths1 men were surprised and almost startled by the narrative4 ,the appearance of the ooze-covered cable as it was slowly raised towards the surface1 and the strange thrill which ran through those who saw it and remembered through what mysterious depths it had twice passed2 its breaking away almost from the very hands of those who sought to draw it on board2 and the successful renewal of the attempt to recover the cable1--all these things were heard of as one listens to a half-incredible tale4 ,yet when that work was accomplished deep-sea dredging had already been some time a science1 and many things had been achieved by its professors which presented1 in reality1 greater practical difficulties than the recovery of the ,atlantic ,cable4 ,recently1 however1 deep-sea researches have been carried on with results which are even more sensational1 so to speak1 than the grappling feat which so surprised us4 ,seas so deep that many of the loftiest summits of the ,alps might be completely buried beneath them have been explored4 ,dredges weighing with their load of mud nearly half a ton have been hauled up without a hitch from depths of some #ad1jjj feet4 ,but not merely has comparatively rough work of this sort been achieved1 but by a variety of ingenious contrivances men of science have been able to measure the temperature of the sea at depths where the pressure is so enormous as to be equivalent to a weight of more than #dcj tons on every square foot of surface4 ,the results of these researches are even more remarkable and surprising1 however1 than the means by which they have been obtained4 ,sir ,charles ,lyell has fairly spoken of them as so astonishing #8that they have to the geologist almost a revolutionary character4' ,let us consider a few of them4 ,no light can be supposed to penetrate to the enormous depth just spoken of4 ,therefore1 how certainly we might conclude that there can be no life there4 ,if1 instead of dealing with the habitability of planets1 ,whewell1 in his #8,plurality of ,worlds1' had been considering the question whether at depths of two or three miles living creatures could subsist1 how convincingly would he have proved the absurdity of such a supposition4 ,intense cold1 perfect darkness1 and a persistent pressure of two or three tons to the square inch1--such1 he might have argued1 are the conditions under which life exists1 if at all1 in those dismal depths4 ,and even if he had been disposed to concede the bare possibility that life of some sort may be found there1 then certainly1 he would have urged1 some new sense must replace sight--the creatures in these depths can assuredly have no eyes1 or only rudimentary ones4 ,but the recent deep-sea dredgings have proved that not only does life exist in the very deepest parts of the ,atlantic1 but that the beings which live and move and have their being beneath three miles of water have eyes which the ablest naturalists pronounce to be perfectly developed4 ,light1 then1 of some sort must exist in those abysms1 though whether the home of the deep-sea animals be phosphorescent1 as ,sir ,charles ,lyell suggests1 or whether light reaches these creatures in some other way1 we have no present means of determining4 ,if there is one theory which geologists have thought more justly founded than all others1 it is the view that the various strata of the earth were formed at different times4 ,a chalk district1 for example1 lying side by side with a sandstone district1 has been referred to a totally different era4 ,whether the chalk was formed first1 or whether the sandstone existed before the minute races came into being which formed the cretaceous stratum1 might be a question4 ,but no doubt existed in the minds of geologists that each formation belonged to a distinct period4 ,now1 however1 ,dr4 ,carpenter and ,professor ,thomson may fairly say1 #8,we have changed all this4' ,it has been found that at points of the sea-bottom only eight or ten miles apart1 there may be in progress the formation of a cretaceous deposit and of a sandstone region1 each with its own proper fauna4 #8,wherever similar conditions are found upon the dry land of the present day1' remarks ,dr4 ,carpenter1 #8it has been supposed that the formation of chalk and the formation of sandstone must have been separated from each other by long periods1 and the discovery that they may actually co-exist upon adjacent surfaces has done no less than strike at the very root of the customary assumptions with regard to geological time4'#aa ,even more interesting1 perhaps1 to many1 are the results which have been obtained respecting the varying temperatures of deep-sea regions4 ,the peculiarity just considered is1 indeed1 a consequence of such variations2 but the fact itself is at least as interesting as the consequences which flow from it4 ,it throws light on the long-standing controversy respecting the oceanic circulation4 ,it has been found that the depths of the equatorial and tropical seas are colder than those of the ,north ,atlantic4 ,in the tropics the deep-sea temperature is considerably below the freezing-point of fresh water2 in the deepest part of the ,bay of ,biscay the temperature is several degrees above the freezing-point4 ,thus one learns that the greater part of the water which lies deep below the surface of the equatorial and tropical seas comes from the ,antarctic regions1 though undoubtedly there are certain relatively narrow currents which carry the waters of the ,arctic seas to the tropics4 ,the great point to notice is that the water under the equatorial seas must really have travelled from polar regions4 ,a cold of #cj degrees can be explained in no other way4 ,we see at once1 therefore1 the explanation of those westerly equatorial currents which have been so long a subject of contest4 ,sir ,john ,herschel failed to prove that they are due to the trade winds1 but ,maury failed equally to prove that they are due to the great warmth and consequent buoyancy of the equatorial waters4 ,in fact1 while ,maury showed very convincingly that the great system of oceanic circulation is carried on despite the winds1 ,herschel proved in an equally convincing manner that the overflow conceived by ,maury should result in an easterly instead of a westerly current4 ,recently the theory was put forward that the continual process of evaporation going on in the equatorial regions leads to an indraught of cold water in bottom-currents from the polar seas4 ,such currents coming towards the equator1 that is1 travelling from latitudes where the earth's eastwardly motion is less to latitudes where that motion is greater1 would lag behind1 that is1 would have a westwardly motion4 ,it seems now placed beyond a doubt that this is the true explanation of the equatorial ocean-currents4 ,such are a few1 and but a few1 among the many interesting results which have followed from the recent researches of ,dr4 ,carpenter and ,professor ,thomson into the hitherto little-known depths of the great sea4 7,from the ,spectator1 ,december #d1 #ahfi47 ,,footnotes3 #aa ,this opinion ,dr4 ,carpenter has since somewhat modified4 ,it will be remembered1 of course1 that the evidence derived from the nature of superposed strata is in no way affected by what is shown above to hold with adjacent deposits4 ,,the ,,tunnel ,,through ,,mont ,,cenis4 ,men flash their messages across mighty continents and beneath the bosom of the wide ,atlantic2 they weigh the distant planets1 and analyse sun and stars2 they span ,niagara with a railway bridge1 and pierce the ,alps with a railway tunnel3 yet the poet of the age in which all these things are done or doing sings1 #8,we men are a puny race4' ,and certainly1 the great works which belong to man as a race can no more be held to evidence the importance of the individual man than the vast coral reefs and atolls of the ,pacific can be held to evidence the working power of the individual coral polype4 ,but if man1 standing alone1 is weak1 man working according to the law assigned to his race from the beginning--that is1 in fellowship with his kind--is verily a being of power4 ,perhaps no work ever undertaken by man strikes one as more daring than the attempt to pierce the ,alps with a tunnel4 ,nature seems to have upreared these mighty barriers as if with the design of showing man how weak he is in her presence4 ,even the armies of ,hannibal and ,napoleon seemed all but powerless in the face of these vast natural fastnesses4 ,compelled to creep slowly and cautiously along the difficult and narrow ways which alone were open to them1 decimated by the chilling blasts which swept the face of the rugged mountain-range1 and dreading at every moment the pitiless swoop of the avalanche1 the ,french and ,carthaginian troops exhibited little of the pomp and dignity which we are apt to associate with the operations of warlike armies4 ,had the denizen of some other planet been able to watch their progress1 he might indeed have said #8these men are a puny race4' ,in this only1 that they succeeded1 did the troops of ,hannibal and ,napoleon assert the dignity of the human race4 ,grand as was the aspect of nature1 and mean as was that of man during the progress of the contest1 it was nature that was conquered1 man that overcame4 ,and now man has entered on a new conflict with nature in the gloomy fastnesses of the ,alps4 ,the barrier which he had scaled of old he has now undertaken to pierce4 ,and the wwww--bold and daring as it seemed--is three parts finished4 7,see date of article47 ,the ,mont ,cenis tunnel was sanctioned by the ,sardinian ,government in #aheg1 and arrangements were made for fixing the perforating machinery in the years #aheh and #ahei4 ,but the work was not actually commenced until ,november #ahfj4 ,the tunnel--which will be fully seven and a half miles in length--was to be completed in twenty-five years4 ,the entrance to the tunnel on the side of ,france is near the little village of ,fourneau1 and lies #c1idf feet above the level of the sea4 ,the entrance on the side of ,italy is in a deep-valley at ,bardonche1 and lies #d1chj feet above the sea level4 ,thus there is a difference of level of #dcd feet4 ,but the tunnel will actually rise #dde feet above the level of the ,french end1 attaining this height at a distance of about four miles from that extremity2 in the remaining three and three-quarter miles there will be a fall of only ten feet1 so that this part of the line will be practically level4 ,the rocks through which the excavations have been made have been for the most part very difficult to work4 ,those who imagine that the great mass of our mountain ranges consists of such granite as is made use of in our buildings1 and is uniform in texture and hardness1 greatly underrate the difficulties with which the engineers of this gigantic work have had to contend4 ,a large part of the rock consists of a crystallised calcareous schist1 much broken and contorted2 and through this rock run in every direction large masses of pure quartz4 ,it will be conceived how difficult the work has been of piercing through so diversified a substance as this4 ,the perforating machines are calculated to work best when the resistance is uniform2 and it has often happened that the unequal resistance offered to the perforators has resulted in injury to the chisels4 ,but before the work of perforating began1 enormous difficulties had to be contended with4 ,it will be understood that1 in a tunnel of such vast length1 it was absolutely necessary that the perforating processes carried on from the two ends should be directed with the most perfect accuracy4 ,it has often happened in short tunnels that a want of perfect coincidence has existed between the two halves of the work1 and the tunnellers from one end have sometimes altogether failed to meet those from the other4 ,in a short tunnel this want of coincidence is not very important1 because the two interior ends of the tunnellings cannot in any case be far removed from each other4 ,but in the case of the ,mont ,cenis tunnel any inaccuracy in the direction of the two tunnellings would have been fatal to the success of the work1 since when the two ought to meet it might be found that they were laterally separated by two or three hundred yards4 ,hence it was necessary before the work began to survey the intermediate country1 so as to ascertain with the most perfect accuracy the bearings of one end of the tunnel from the other4 #8,it was necessary1' says the narrative of these initial labours1 #8to prepare accurate plans and sections for the determination of the levels1 to fix the axis of the tunnel1 and to 8set it out0 on the mountain top2 to erect observatories and guiding signals1 solid1 substantial1 and true4' ,when we remember the nature of the passes over the ,cenis1 we can conceive the difficulty of setting out a line of this sort over the ,alpine range4 ,the necessity of continually climbing over rocks1 ravines1 and precipices in passing from station to station involved difficulties which1 great as they were1 were as nothing when compared with the difficulties resulting from the bitter weather experienced on those rugged mountain heights4 ,the tempests which sweep the ,alpine passes--the ever-recurring storms of rain1 sleet1 and driving snow1 are trying to the ordinary traveller4 ,it will be understood1 therefore1 how terribly they must have interfered with the delicate processes involved in surveying4 ,it often happened that for days together no work of any sort could be done owing to the impossibility of using levels and theodolites when exposed to the stormy weather and bitter cold of these lofty passes4 ,at length1 however1 the work was completed1 and that with such success that the greatest deviation from exactitude was less than a single foot for the whole length of seven and a half miles4 ,equally remarkable and extensive were the labours connected with the preparatory works4 ,new and solid roads1 bridges1 canals1 magazines1 workshops1 forges1 furnaces1 and machinery had to be constructed2 residences had to be built for the men1 and offices for the engineers2 in fact1 at each extremity of the tunnel a complete establishment had to be formed4 ,those who have traversed ,mont ,cenis since the works began have been perplexed by the strange appearance and character of the machinery and establishments to be seen at ,modane and ,fourneau4 ,the mass of pipes and tubes1 tanks1 reservoirs1 and machinery1 which would be marvellous anywhere1 has a still stranger look in a wild and rugged ,alpine pass4 7,from the ,daily ,news1 #ahfi47 ,,tornadoes4 ,the inhabitants of the earth are subjected to agencies which--beneficial doubtless in the long run1 perhaps necessary to the very existence of terrestrial races--appear1 at first sight1 energetically destructive4 ,such are--in order of destructiveness--the hurricane1 the earthquake1 the volcano1 and the thunderstorm4 ,when we read of earthquakes such as those which overthrew ,lisbon1 ,callao1 and ,riobamba1 and learn that one hundred thousand persons fell victims in the great ,sicilian earthquake in #afic1 and probably three hundred thousand in the two earthquakes which assailed ,antioch in the years #ebf and #fab1 we are disposed to assign at once to this devastating phenomenon the foremost place among the agents of destruction4 ,but this judgment must be reversed when we consider that earthquakes--though so fearfully and suddenly destructive both to life and property--yet occur but seldom compared with wind-storms1 while the effects of a real hurricane are scarcely less destructive than those of the sharpest shocks of earthquakes4 ,after ordinary storms1 long miles of the sea-coast are strewn with the wrecks of many once gallant ships1 and with the bodies of their hapless crews4 ,in the spring of #ahff there might be seen at a single view from the heights near ,plymouth twenty-two shipwrecked vessels1 and this after a storm which1 though severe1 was but trifling compared with the hurricanes which sweep over the torrid zones1 and thence--scarcely diminished in force--as far north sometimes as our own latitudes4 ,it was in such a hurricane that the #8,royal ,charter' was wrecked1 and hundreds of stout ships with her4 ,in the great hurricane of #aghj1 which commenced at ,barbadoes and swept across the whole breadth of the ,north ,atlantic1 fifty sails were driven ashore at the ,bermudas1 two line-of-battle ships went down at sea1 and upwards of twenty thousand persons lost their lives on the land4 ,so tremendous was the force of this hurricane 7,captain ,maury tells us7 that #8the bark was blown from the trees1 and the fruits of the earth destroyed2 the very bottom and depths of the sea were uprooted--forts and castles were washed away1 and their great guns carried in the air like chaff2 houses were razed2 ships wrecked2 and the bodies of men and beasts lifted up in the air and dashed to pieces in the storm'--an account1 however1 which 7though doubtless faithfully rendered by ,maury from the authorities he consulted7 must perhaps be accepted cum grano1 and especially with reference to the great guns carried in the air #8like chaff4'#ab 7,if so1 it #8blew great guns1' indeed47 ,in the gale of ,august1 #aghb1 all the trophies of ,lord ,rodney's victory1 except the #8,ardent1' were destroyed1 two ,british ships-of-the-line foundered at sea1 numbers of merchantmen under ,admiral ,graves' convoy were wrecked1 and at sea alone three thousand lives were lost4 ,but quite recently a storm far more destructive than these swept over the ,bay of ,bengal4 ,most of my readers doubtless remember the great gale of ,october #ahfd1 in which all the ships in harbour at ,calcutta were swept from their anchorage1 and driven one upon another in inextricable confusion4 ,fearful as was the loss of life and property in ,calcutta harbour1 the destruction on land was greater4 ,a vast wave swept for miles over the surrounding country1 embankments were destroyed1 and whole villages1 with their inhabitants1 were swept away4 ,fifty thousand souls1 it is believed1 perished in this fearful hurricane4 ,the gale which has just ravaged the ,gulf of ,mexico adds another to the long list of disastrous hurricanes4 ,as ,i write1 the effects produced by this tornado are beginning to be made known4 ,already its destructiveness has become but too certainly evidenced4 ,the laws which appear to regulate the generation and the progress of cyclonic storms are well worthy of careful study4 ,the regions chiefly infested by hurricanes are the ,west ,indies1 the southern parts of the ,indian ,ocean1 the ,bay of ,bengal1 and the ,china ,seas4 ,each region has its special hurricane season4 ,in the ,west ,indies1 cyclones occur principally in ,august and ,september1 when the south-east monsoons are at their height4 ,at the same season the ,african south-westerly monsoons are blowing4 ,accordingly there are two sets of winds1 both blowing heavily and steadily from the ,atlantic1 disturbing the atmospheric equilibrium1 and thus in all probability generating the great ,west ,indian hurricanes4 ,the storms thus arising show their force first at a distance of about six or seven hundred miles from the equator1 and far to the east of the region in which they attain their greatest fury4 ,they sweep with a north-westerly course to the ,gulf of ,mexico1 pass thence northwards1 and so to the north-east1 sweeping in a wide curve 7resembling the letter placed thus 7 around the ,west ,indian seas1 and thence travelling across the ,atlantic1 generally expending their fury before they reach the shores of ,western ,europe4 ,this course is the storm-track 7or storm- as ,i shall call it74 ,of the behaviour of the winds as they traverse this track1 ,i shall have to speak when ,i come to consider the peculiarity from which these storms derive their names of #8cyclones' and tornadoes4 ,the hurricanes of the ,indian ,ocean occur at the #8changing of the monsoons4' #8,during the interregnum1#8 writes ,maury1 #8the fiends of the storm hold their terrific sway4' ,becalmed often for a day or two1 seamen hear moaning sounds in the air1 forewarning them of the coming storm4 ,then1 suddenly1 the winds break loose from the forces which have for a while controlled them1 and #8seem to rage with a fury that would break up the fountains of the deep4' ,in the ,north ,indian seas hurricanes rage at the same season as in the ,west ,indies4 ,in the ,china seas occur those fearful gales known among sailors as #8typhoons' or #8white squalls4' ,these take place at the changing of the monsoons4 ,generated1 like the ,west ,indian hurricanes1 at a distance of some ten or twelve degrees from the equator1 typhoons sweep--in a curve similar to that followed by the ,atlantic storms--around the ,east ,indian ,archipelago1 and the shores of ,china1 to the ,japanese ,islands4 ,there occur land-storms1 also1 of a cyclonic character in the valley of the ,mississippi4 #8,i have often observed the paths of such storms1' says ,maury1 #8through the forests of the ,mississippi4 ,there the track of these tornadoes is called a 8wind-road10 because they make an avenue through the wood straight along1 and as clear of trees as if the old denizens of the forest had been cleared with an axe4 ,i have seen trees three or four feet in diameter torn up by the roots1 and the top1 with its limbs1 lying next the hole whence the root came4#8 ,another writer1 who was an eye-witness to the progress of one of these ,american land-storms1 thus speaks of its destructive effects4 #8,i saw1 to my great astonishment1 that the noblest trees of the forest were falling into pieces4 ,a mass of branches1 twigs1 foliage1 and dust moved through the air1 whirled onward like a cloud of feathers1 and passing1 disclosed a wide space filled with broken trees1 naked stumps1 and heaps of shapeless ruins1 which marked the path of the tempest4' ,if it appeared1 on a careful comparison of observations made in different places1 that these winds swept directly along those tracks which they appear to follow1 a comparatively simple problem would be presented to the meteorologist4 ,but this is not found to be the case4 ,at one part of a hurricane's course the storm appears to be travelling with fearful fury along the true storm-2 at another less furiously directed across the storm-track2 at another1 but with yet diminished force1 though still fiercely1 in a direction exactly opposite to that of the storm-track4 ,all these motions appear to be fairly accounted for by the theory that the true path of the storm is a spiral--or rather1 that while the centre of disturbance continually travels onwards in a widely extended curve1 the storm-wind sweeps continually around the centre of disturbance1 as a whirlpool around its vortex4 ,and here a remarkable circumstance attracts our notice1 the consideration of which points to the mode in which cyclones may be conceived to be generated4 ,it is found1 by a careful study of different observations made upon the same storm1 that cyclones in the northern hemisphere invariably sweep round the onward travelling vortex of disturbance in one direction1 and southern cyclones in the contrary direction4 ,if we place a watch1 face upwards1 upon one of the northern cyclone regions in a ,mercator's chart1 then the motion of the hands is contrary to the direction in which the cyclone whirls2 when the watch is shifted to a southern cyclone region1 the motion of the hands is in the same direction as the cyclone motion4 ,this peculiarity is converted into the following rule-of-thumb for sailors who encounter a cyclone1 and seek to escape from the region of fiercest storm3--,facing the wind1 the centre or vortex of the storm lies to the right in the northern1 to the left in the southern hemisphere4 ,safety lies in flying from the centre in every case save one--that is1 when the sailor lies in the direct track of the advancing vortex4 ,in this case1 to fly from the centre would be to keep in the storm-track2 the proper course for the sailor when thus situated is to steer for the calmer side of the storm-track4 ,this is always the outside of the 1 as will appear from a moment's consideration of the spiral curve traced out by a cyclone4 ,thus1 if the seaman scud before the wind--in all other cases a dangerous expedient in a cyclone#ac--;he will probably escape unscathed4 ,there is1 however1 this danger1 that the storm-track may extend to or even slightly overlap the land1 in which case scudding before the gale would bring the ship upon a lee-shore4 ,and in this way many gallant ships have1 doubtless1 suffered wreck4 ,the danger of the sailor is obviously greater1 however1 when he is overtaken by the storm on the inner side of the storm-4 ,here he has to encounter the double force of the cyclonic whirl and of the advancing storm-system1 instead of the difference of the two motions1 as on the outer side of the storm-track4 ,his chance of escape will depend on his distance from the central path of the cyclone4 ,if near to this1 it is equally dangerous for him to attempt to scud to the safer side of the track1 or to beat against the wind by the shorter course1 which would lead him out of the storm- on its inner side4 ,it has been shown by ,colonel ,sir ,w4 ,reid that this is the quarter in which vessels have been most frequently lost4 ,but even the danger of this most dangerous quarter admits of degrees4 ,it is greatest where the storm is sweeping round the most curved part of its track1 which happens in about latitude twenty-five or thirty degrees4 ,in this case a ship may pass twice through the vortex of the storm4 ,here hurricanes have worked their most destructive effects4 ,and hence it is that sailors dread1 most of all1 that part of the ,atlantic near ,florida and the ,bahamas1 and the region of the ,indian ,ocean which lies south of ,bourbon and ,mauritius4 ,to show how important it is that captains should understand the theory of cyclones in both hemispheres1 we shall here relate the manner in which ,captain ,j4 ,v4 ,hall escaped from a typhoon of the ,china seas4 ,about noon1 when three days out from ,macao1 ,captain ,hall saw #8a most wild and uncommon-looking halo round the sun4' ,on the afternoon of the next day1 the barometer had commenced to fall rapidly2 and though1 as yet1 the weather was fine1 orders were at once given to prepare for a heavy gale4 ,towards evening a bank of cloud was seen in the south-east1 but when night closed the weather was still calm and the water smooth1 though the sky looked wild and a scud was coming on from the north-east4 #8,i was much interested1' says ,captain ,hall1 #8in watching for the commencement of the gale1 which ,i now felt sure was coming4 ,that bank to the south-east was the meteor 7cyclone7 approaching us1 the north-east scud1 the outer north-west portion of it2 and when at night a strong gale came on about north1 or north-north-west1 ,i felt certain we were on its western and south-western verge4 ,it rapidly increased in violence2 but ,i was pleased to see the wind veering to the north-west1 as it convinced me that ,i had put the ship on the right track--namely1 on the starboard tack1 standing1 of course1 to the south-west4 ,from ten ,a4,m4 to three ,p4,m4 it blew with great violence1 but the ship being well prepared1 rode comparatively easy4 ,the barometer was now very low1 the centre of the storm passing to the northward of us1 to which we might have been very near had we in the first place put the ship on the larboard tack4 ,but the most remarkable point of ,captain ,hall's account remains to be mentioned4 ,he had gone out of his course to avoid the storm1 but when the wind fell to a moderate gale he thought it a pity to lie so far from his proper course1 and made sail to the north-west4 #8,in less than two hours the barometer again began to fall and the storm to rage in heavy gusts4' ,he bore again to the south-east1 and the weather rapidly improved4 ,there can be little doubt that but for ,captain ,hall's knowledge of the law of cyclones1 his ship and crew would have been placed in serious jeopardy1 since in the heart of a ,chinese typhoon a ship has been known to be thrown on her beam-ends when not showing a yard of canvas4 ,if we consider the regions in which cyclones appear1 the paths they follow1 and the direction in which they whirl1 we shall be able to form an opinion as to their origin4 ,in the open ,pacific ,ocean 7as its name1 indeed1 implies7 storms are uncommon2 they are infrequent also in the ,south ,atlantic and ,south ,indian ,oceans4 ,around ,cape ,horn and the ,cape of ,good ,hope heavy storms prevail1 but they are not cyclonic1 nor are they equal in fury and frequency1 ,maury tells us1 to the true tornado4 ,along the equator1 and for several degrees on either side of it1 cyclones are also unknown4 ,if we turn to a map in which ocean-currents are laid down1 we shall see that in every #8cyclone region' there is a strongly marked current1 and that each current follows closely the track which ,i have denominated the storm-4 ,in the ,north ,atlantic we have the great ,gulf ,stream1 which sweeps from equatorial regions into the ,gulf of ,mexico1 and thence across the ,atlantic to the shores of ,western ,europe4 ,in the ,south ,indian ,ocean there is the #8south equatorial current1' which sweeps past ,mauritius and ,bourbon1 and thence returns towards the east4 ,in the ,chinese ,sea there is the north equatorial current1 which sweeps round the ,east ,indian ,archipelago1 and then merges into the ,japanese current4 ,there is also the current in the ,bay of ,bengal1 flowing through the region in which1 as we have seen1 cyclones are commonly met with4 ,there are other sea-currents besides these which yet breed no cyclones4 ,but ,i may notice two peculiarities in the currents ,i have named4 ,they all flow from equatorial to temperate regions1 and1 secondly1 they are all #8horse-shoe currents4' ,so far as ,i am aware1 there is but one other current which presents both these peculiarities--namely1 the great ,australian current between ,new ,zealand and the eastern shores of ,australia4 ,i have not yet met with any record of cyclones occurring over the ,australian current1 but heavy storms are known to prevail in that region1 and ,i believe that when these storms have been studied as closely as the storms in better-known regions1 they will be found to present the true cyclonic character4 ,now1 if we inquire why an ocean current travelling from the equator should be a #8storm-breeder1' we shall find a ready answer4 ,such a current1 carrying the warmth of intertropical regions to the temperate zones1 produces1 in the first place1 by the mere difference of temperature1 important atmospheric disturbances4 ,the difference is so great1 that ,franklin suggested the use of the thermometer in the ,north ,atlantic ,ocean as a ready means of determining the longitude1 since the position of the ,gulf ,stream at any given season is almost constant4 ,but the warmth of the stream itself is not the only cause of atmospheric disturbance4 ,over the warm water vapour is continually rising2 and1 as it rises1 is continually condensed 7like the steam from a locomotive7 by the colder air round4 #8,an observer on the moon1' says ,captain ,maury1 #8would1 on a winter's day1 be able to trace out by the mist in the air the path of the ,gulf ,stream through the sea4' ,but what must happen when vapour is condensed8 ,we know that to turn water into vapour is a process requiring--that is1 using up--a large amount of heat2 and1 conversely1 the return of vapour to the state of water sets free an equivalent quantity of heat4 ,the amount of heat thus set free over the ,gulf ,stream is thousands of times greater than that which would be generated by the whole coal supply annually raised in ,great ,britain4 ,here1 then1 we have an efficient cause for the wildest hurricanes4 ,for1 along the whole of the ,gulf ,stream1 from ,bemini to the ,grand ,banks1 there is a channel of heated--that is1 rarefied air4 ,into this channel1 the denser atmosphere on both sides is continually pouring1 with greater or less strength4 ,when a storm begins in the ,atlantic1 it always makes for this channel1 #8and1 reaching it1 turns and follows it in its course1 sometimes entirely across the ,atlantic4' #8,the southern points of ,america and ,africa have won for themselves1' says ,maury1 #8the name of 8the stormy capes10 but there is not a storm-find in the wide ocean can out-top that which rages along the ,atlantic coasts of ,north ,america4 ,the ,china seas and the ,north ,pacific may vie in the fury of their gales with this part of the ,atlantic1 but ,cape ,horn and the ,cape of ,good ,hope cannot equal them1 certainly in frequency1 nor do ,i believe1 in fury4' ,we read of a ,west ,indian storm so violent1 that #8it forced the ,gulf ,stream back to its sources1 and piled up the water to a height of thirty feet in the ,gulf of ,mexico4 ,the ship 8,ledbury ,snow0 attempted to ride out the storm4 ,when it abated she found herself high up on the dry land1 and discovered that she had let go her anchor among the tree-tops on ,elliot's ,key4#8 ,by a like reasoning1 we can account for the cyclonic storms prevailing in the ,north ,pacific ,ocean4 ,nor do the tornadoes which rage in parts of the ,united ,states present any serious difficulty4 ,the region along which these storms travel is the valley of the great ,mississippi4 ,this river at certain seasons is considerably warmer than the surrounding lands4 ,from its surface1 also1 aqueous vapour is continually being raised4 ,when the surrounding air is colder1 this vapour is presently condensed1 generating in the change a vast amount of heat4 ,we have thus a channel of rarefied air over the ,mississippi valley1 and this channel becomes a storm-track1 like the corresponding channels over the warm ocean-currents4 ,the extreme violence of land-storms is probably due to the narrowness of the track within which they are compelled to travel4 ,for it has been noticed that the fury of a sea-cyclone increases as the range of the #8whirl' diminishes1 and vice vers4 ,there seems1 however1 no special reason why cyclones should follow the storm- in one direction rather than in the other4 ,we must1 to understand this1 recall the fact that under the torrid zones the conditions necessary for the generation of storms prevail far more intensely than in temperate regions4 ,thus the probability is far greater that cyclones should be generated at the tropical than at the temperate end of the storm-4 ,still1 it is worthy of notice1 that in the land-locked ,north ,pacific ,ocean1 true typhoons have been noticed to follow the storm-track in a direction contrary to that commonly noticed4 ,the direction in which a true tornado whirls is invariably that ,i have mentioned4 ,the explanation of this peculiarity would occupy more space than ,i can here afford4 ,those readers who may wish to understand the origin of the law of cyclonic rotation should study ,herschel's interesting work on ,meteorology4 ,the suddenness with which a true tornado works destruction was strikingly exemplified in the wreck of the steamship #8,san ,francisco4' ,she was assailed by an extra-tropical tornado when about #cjj miles from ,sandy ,hook1 on ,december #bd1 #ahec4 ,in a few moments she was a complete wreck6 ,the wide range of a tornado's destructiveness is shown by this1 that ,colonel ,reid tells us of one along whose track no less than #aaj ships were wrecked1 crippled1 or dismasted4 7,from ,temple ,bar1 ,december #ahfg47 ,,footnotes3 #ab ,i remember to have read that in this hurricane guns which had long lain under water were washed up like mere drift upon the beach4 ,perhaps this circumstance grew gradually into the incredible story above recorded4 #ac ,a ship by scudding before the gale may--if the captain is not familiar with the laws of cyclones--go round and round without escaping4 ,the ship #8,charles ,heddle' did this in the ,east ,indies1 going round no less than five times4 ,,vesuvius4 ,the numerous and violent eruptions from ,mount ,vesuvius during the two last centuries seem to afford an answer to those who think there are traces of a gradually diminishing activity in the earth's internal forces4 ,that such a diminution is taking place1 we may admit2 but that its rate of progress is perceptible--that we can point to a time within the historical epoch1 nay1 even within the limits of geological evidence1 at which the earth's internal forces were certainly more active than they are at the present time--may1 ,i think1 be denied absolutely4 ,when the science of geology was but young1 and its professors sought to compress within a few years 7at the outside7 a series of events which 7we now know7 must have occupied many centuries1 there was room1 indeed1 for the supposition that modern volcanic eruptions1 as compared with ancient outbursts1 are but as the efforts of children compared with the work of giants4 ,and accordingly1 we find a distinguished ,french geologist writing1 even so late as #ahbi1 that in ancient times #8tous les phnomnes gologiques se passaient dans des dimensions centuples de celles qu'ils prsentent aujourd'hui4' ,but now we have such certain evidence of the enormous length of the intervals within which volcanic regions assumed their present appearance--we have such satisfactory means of determining which of the events occurring within those intervals were or were not contemporary--that we are safe from the error of assuming that ,nature at a single effort fashioned widely extended districts just as we now see them4 ,and accordingly1 we have the evidence of the distinguished geologist1 ,sir ,charles ,lyell1 that there is no volcanic mass #8of ancient date1 distinctly referable to a single eruption1 which can even rival in volume the matter poured out from ,skaptr ,jokul in #aghc4' ,in the volcanic region of which ,vesuvius or ,somma is the principal vent1 we have a remarkable instance of the deceptive nature of that state of rest into which some of the principal volcanoes frequently fall for many centuries together4 ,for how many centuries before the ,christian era ,vesuvius had been at rest is not known2 but this is certain1 that from the landing of the first ,greek colony in ,southern ,italy1 ,vesuvius gave no signs of internal activity4 ,it was recognised by ,strabo as a volcanic mountain1 but ,pliny did not include it in the list of active volcanoes4 ,in those days1 the mountain presented a very different appearance from that which it now exhibits4 ,in place of the two peaks now seen1 there was a single1 somewhat flattish summit1 on which a slight depression marked the place of an ancient crater4 ,the fertile slopes of the mountain were covered with well-cultivated fields1 and the thriving cities ,herculaneum1 ,pompeii1 and ,stabi stood near the base of the sleeping mountain4 ,so little did any thought of danger suggest itself in those times1 that the bands of slaves1 murderers1 and pirates which flocked to the standards of ,spartacus found a refuge1 to the number of many thousands1 within the very crater itself4 ,but though ,vesuvius was at rest1 the region of which ,vesuvius is the main vent was far from being so4 ,the island of ,pithecusa 7the modern ,ischia7 was shaken by frequent and terrible convulsions4 ,it is even related that ,prochyta 7the modern ,procida7 was rent from ,pithecusa in the course of a tremendous upheaval1 though ,pliny derives the name ,prochyta 7or #8poured forth'7 from the supposed fact of this island having been poured forth by an eruption from ,ischia4 ,far more probably1 ,prochyta was formed independently by submarine eruptions1 as the volcanic islands near ,santorin have been produced in more recent times4 ,so fierce were the eruptions from ,pithecusa1 that several ,greek colonies which attempted to settle on this island were compelled to leave it4 ,about #chj years before the ,christian era1 colonists under ,king ,hiero of ,syracuse1 who had built a fortress on ,pithecusa1 were driven away by an eruption4 ,nor were eruptions the sole cause of danger4 ,poisonous vapours1 such as are emitted by volcanic craters after eruption1 appear to have exhaled1 at times1 from extensive tracts on ,pithecusa1 and thus to have rendered the island uninhabitable4 ,still nearer to ,vesuvius lay the celebrated ,lake ,avernus4 ,the name ,avernus is said to be a corruption of the ,greek word ,aornos1 signifying #8without birds1' the poisonous exhalations from the waters of the lake destroying all birds which attempted to fly over its surface4 ,doubt has been thrown on the destructive properties assigned by the ancients to the vapours ascending from ,avernus4 ,the lake is now a healthy and agreeable neighbourhood1 frequented1 says ,humboldt1 by many kinds of birds1 which suffer no injury whatever even when they skim the very surface of the water4 ,yet there can be little doubt that ,avernus hides the outlet of an extinct volcano2 and long after this volcano had become inactive1 the lake which concealed its site #8may have deserved the appellation of 8atri janua ,ditis10 emitting1 perhaps1 gases as destructive of animal life as those suffocating vapours given out by ,lake ,quilotoa1 in ,quito1 in #agig1 by which whole herds of cattle were killed on its shores1 or as those deleterious emanations which annihilated all the cattle in the island of ,lancerote1 one of the ,canaries1 in #agcj4#8 ,while ,ischia was in full activity1 not only was ,vesuvius quiescent1 but even ,etna seemed to be gradually expiring1 so that ,seneca ranks this volcano among the number of nearly extinguished craters4 ,at a later epoch1 lian asserted that the mountain itself was sinking1 so that seamen lost sight of the summit at a less distance across the seas than of old4 ,yet within the last two hundred years there have been eruptions from ,etna rivalling1 if not surpassing1 in intensity the convulsions recorded by ancient historians4 ,i shall not here attempt to show that ,vesuvius and ,etna belong to the same volcanic system1 though there is reason not only for supposing this to be the case1 but for the belief that all the subterranean regions whose effects have been shown from time to time over the district extending from the ,canaries and ,azores1 across the whole of the ,mediterranean1 and into ,syria itself1 belong to but one great centre of internal action4 ,but it is quite certain that ,ischia and ,vesuvius are outlets from a single source4 ,while ,vesuvius was dormant1 resigning for a while its pretensions to be the principal vent of the great ,neapolitan volcanic system1 ,ischia1 we have seen1 was rent by frequent convulsions4 ,but the time was approaching when ,vesuvius was to resume its natural functions1 and with all the more energy that they had been for a while suspended4 ,in the year #fc 7after ,christ7 there occurred a violent convulsion of the earth around ,vesuvius1 during which much injury was done to neighbouring cities1 and many lives were lost4 ,from this period shocks of earthquake were felt from time to time for sixteen years4 ,these grew gradually more and more violent1 until it began to be evident that the volcanic fires were about to return to their main vent4 ,the obstruction which had so long impeded the exit of the confined matter was not1 however1 readily removed1 and it was only in ,august in the year #gi1 after numerous and violent internal throes1 that the superincumbent mass was at length hurled forth4 ,rocks and cinders1 lava1 sand1 and scori1 were propelled from the crater1 and spread many miles on every side of ,vesuvius4 ,we have an interesting account of the great eruption which followed in a letter from the younger ,pliny to the younger ,tacitus4 ,the latter had asked for an account of the death of the elder ,pliny1 who lost his life in his eagerness to obtain a near view of the dreadful phenomenon4 #8,he was at that time1' says his nephew1 #8with the fleet under his command at ,misenum4 ,on ,august #bd1 about one in the afternoon1 my mother desired him to observe a cloud of very extraordinary size and shape4 ,he had just returned from taking the benefit of the sun1 and1 after bathing himself in cold water1 and taking a slight repast1 had retired to his study4 ,he arose at once1 and went out upon a height whence he might more distinctly view this strange phenomenon4 ,it was not at this distance discernible from what mountain the cloud issued1 but it was found afterwards that it came from ,vesuvius4 ,i cannot give a more exact description of its figure than by comparing it to that of a pine-tree1 for it shot up to a great height in the form of a trunk1 which extended itself at the top into a sort of branches2 occasioned1 ,i suppose1 either by a sudden gust of air which impelled it1 whose force decreased as it advanced upwards1 or else the cloud itself1 being pressed back by its own weight1 expanded in this manner4 ,the cloud appeared sometimes bright1 at others dark and spotted1 as it was more or less impregnated with earth and cinders4' ,these extraordinary appearances attracted the curiosity of the elder ,pliny4 ,he ordered a small vessel to be prepared1 and started to seek a nearer view of the burning mountain4 ,his nephew declined to accompany him1 being engaged with his studies4 ,as ,pliny left the house1 he received a note from a lady whose house1 being at the foot of ,vesuvius1 was in imminent danger of destruction4 ,he set out1 accordingly1 with the design of rendering her assistance1 and also of assisting others1 #8for the villas stood extremely thick upon that lovely coast4' ,he ordered the galleys to be put to sea1 and steered directly to the point of danger1 so cool in the midst of the turmoil around #8as to be able to make and dictate observations upon the motions and figures of that dreadful scene4' ,as he approached ,vesuvius1 cinders1 pumice-stones1 and black fragments of burning rock1 fell on and around the ships4 #8,they were in danger1 too1 of running aground1 owing to the sudden retreat of the sea2 vast fragments1 also1 rolled down from the mountain and obstructed all the shore4' ,the pilot advising retreat1 ,pliny made the noble answer1 #8,fortune befriends the brave1' and bade him press onwards to ,stabi4 ,here he found his friend ,pomponianus in great consternation1 already prepared for embarking and waiting only for a change in the wind4 ,exhorting ,pomponianus to be of good courage1 ,pliny quietly ordered baths to be prepared2 and #8having bathed1 sat down to supper with great cheerfulness1 or at least 7which is equally heroic7 with all the appearance of it4' ,assuring his friend that the flames which appeared in several places were merely burning villages1 ,pliny presently retired to rest1 and #8being pretty fat1' says his nephew1 #8and breathing hard1 those who attended without actually heard him snore4' ,but it became necessary to awaken him1 for the court which led to his room was now almost filled with stones and ashes4 ,he got up and joined the rest of the company1 who were consulting on the propriety of leaving the house1 now shaken from side to side by frequent concussions4 ,they decided on seeking the fields for safety3 and fastening pillows on their heads1 to protect them from falling stones1 they advanced in the midst of an obscurity greater than that of the darkest night-though beyond the limits of the great cloud it was already broad day4 ,when they reached the shore1 they found the waves running too high to suffer them safely to venture to put out to sea4 ,pliny #8having drunk a draught or two of cold water1 lay down on a cloth that was spread out for him2 but at this moment the flames and sulphurous vapours dispersed the rest of the company1 and obliged him to rise4 ,assisted by two of his servants1 he got upon his feet1 but instantly fell down dead2 suffocated1 ,i suppose1' says his nephew1 #8by some gross and noxious vapour1 for he always had weak lungs and suffered from a difficulty of breathing4' ,his body was not found until the third day after his death1 when for the first time it was light enough to search for him4 ,he was found as he had fallen1 #8and looking more like a man asleep than dead4' ,but even at ,misenum there was danger1 though ,vesuvius is distant no less than fourteen miles4 ,the earth was shaken with repeated and violent shocks1 #8insomuch1' says the younger ,pliny1 #8that they threatened our complete destruction4' ,when morning came1 the light was faint and glimmering2 the buildings around seemed tottering to their fall1 and1 standing on the open ground1 the chariots which ,pliny had ordered were so agitated backwards and forwards that it was impossible to keep them steady1 even by supporting them with large stones4 ,the sea was rolled back upon itself1 and many marine animals were left dry upon the shore4 ,on the side of ,vesuvius1 a black and ominous cloud1 bursting with sulphurous vapours1 darted out long trains of fire1 resembling flashes of lightning1 but much larger4 ,presently the great cloud spread over ,misenum and the island of ,capre4 ,ashes fell around the fugitives4 ,on every side #8nothing was to be heard but the shrieks of women and children1 and the cries of men3 some were calling for their children1 others for their parents1 others for their husbands1 and only distinguishing each other by their voices3 one was lamenting his own fate1 another that of his family2 some wished to die1 that they might escape the dreadful fear of death2 but the greater part imagined that the last and eternal night was come1 which was to destroy the gods and the world together4' ,at length a light appeared1 which was not1 however1 the day1 but the forerunner of an outburst of flames4 ,these presently disappeared1 and again a thick darkness spread over the scene4 ,ashes fell heavily upon the fugitives1 so that they were in danger of being crushed and buried in the thick layer rapidly covering the whole country4 ,many hours passed before the dreadful darkness began slowly to be dissipated4 ,when at length day returned1 and the sun was seen faintly shining through the overhanging canopy of ashes1 #8every object seemed changed1 being covered over with white ashes as with a deep snow4' ,it is most remarkable that ,pliny makes no mention in his letter of the destruction of the two populous and important cities1 ,pompeii and ,herculaneum4 ,we have seen that at ,stabi a shower of ashes fell so heavily that several days before the end of the eruption the court leading to the elder ,pliny's room was beginning to be filled up2 and when the eruption ceased1 ,stabi was completely overwhelmed4 ,far more sudden1 however1 was the destruction of ,pompeii and ,herculaneum4 ,it would seem that the two cities were first shaken violently by the throes of the disturbed mountain4 ,the signs of such a catastrophe have been very commonly assigned to the earthquake which happened in #fc1 but it seems far more likely that most of them belong to the days immediately preceding the great outburst in #gi4 #8,in ,pompeii1' says ,sir ,charles ,lyell1 #8both public and private buildings bear testimony to the catastrophe4 ,the walls are rent1 and in many places traversed by fissures still open4' ,it is probable that the inhabitants were driven by these anticipatory throes to fly from the doomed towns4 ,for though ,dion ,cassius relates that #8two entire cities1 ,herculaneum and ,pompeii1 were buried under showers of ashes1 while all the people were sitting in the theatre1' yet #8the examination of the two cities enables us to prove1' says ,sir ,charles1 #8that none of the people were destroyed in the theatre1 and1 indeed1 that there were very few of the inhabitants who did not escape from both cities4 ,yet1' he adds1 #8some lives were lost1 and there was ample foundation for the tale in all its most essential particulars4' ,we may note here1 in passing1 that the account of the eruption given by ,dion ,cassius1 who wrote a century and a half after the catastrophe1 is sufficient to prove how terrible an impression had been made upon the inhabitants of ,campania1 from whose descendants he in all probability obtained the materials of his narrative4 ,he writes that1 #8during the eruption1 a multitude of men of superhuman stature1 resembling giants1 appeared1 sometimes on the mountain1 and sometimes in the environs2 that stones and smoke were thrown out1 the sun was hidden1 and then the giants seemed to rise again1 while the sounds of trumpets were heard'--with much other matter of a similar sort4 ,in the great eruption of #gi1 ,vesuvius poured forth lapilli1 sand1 cinders1 and fragments of old lava1 but no new lava flowed from the crater4 ,nor does it appear that any lava-stream was ejected during the six eruptions which took place during the following ten centuries4 ,in the year #ajcf1 for the first time1 ,vesuvius was observed to pour forth a stream of molten lava4 ,thirteen years later1 another eruption took place2 then ninety years passed without disturbance1 and after that a long pause of #afh years4 ,during this interval1 however1 the volcanic system1 of which ,vesuvius is the main but not the only vent1 had been disturbed twice4 ,for it is related that in #aaih the ,solfatara ,lake crater was in eruption3 and in #acjb1 ,ischia1 dormant for at least #a1djj years1 showed signs of new activity4 ,for more than a year earthquakes had convulsed this island from time to time1 and at length the disturbed region was relieved by the outburst of a lava-stream from a new vent on the south-east of ,ischia4 ,the lava-stream flowed right down to the sea1 a distance of two miles4 ,for two months1 this dreadful outburst continued to rage2 many houses were destroyed2 and although the inhabitants of ,ischia were not completely expelled1 as happened of old with the ,greek colonists1 yet a partial emigration took place4 ,the next eruption of ,vesuvius occurred in #acjf2 and then three centuries and a quarter passed during which only one eruption1 and that an unimportant one 7in #aejj71 took place4 #8,it was remarked1' says ,sir ,charles ,lyell1 #8that throughout this long interval of rest1 ,etna was in a state of unusual activity1 so as to lend countenance to the idea that the great ,sicilian volcano may sometimes serve as a channel of discharge to elastic fluids and lava that would otherwise rise to the vents in ,campania4' ,nor was the abnormal activity of ,etna the only sign that the quiescence of ,vesuvius was not to be looked upon as any evidence of declining energy in the volcanic system4 ,in #aech a new mountain was suddenly thrown up in the ,phlegran ,fields--a district including within its bounds ,pozzuoli1 ,lake ,avernus1 and the ,solfatara4 ,the new mountain was thrown up near the shores of the ,bay of ,bai4 ,it is #ddj feet above the level of the bay1 and its base is about a mile and a half in circumference4 ,the depth of the crater is #dba feet1 so that its bottom is only six yards above the level of the bay4 ,the spot on which the mountain was thrown up was formerly occupied by the ,lucrine ,lake2 but the outburst filled up the greater part of the lake1 leaving only a small and shallow pool4 ,the accounts which have reached us of the formation of this new mountain are not without interest4 ,falconi1 who wrote in #aech1 mentions that several earthquakes took place during the two years preceding the outburst1 and above twenty shocks on the day and night before the eruption4 #8,the eruption began on ,september #bi1 #aech4 ,it was on a ,sunday1 about one o'clock in the night1 when flames of fire were seen between the hot-baths and ,tripergola4 ,in a short time the fire increased to such a degree that it burst open the earth in this place1 and threw up a quantity of ashes and pumice-stones1 mixed with water1 which covered the whole country4 ,the next morning the poor inhabitants of ,pozzuoli quitted their habitations in terror1 covered with the muddy and black shower1 which continued the whole day in that country--flying from death1 but with death painted in their countenances4 ,some with their children in their arms1 some with sacks full of their goods2 others leading an ass1 loaded with their frightened family1 towards ,naples4444 ,the sea had retired on the side of ,bai1 abandoning a considerable tract2 and the shore appeared almost entirely dry1 from the quantity of ashes and broken pumice-stones thrown up by the eruption4#8 ,pietro ,giacomo di ,toledo gives us some account of the phenomena which preceded the eruption3 #8,that plain which lies between ,lake ,avernus1 the ,monte ,barbaro1 and the sea1 was raised a little1 and many cracks were made in it1 from some of which water issued2 at the same time the sea immediately adjoining the plain dried up about two hundred paces1 so that the fish were left on the sand1 a prey to the inhabitants of ,pozzuoli4 ,at last1 on ,september #bi1 about two o'clock in the night1 the earth opened near the lake1 and discovered a horrid mouth1 from which were furiously vomited smoke1 fire1 stones1 and mud composed of ashes1 making at the time of the opening a noise like the loudest thunder4 ,the stones which followed were by the flames converted to pumice1 and some of these were larger than an ox4 ,the stones went about as high as a cross-bow will carry1 and then fell down sometimes on the edge1 and sometimes into the mouth itself4 ,the mud was of the colour of ashes1 and at first very liquid1 then by degrees less so2 and in such quantities that in less than twelve hours1 with the help of the above-mentioned stones1 a mountain was raised of a thousand paces in height4 ,not only ,pozzuoli and the neighbouring country were full of this mud1 but the city of ,naples also2 so that many of its palaces were defaced by it4 ,this eruption lasted two nights and two days without intermission1 though not always with the same force2 the third day the eruption ceased1 and ,i went up with many people to the top of the new hill1 and saw down into its mouth1 which was a round cavity about a quarter of a mile in circumference1 in the middle of which the stones which had fallen were boiling up just as a cauldron of water boils on the fire4 ,the fourth day it began to throw up again1 and the seventh day much more1 but still with less violence than the first night4 ,at this time many persons who were on the hill were knocked down by the stones and killed1 or smothered with the smoke4' ,and now1 for nearly a century1 the whole district continued in repose4 ,nearly five centuries had passed since there had been any violent eruption of ,vesuvius itself2 and the crater seemed gradually assuming the condition of an extinct volcano4 ,the interior of the crater is described by ,bracini1 who visited ,vesuvius shortly before the eruption of #afca1 in terms that would have fairly represented its condition before the eruption of #gi3--#8,the crater was five miles in circumference1 and about a thousand paces deep2 its sides were covered with brushwood1 and at the bottom there was a plain on which cattle grazed4 ,in the woody parts1 wild boars frequently harboured4 ,in one part of the plain1 covered with ashes1 were three small pools1 one filled with hot and bitter water1 another salter than the sea1 and a third hot1 but tasteless4' ,but in ,december1 #afca1 the mountain blew away the covering of rock and cinders which supported these woods and pastures4 ,seven streams of lava poured from the crater1 causing a fearful destruction of life and property4 ,resina1 built over the site of ,herculaneum1 was entirely consumed by a raging lava-stream4 ,heavy showers of rain1 generated by the steam evolved during the eruption1 caused in their turn an amount of destruction scarcely less important than that resulting from the lava-streams4 ,for1 falling upon the cone1 and sweeping thence large masses of ashes and volcanic dust1 these showers produced destructive streams of mud1 consistent enough to merit the name of #8aqueous lava' commonly assigned to it4 ,an interval of thirty-five years passed before the next eruption4 ,but since #afff there has been a continual series of eruptions1 so that the mountain has scarcely ever been at rest for more than ten years together4 ,occasionally there have been two eruptions within a few months2 and it is well worthy of remark that1 during the three centuries which have elapsed since the formation of ,monte ,nuovo1 there has been no volcanic disturbance in any part of the ,neapolitan volcanic district save in ,vesuvius alone4 ,of old1 as ,brieslak well remarks1 there had been irregular disturbances in some part of the ,bay of ,naples once in every two hundred years3--the eruption of ,solfatara in the twelfth century1 that of ,ischia in the fourteenth1 and that of ,monte ,nuovo in the sixteenth2 but #8the eighteenth has formed an exception to the rule4' ,it seems clear that the constant series of eruptions from ,vesuvius during the past two hundred years has sufficed to relieve the volcanic district of which ,vesuvius is the principal vent4 ,of the eruptions which have disturbed ,vesuvius during the last two centuries1 those of #aggi1 #agic1 and #ahbb1 are in some respects the most remarkable4 ,sir ,william ,hamilton has given a very interesting account of the eruption of #aggi4 ,passing over those points in which this eruption resembled others1 we may note its more remarkable features4 ,sir ,william ,hamilton says1 that in this eruption molten lava was thrown up in magnificent jets to the height of at least #aj1jjj feet4 ,masses of stones and scori were to be seen propelled along by these lava jets4 ,vesuvius seemed to be surmounted by an enormous column of fire4 ,some of the jets were directed by the wind towards ,ottajano2 others fell on the cone of ,vesuvius1 on the outer circular mountain ,somma1 and on the valley between4 ,falling1 still red-hot and liquid1 they covered a district more than two miles and a half wide with a mass of fire4 ,the whole space above this district1 to the height of #aj1jjj feet1 was filled also with the falling and rising lava streams2 so that there was continually present a body of fire covering the extensive space ,i have mentioned1 and extending nearly two miles high4 ,the heat of this enormous fire-column was distinctly perceptible at a distance of at least six miles on every side4 ,the eruption of #agic presented a different aspect4 ,dr4 ,clarke tells us that millions of red-hot stones were propelled into the air to at least half the height of the cone itself2 then turning1 they fell all around in noble curves4 ,they covered nearly half the cone of ,vesuvius with fire4 ,huge masses of white smoke were vomited forth by the disturbed mountain1 and formed themselves1 at a height of many thousands of feet above the crater1 into a huge1 ever-moving canopy1 through which1 from time to time1 were hurled pitch-black jets of volcanic dust1 and dense vapours1 mixed with cascades of red-hot rocks and scori4 ,the rain which fell from the cloud-canopy was scalding hot4 ,dr4 ,clarke was able to compare the different appearances presented by the lava where it burst from the very mouth of the crater1 and lower down when it had approached the plain4 ,as it rushed forth from its imprisonment1 it streamed1 a liquid1 white1 and brilliantly pure river1 which burned for itself a smooth channel through a great arched chasm in the side of the mountain4 ,it flowed with the clearness of #8honey in regular channels1 cut finer than art can imitate1 and glowing with all the splendour of the sun4 ,sir ,william ,hamilton had conceived1' adds ,dr4 ,clarke1 #8that stones thrown upon a current of lava would produce no impression4 ,i was soon convinced of the contrary4 ,light bodies1 indeed1 of five1 ten1 and fifteen pounds' weight1 made little or no impression1 even at the source2 but bodies of sixty1 seventy1 and eighty pounds were seen to form a kind of bed on the surface of the lava1 and float away with it4 ,a stone of three hundredweight1 that had been thrown out by the crater1 lay near the source of the current of lava4 ,i raised it up on one end1 and then let it fall in upon the liquid lava1 when it gradually sank beneath the surface and disappeared4 ,if ,i wished to describe the manner in which it acted upon the lava1 ,i should say that it was like a loaf of bread thrown into a bowl of very thick honey1 which gradually involves itself in the heavy liquid and then slowly sinks to the bottom4 ,but as the lava flowed down the mountain slopes it lost its brilliant whiteness2 a crust began to form upon the surface of the still molten lava1 and this crust broke into innumerable fragments of porous matter called scori4 ,underneath this crust--across which ,dr4 ,clarke and his companions were able to pass without other injury than the singeing of their boots--the liquid lava still continued to force its way onward and downward past all obstacles4 ,on its arrival at the bottom of the mountain1 says ,dr4 ,clarke1 #8the whole current1' encumbered with huge masses of scori1 #8resembled nothing so much as a heap of unconnected cinders from an iron foundry1' #8rolling slowly along1#8 he says in another place1 #8and falling with a rattling noise over one another4' ,after the eruption described by ,dr4 ,clarke1 the great crater gradually filled up4 ,lava boiled up from below1 and small craters1 which formed themselves over the bottom and sides of the great one1 poured forth lava loaded with scori4 ,thus1 up to ,october #ahbb1 there was to be seen1 in place of a regular crateriform opening1 a rough and uneven surface1 scored by huge fissures1 whence vapour was continually being poured1 so as to form clouds above the hideous heap of ruins4 ,but the great eruption of #ahbb not only flung forth all the mass which had accumulated within the crater1 but wholly changed the appearance of the cone4 ,an immense abyss was formed1 three-quarters of a mile across1 and extending #b1jjj feet downwards into the very heart of ,vesuvius4 ,had the lips of the crater remained unchanged1 indeed1 the depth of this great gulf would have been far greater4 ,but so terrific was the force of the explosion that the whole of the upper part of the cone was carried clean away1 and the mountain reduced in height by nearly a full fifth of its original dimensions4 ,from the time of its formation the chasm gradually filled up2 so that1 when ,mr4 ,scrope saw it soon after the eruption1 its depth was reduced by more than #a1jjj feet4 ,of late1 ,vesuvius has been as busy as ever4 ,in #ahcc and #ahcd there were eruptions2 and in #ahef another great outburst took place4 ,then1 for three weeks together1 lava streamed down the mountain slopes4 ,a river of molten lava swept away the village of ,cercolo1 and ran nearly to the sea at ,ponte ,maddaloni4 ,there were then formed ten small craters within the great one4 ,but these have now united 7see date of article71 and pressure from beneath has formed a vast cone where they had been4 ,the cone has risen above the rim of the crater1 from which torrents of lava are poured forth4 ,at first the lava formed a lake of fire1 but the seething mass found an outlet1 and poured in a wide stream towards ,ottajano4 ,masses of red-hot stone and rock are hurled forth1 and a vast canopy of white vapour hangs over ,vesuvius1 forming at night1 when illuminated by the raging mass below1 a glory of resplendent flame around the summit of the mountain4 ,it may seem strange that the neighbourhood of so dangerous a mountain should be inhabited by races free to choose more peaceful districts4 ,yet1 though ,herculaneum1 ,pompeii1 and ,stabi lie buried beneath the lava and ashes thrown forth by ,vesuvius1 ,portici and ,resina1 ,torre del ,greco and ,torre dell' ,annunziata have taken their place2 and a large population1 cheerful and prosperous1 flourishes around the disturbed mountain1 and over the district of which it is the somewhat untrustworthy safety-valve4 ,it has1 indeed1 been well pointed out by ,sir ,charles ,lyell that #8the general tendency of subterranean movements1 when their effects are considered for a sufficient lapse of ages1 is eminently beneficial1 and that they constitute an essential part of that mechanism by which the integrity of the habitable surface is preserved4 ,why the working of this same machinery should be attended with so much evil1 is a mystery far beyond the reach of our philosophy1 and must probably remain so until we are permitted to investigate1 not our planet alone and its inhabitants1 but other parts of the moral and material universe with which they may be connected4 ,could our survey embrace other worlds1 and the events1 not of a few centuries only1 but of periods as indefinite as those with which geology renders us familiar1 some apparent contradictions might be reconciled1 and some difficulties would doubtless be cleared up4 ,but even then1 as our capacities are finite1 while the scheme of the universe must be infinite1 both in time and space1 it is presumptuous to suppose that all sources of doubt and perplexity would ever be removed4 ,on the contrary1 they might1 perhaps1 go on augmenting in number although our confidence in the wisdom of the plan of nature might increase at the same time2 for it has been justly said' 7by ,sir ,humphry ,davy7 #8that the greater the circle of light1 the greater the boundary of darkness by which it is surrounded4' 7,from the ,cornhill ,magazine1 ,march #ahfh47 ,,the ,,earthquake ,,in ,,peru4 ,the intelligence published last ,saturday 7see date of article7 is sufficient to prove that the great earthquake which has devastated ,peru fully equalled1 if it did not surpass1 the most terrible catastrophes which have ever befallen that country4 ,it presents1 too1 all the features which have hitherto characterised earthquakes in this neighbourhood4 ,these are well worthy of careful study1 and appear to have an important bearing on the modern theory of earthquakes4 ,it has been commonly held that the seat of disturbance in the earthquakes which have shaken the country west of the ,andes has lain always at some point or other beneath that range of mountains4 ,the fact that several large volcanoes are found in the ,cordilleras has seemed confirmatory of this view4 ,the account we have also of the great earthquake at ,riobamba in #agig1 seems only explicable by supposing that the seat of disturbance lay almost immediately beneath that city4 ,the inhabitants were flung vertically upwards into the air1 and to such a height that ,humboldt found the skeletons of many of them on the summit of the hill ,la ,culca1 on the farther side of the small river on which ,riobamba is built4 ,the ruins of many houses were also flung to the same spot4 ,here1 therefore1 was evidence of that vertical 7or1 as ,humboldt expresses it1 explosive7 force which is only to be looked for immediately above the centre of concussion4 ,yet the consideration of the evidence afforded by the news just published seems at first sight somewhat opposed to this view1 and to point rather to a seat of disturbance lying considerably to the west of the ,peruvian shores4 #8,at ,chala1' says our informant1 #8the sea receded1 and a wave rose fifty feet1 and returned1 spreading into the town1 a distance of about a thousand feet4 ,three successive times everything within range was swept away1 followed by twelve shocks of earthquake1 lasting from three seconds to two minutes4' ,the arrival of great sea-waves before the land-shocks were felt1 seems decisively to indicate that the seat of disturbance lay beneath the ocean1 and not beneath the land4 ,i am disposed to believe1 however1 that in the confusion of mind naturally resulting from the occurrence of so terrible a catastrophe1 the sequence of events may not have been very closely attended to1 for in other places the arrival of the great sea-wave is distinctly described as following the occurrence of the earth-shock4 ,at ,arica1 for example1 a considerable interval would seem to have elapsed before the terrible sea-wave1 which has always characterised ,peruvian earthquakes1 poured in upon the town4 ,the agent of the ,pacific ,steam ,navigation ,company1 whose house had been destroyed by the earth-shock1 saw the great sea-wave while he was flying towards the hills4 ,he writes3--',while passing towards the hills1 with the earth shaking1 a great cry went up to heaven4 ,the sea had retired4 ,on clearing the town1 ,i looked back and saw that the vessels were being carried irresistibly seawards4 ,in a few minutes the sea stopped1 and then arose a mighty wave fifty feet high1 and came in with a fearful rush1 carrying everything before it in terrible majesty4 ,the whole of the shipping came back1 speeding towards inevitable doom4 ,in a few minutes all was completed--every vessel was either on shore or bottom upwards4' ,this1 then1 was undoubtedly the great sea-wave1 as compared with the minor waves of disturbance which characterise all earthquakes near the shores of the ocean4 ,one remarkable feature in this terrible earthquake is the enormous range of country affected by it4 ,from ,quito southwards as far as ,iquique--or1 in other words1 for a distance considerably exceeding a full third part of the whole length of the ,south ,american ,andes--the shock was felt with the most terrible distinctness4 ,we have yet to learn how much farther to the north and south1 and how far inland on the eastern slopes of the ,andes1 the shock was experienced4 ,but there can be little doubt that the disturbed country was equal to at least a fourth of ,europe4 ,the portion of the ,andes thus disturbed seems to be distinct from the part to which the great ,chilian earthquakes belong4 ,the difference in character between the ,peruvian and ,chilian earthquakes is a singular and interesting phenomenon4 ,the difference corresponds to a feature long since pointed out by ,sir ,charles ,lyell1--the alternation1 on a grand scale1 of districts of active with those of extinct volcanoes4 ,it is said that in ,chili a year scarcely ever passes without shocks of earthquake being felt2 in certain regions1 not even a month4 ,a similar persistence of earthquake-disturbance characterises ,peru4 ,yet1 although both districts are shaken in this manner1 there seems to be distinct evidence of alternating disturbance as respects the occurrence of great earthquakes4 ,thus in #agig took place the terrible earthquake of ,riobamba4 ,then1 thirty years later1 a series of great earthquakes shook ,chili1 permanently elevating the whole line of coast to the height of several feet4 ,now1 again1 after another interval of about thirty years1 the ,andes are disturbed by a great earthquake1 and this time it is the ,peruvian ,andes which experience the shock4 ,between ,chili and ,peru there is a space upwards of five hundred miles long1 in which no volcanic action has been observed4 ,singularly enough1 this very portion of the ,andes1 to which one would imagine the ,peruvians and ,chilians would fly as to a region of safety1 is the part most thinly inhabited1 insomuch that1 as ,von ,buch observes1 it is in some places entirely deserted4 ,near ,quito the trembling of the earth is almost incessant1 according to ,m4 ,boussingault4 ,he considers that the frequency of the movement is due rather to the continual falling in of masses of rock which have been fractured in recent earthquakes1 than to the persistence of subterranean action4 ,he adds that the height of several mountains in the ,andes has diminished in modern times4 ,he refers1 doubtless1 to the ,peruvian and ,columbian ,andes1 and not to the ,chilian4 ,in the latter portion of the range there must be a continual increase of height1 since each earthquake in ,chili has produced a perceptible recession of the sea4 ,darwin1 indeed1 relates that near ,valparaiso he saw beds of seashells belonging to recent species at a height of about a quarter of a mile above the present sea-level2 and he concluded that the land had been raised to this height by a series of such small elevations as were observed to have taken place during the earthquakes of #ahbb1 #ahce1 and #ahcg4 ,that a contrary process should be going on in ,peru1 confirms the idea that a sort of undulatory or balancing motion is taking place--one long stretch of the ,cordilleras rising while another is sinking4 ,a tradition prevails among the ,indians of ,lican that the mountain called ,l',altar1 or ,cassac ,urcu--which means #8the chief'--was once the highest of the sub-equatorial ,andes1 being higher even than ,chimborazo2 but1 adds the tradition1 in the reign of ,quainia ,abomatha1 before the discovery of ,america1 a prodigious eruption took place1 which lasted no less than eight years1 and brought down the summit of the mountain4 ,m4 ,boussingault states that the fragments of trachyte which once formed the summit of this celebrated mountain are now spread over the plain4 ,at present ,cotopaxi is the loftiest volcano of the ,cordilleras1 its height being no less than #ah1heh feet4 ,no mountain has ever been the seat of such terrible and destructive eruptions as those which have burst forth from ,cotopaxi4 ,the intensity of the heat which prevails during eruption will be readily gathered from the circumstance that in ,january #ahjc the enormous bed of snow which usually covers the cone of the volcano was dissolved in a single night4 ,it would seem that the ,mexican volcanoes also belong to the same region of disturbance4 ,near the ,isthmus of ,panama the great ,cordillera of the ,andes is reduced to the height of about #hjj feet1 and beyond begins the continuation of the volcanic chain in ,central ,america and ,mexico4 ,nor are the volcanoes of the ,west ,indian or ,caribbee ,islands wholly disconnected with the region of disturbance in ,southern ,america4 ,and it is rather singular that even the earthquakes which have occurred in the valley of the ,mississippi seem to be connected with the ,west ,indian and ,south ,american volcanic region4 ,the violent earthquakes which took place at ,new ,madrid in #ahab occurred at exactly the same time as the earthquake of ,paranas1 #8so that it is possible1' says ,sir ,charles ,lyell1 #8that these two points are part of one volcanic region4' 7,from the ,daily ,news1 ,september #ah1 #ahfh47 ,,the ,,greatest ,,sea-,,wave ,,ever ,,known4 ,on ,august #ac1 #ahfh1 one of the most terrible calamities which has ever visited a people befell the unfortunate inhabitants of ,peru4 ,in that land earthquakes are nearly as common as rain-storms are with us2 and shocks by which whole cities are changed into a heap of ruins are by no means infrequent4 ,yet even in ,peru1 #8the land of earthquakes1' as ,humboldt has termed it1 no such catastrophe as that of ,august #ahfh had occurred within the memory of man4 ,it was not one city which was laid in ruins1 but a whole empire4 ,those who perished were counted by tens of thousands1 while the property destroyed by the earthquake was valued at millions of pounds sterling4 ,although so many months have passed since this terrible calamity took place1 scientific men have been busily engaged until quite recently in endeavouring to ascertain the real significance of the various events which were observed during and after the occurrence of the earthquake4 ,the geographers of ,germany have taken a special interest in interpreting the evidence afforded by this great manifestation of nature's powers4 ,two papers have been written recently on the great earthquake of ,august #ac1 #ahfh1 one by ,professor ,von ,hochstetter1 the other by ,herr ,von ,tschudi1 which present an interesting account of the various effects1 by land and by sea1 which resulted from the tremendous upheaving force to which the western flanks of the ,peruvian ,andes were subjected on that day4 ,the effects on land1 although surprising and terrible1 yet only differ in degree from those which have been observed in other earthquakes4 ,but the progress of the great sea-wave which was generated by the upheaval of the ,peruvian shores and propagated over the whole of the ,pacific ,ocean differs altogether from any earthquake-phenomena before observed4 ,other earthquakes have indeed been followed by oceanic disturbances2 but these have been accompanied by terrestrial motions1 so as to suggest the idea that they had been caused by the motion of the sea-bottom1 or of the neighbouring land4 ,in no instance has it ever before been known that a well-marked wave of enormous proportions should have been propagated over the largest ocean-tract on our globe1 by an earth-shock whose direct action was limited to a relatively small region1 and that region not situated in the centre1 but on one side of the wide area traversed by the wave4 ,i propose to give a brief sketch of the history of this enormous sea-wave4 ,in the first place1 however1 it may be well to remind the reader of a few of the more prominent features of the great shock to which this wave owed its origin4 ,it was at ,arequipa1 at the foot of the lofty volcanic mountain ,misti1 that the most terrible effects of the great earthquake were experienced4 ,within historic times ,misti has poured forth no lava-streams2 but that the volcano is not extinct is clearly shown by the fact that in #aedb an enormous mass of dust and ashes was vomited forth from its crater4 ,on ,august #ac1 #ahfh1 ,misti showed no signs of being disturbed4 ,so far as their volcanic neighbour was concerned1 the #dd1jjj inhabitants of ,arequipa had no reason to anticipate the catastrophe which presently befell them4 ,at five minutes past five an earthquake shock was experienced1 which1 though severe1 seems to have worked little mischief4 ,half a minute later1 however1 a terrible noise was heard beneath the earth2 a second shock more violent than the first was felt2 and then began the swaying motion1 gradually increasing in intensity4 ,in the course of the first minute this motion had become so violent that the inhabitants ran in terror out of their houses into the streets and squares4 ,in the next two minutes the swaying movement had so increased that the more lightly-built houses were cast to the ground1 and the flying people could scarcely keep their feet4 #8,and now1' says ,von ,tschudi1 #8there followed during two or three minutes a terrible scene4 ,the swaying motion which had hitherto prevailed changed into fierce vertical upheaval4 ,the subterranean roaring increased in the most terrifying manner3 then were heard the heart-piercing shrieks of the wretched people1 the bursting of walls1 the crashing fall of houses and churches1 while over all rolled thick clouds of a yellowish-black dust1 which1 had they been poured forth many minutes longer1 would have suffocated thousands4' ,although the shock had lasted but a few minutes1 the whole town was destroyed4 ,not one building remained uninjured1 and there were few which did not lie in shapeless heaps of ruins4 ,at ,tacna and ,arica1 the earth-shock was less severe1 but strange and terrible phenomena followed it4 ,at the former place a circumstance occurred1 the cause and nature of which yet remain a mystery4 ,about three hours after the earthquake--in other words1 at about eight o'clock in the evening--an intensely brilliant light made its appearance above the neighbouring mountains4 ,it lasted for fully half an hour1 and has been ascribed to the eruption of some as yet unknown volcano4 ,at ,arica the sea-wave produced even more destructive effects than had been caused by the earthquake4 ,about twenty minutes after the first earth-shock1 the sea was seen to retire1 as if about to leave the shores wholly dry2 but presently its waters returned with tremendous force4 ,a mighty wave1 whose length seemed immeasurable1 was seen advancing like a dark wall upon the unfortunate town1 a large part of which was overwhelmed by it4 ,two ships1 the ,peruvian corvette #8,america' and the ,united ,states #8double-ender' #8,watertree1#8 were carried nearly half a mile to the north of ,arica1 beyond the railroad which runs to ,tacna1 and there left stranded high and dry4 ,this enormous wave was considered by the ,english vice-consul at ,arica to have been fully fifty feet in height4 ,at ,chala1 three such waves swept in after the first shocks of earthquake4 ,they overflowed nearly the whole of the town1 the sea passing more than half a mile beyond its usual limits4 ,at ,islay and ,iquique similar phenomena were manifested4 ,at the former town the sea flowed in no less than five times1 and each time with greater force4 ,afterwards the motion gradually diminished1 but even an hour and a half after the commencement of this strange disturbance1 the waves still ran forty feet above the ordinary level4 ,at ,iquique1 the people beheld the inrushing wave whilst it was still a great way off4 ,a dark blue mass of water1 some fifty feet in height1 was seen sweeping in upon the town with inconceivable rapidity4 ,an island lying before the harbour was completely submerged by the great wave1 which still came rushing on1 black with the mud and slime it had swept from the sea-bottom4 ,those who witnessed its progress from the upper balconies of their houses1 and presently saw its black mass rushing close beneath their feet1 looked on their safety as a miracle4 ,many buildings were indeed washed away1 and in the low-lying parts of the town there was a terrible loss of life4 ,after passing far inland the wave slowly returned seawards1 and strangely enough1 the sea1 which elsewhere heaved and tossed for hours after the first great wave had swept over it1 here came soon to rest4 ,at ,callao a yet more singular instance was afforded of the effect which circumstances may have upon the motion of the sea after a great earthquake has disturbed it4 ,in former earthquakes ,callao has suffered terribly from the effects of the great sea-wave4 ,in fact1 on two occasions the whole town has been destroyed1 and nearly all its inhabitants have been drowned1 through the inrush of precisely such waves as flowed into the ports of ,arica and ,chala4 ,but upon this occasion the centre of subterranean disturbance must have been so situated that either the wave was diverted from ,callao1 or more probably two waves reached ,callao from different sources and at different times1 so that the two undulations partly counteracted each other4 ,certain it is that1 although the water retreated strangely from the coast near ,callao1 insomuch that a wide tract of the sea-bottom was uncovered1 there was no inrushing wave comparable with those described above4 ,the sea afterwards rose and fell in an irregular manner1 a circumstance confirming the supposition that the disturbance was caused by two distinct oscillations4 ,six hours after the occurrence of the earth-shock1 the double oscillations seem for a while to have worked themselves into unison1 for at this time three considerable waves rolled in upon the town4 ,but clearly these waves must not be compared with those which in other instances had made their appearance within half an hour of the earth-throes4 ,there is little reason to doubt that if the separate oscillations had reinforced each other earlier1 ,callao would have been completely destroyed4 ,as it was1 a considerable amount of mischief was effected2 but the motion of the sea presently became irregular again1 and so continued until the morning of ,august #adth1 when it began to ebb with some regularity4 ,but during the #adth there were occasional renewals of the irregular motion1 and several days elapsed before the regular ebb and flow of the sea were resumed4 ,such were among the phenomena presented in the region where the earthquake itself was felt4 ,it will be seen at once that within this region1 or rather along that portion of the sea-coast which falls within the central region of disturbance1 the true character of the sea-wave generated by the earthquake could not be recognised4 ,if a rock fall from a lofty cliff into a comparatively shallow sea1 the water around the place where the rock has fallen is disturbed in an irregular manner4 ,the sea seems at one place to leap up and down2 elsewhere one wave seems to beat against another1 and the sharpest eye can detect no law in the motion of the seething waters4 ,but presently1 outside the scene of disturbance1 a circular wave is seen to form1 and if the motion of this wave be watched1 it is seen to present the most striking contrast to the turmoil and confusion at its centre4 ,it sweeps onwards and outwards in a regular undulation4 ,gradually it loses its circular figure 7unless the sea-bottom happens to be unusually level71 showing that although its motion is everywhere regular1 it is not everywhere equally swift4 ,a wave of this sort1 though incomparably vaster1 swept swiftly away on every side from the scene of the great earthquake near the ,peruvian ,andes4 ,it has been calculated that the width of this wave varied from one million to five million feet1 or roughly1 from #bjj to #a1jjj miles1 while1 when in mid-,pacific1 the length of the wave1 measured along its summit in a widely-curved path from one side to another of the great ocean1 cannot have been less than #h1jjj miles4 ,we cannot tell how deep-seated was the centre of subterranean action2 but there can be no doubt it was very deep indeed1 because otherwise the shock felt in towns separated from each other by hundreds of miles could not have been so nearly contemporaneous4 ,therefore the portion of the earth's crust upheaved must have been enormous1 for the length of the region where the direct effects of the earthquake were perceived is estimated by ,professor ,von ,hochstetter at no less than #bdj miles4 ,the breadth of the region is unknown1 because on one side the slope of the ,andes and on the other the ocean concealed the motion of the earth's crust4 ,the great ocean wave swept1 as ,i have said1 in all directions around the scene of the earth-throe4 ,over a large part of its course its passage was unnoted1 because in the open sea the effects even of so vast an undulation could not be perceived4 ,a ship would slowly rise as the crest of the great wave passed under her1 and then as slowly sink again4 ,this may seem strange1 at first sight1 when it is remembered that in reality the great sea-wave we are considering swept at the rate of three or four hundred sea-miles an hour over the larger part of the ,pacific4 ,but when the true character of ocean-waves is understood1 when it is remembered that there is no transference of the water itself at this enormous rate1 but simply a transmission of motion 7precisely as when in a high wind waves sweep rapidly over a corn-field1 while yet each cornstalk remains fixed in the ground71 it will be seen that the effects of the great sea-wave could only be perceived near the shore4 ,even there1 as we shall presently see1 there was much to convey the impression that the land itself was rising and falling rather than that the deep was moved4 ,but among the hundreds of ships which were sailing upon the ,pacific when its length and breadth were traversed by the great sea-wave1 there was not one in which any unusual motion was perceived4 ,in somewhat less than three hours after the occurrence of the earthquake1 the ocean-wave inundated the port of ,coquimbo1 on the ,chilian seaboard1 some #hjj miles from ,arica4 ,an hour or so later it had reached ,constitucion1 #dej miles farther south2 and here for some three hours the sea rose and fell with strange violence4 ,farther south1 along the shore of ,chili1 even to the island of ,chiloe1 the shore-wave travelled1 though with continually diminishing force1 owing doubtless to the resistance which the irregularities of the shore opposed to its progress4 ,the northerly shore-wave seems to have been more considerable2 and a moment's study of a chart of the two ,americas will show that this circumstance is highly significant4 ,when we remember that the principal effects of the land-shock were experienced within that angle which the ,peruvian ,andes form with the long north-and-south line of the ,chilian and ,bolivian ,andes1 we see at once that1 had the centre of the subterranean action been near the scene where the most destructive effects were perceived1 no sea-wave1 or but a small one1 could have been sent towards the shores of ,north ,america4 ,the projecting shores of northern ,peru and ,ecuador could not have failed to divert the sea-wave towards the west2 and though a reflected wave might have reached ,california1 it would only have been after a considerable interval of time1 and with dimensions much less than those of the sea-wave which travelled southwards4 ,when we see that1 on the contrary1 a wave of even greater proportions travelled towards the shores of ,north ,america1 we seem forced to the conclusion that the centre of the subterranean action must have been so far to the west that the sea-wave generated by it had a free course to the shores of ,california4 ,be this as it may1 there can be no doubt that the wave which swept the shores of ,southern ,california1 rising upwards of sixty feet above the ordinary sea-level1 was absolutely the most imposing of all the indirect effects of the great earthquake4 ,when we consider that even in ,san ,pedro ,bay1 fully five thousand miles from the centre of disturbance1 a wave twice the height of an ordinary house rolled in with unspeakable violence only a few hours after the occurrence of the earth-throe1 we are most strikingly impressed with the tremendous energy of the earth's movement4 ,turning to the open ocean1 let us track the great wave on its course past the multitudinous islands which dot the surface of the great ,pacific4 ,the inhabitants of the ,sandwich ,islands1 which lie about #f1cjj miles from ,arica1 might have imagined themselves safe from any effects which could be produced by an earthquake taking place so far away from them4 ,but on the night between ,august #ac and #ad1 the sea around this island-group rose in a surprising manner1 insomuch that many thought the islands were sinking and would shortly subside altogether beneath the waves4 ,some of the smaller islands1 indeed1 were for a time completely submerged4 ,before long1 however1 the sea fell again1 and as it did so the observers #8found it impossible to resist the impression that the islands were rising bodily out of the water4' ,for no less than three days this strange oscillation of the sea continued to be experienced1 the most remarkable ebbs and floods being noticed at ,honolulu1 on the island of ,woahoo4 ,but the sea-wave swept onwards far beyond these islands4 ,at ,yokohama1 in ,japan1 more than #aj1ejj miles from ,arica1 an enormous wave poured in on ,august #ad1 but at what hour we have no satisfactory record4 ,so far as distance is concerned1 this wave affords most surprising evidence of the stupendous nature of the disturbance to which the waters of the ,pacific ,ocean had been subjected4 ,the whole circumference of the earth is but #be1jjj miles1 so that this wave had travelled over a distance considerably greater than two-fifths of the earth's circumference4 ,a distance which the swiftest of our ships could not traverse in less than five or six weeks had been swept over by this enormous undulation in the course of a few hours4 ,more complete details reach us from the ,southern ,pacific4 ,shortly before midnight the ,marquesas ,isles and the low-lying ,tuamotu group were visited by the great wave1 and some of these islands were completely submerged by it4 ,the lonely ,opara ,isle1 where the steamers which run between ,panama and ,new ,zealand have their coaling station1 was visited at about half-past eleven in the evening by a billow which swept away a portion of the coal dept4 ,afterwards great waves came rolling in at intervals of about twenty minutes1 and several days elapsed before the sea resumed its ordinary ebb and flow4 ,it was not until about half-past two on the morning of ,august #ad1 that the ,samoa ,isles 7sometimes called the ,navigator ,islands7 were visited by the great wave4 ,the watchmen startled the inhabitants from their sleep by the cry that the sea was about to overwhelm them2 and already1 when the terrified people rushed from their houses1 the sea was found to have risen far above the highest watermark4 ,but it presently began to sink again1 and then commenced a series of oscillations1 which lasted for several days and were of a very remarkable nature4 ,once in every quarter of an hour the sea rose and fell1 but it was noticed that it rose twice as rapidly as it sank4 ,this peculiarity is well worth remarking4 ,the eminent physicist ,mallet speaks thus 7,i follow ,lyell's quotation7 about the waves which traverse an open sea3 #8,the great sea-wave1 advancing at the rate of several miles in a minute1 consists1 in the deep ocean1 of a long low swell of enormous volume1 having an equal slope before and behind1 and that so gentle that it might pass under a ship without being noticed4 ,but when it reaches the edge of soundings its front slope becomes short and steep1 while its rear slope is long and gentle4' ,on the shores visited by such a wave1 the sea would appear to rise more rapidly than it sank4 ,we have seen that this happened on the shores of the ,samoan group1 and therefore the way in which the sea rose and fell on the days following the great earthquake gave significant evidence of the nature of the sea-bottom in the neighbourhood of these islands4 ,as the change of the great wave's figure could not have been quickly communicated1 we may conclude with certainty that the ,samoan ,islands are the summits of lofty mountains1 whose sloping sides extend far towards the east4 ,this conclusion affords interesting evidence of the necessity of observing even the seemingly trifling details of important phenomena4 ,the wave which visited the ,new ,zealand ,isles was altogether different in character1 affording a noteworthy illustration of another remark of ,mallet's4 ,he says that where the sea-bottom slopes in such a way that there is water of some depth close in-shore1 the great wave may roll in and do little damage2 and we have seen that so it happened in the case of the ,samoan ,islands4 ,but he adds1 that #8where the shore is shelving1 there will be first a retreat of the water1 and then the wave will break upon the beach and roll far in upon the land4' ,this is precisely what happened when the great wave reached the eastern shores of ,new ,zealand1 which are known to shelve down to very shallow water1 continuing far away to sea towards the east3-- ,at about half-past three on the morning of ,august #ad the water began to retreat in a singular manner from the ,port of ,lyttelton1 on the eastern shores of the southernmost of the ,new ,zealand ,islands4 ,at length the whole port was left entirely dry1 and so remained for about twenty minutes4 ,then the water was seen returning like a wall of foam ten or twelve feet in height1 which rushed with a tremendous noise upon the port and town4 ,towards five o'clock the water again retired1 very slowly as before1 not reaching its lowest ebb until six4 ,an hour later1 a second huge wave inundated the port4 ,four times the sea retired and returned with great power at intervals of about two hours4 ,afterwards the oscillation of the water was less considerable1 but it had not wholly ceased until ,august #ag1 and only on the #ahth did the regular ebb and flow of the tide recommence4 ,around the ,samoan group the water rose and fell once in every fifteen minutes1 while on the shores of ,new ,zealand each oscillation lasted no less than two hours4 ,doubtless the different depths of water1 the irregular conformation of the island groups1 and other like circumstances1 were principally concerned in producing these singular variations4 ,yet they do not seem fully sufficient to account for so wide a range of difference4 ,possibly a cause yet unnoticed may have had something to do with the peculiarity4 ,in waves of such enormous extent1 it would be quite impossible to determine whether the course of the wave-motion was directed full upon a line of shore or more or less obliquely4 ,it is clear that in the former case the waves would seem to follow each other more swiftly than in the latter1 even though there were no difference in their velocity4 ,far on beyond the shores of ,new ,zealand the great wave coursed1 reaching at length the coast of ,australia4 ,at dawn of ,august #ad1 ,moreton ,bay was visited by five well-marked waves4 ,at ,newcastle1 on the ,hunter ,river1 the sea rose and fell several times in a remarkable manner1 the oscillatory motion commencing at half-past six in the morning4 ,but the most significant evidence of the extent to which the sea-wave travelled in this direction was afforded at ,port ,fairy1 ,belfast1 ,south ,victoria4 ,here the oscillation of the water was distinctly perceived at midday on ,august #ad2 and yet1 to reach this point1 the sea-wave must not only have travelled on a circuitous course nearly equal in length to half the circumference of the earth1 but must have passed through ,bass's ,straits1 between ,australia and ,van ,diemen's ,land1 and so have lost a considerable portion of its force and dimensions4 ,when we remember that had not the effects of the earth-shock been limited by the shores of ,south ,america1 a wave of disturbance equal in extent to that which travelled westward would have swept towards the east1 we see that the force of the shock was sufficient to have disturbed the waters of an ocean covering the whole surface of the earth4 ,for the sea-waves which reached ,yokohama in one direction and ,port ,fairy in another had each traversed a distance nearly equal to half the earth's circumference2 so that if the surface of the earth were all sea1 waves setting out in opposite directions from the centre of disturbance would have met each other at the antipodes of their starting-point4 ,it is impossible to contemplate the effects which followed the great earthquake--the passage of a sea-wave of enormous volume over fully one-third of the earth's surface1 and the force with which1 at the farthermost limits of its range1 the wave rolled in upon shores more than #aj1jjj miles from its starting-place--without feeling that those geologists are right who deny that the subterranean forces of the earth are diminishing in intensity4 ,it may be difficult1 perhaps1 to look on the effects which are ascribed to ancient earth-throes without imagining for a while that the power of modern earthquakes is altogether less4 ,but when we consider fairly the share which time had in those ancient processes of change1 when we see that while mountain ranges were being upheaved or valleys depressed to their present position1 race after race and type after type appeared on the earth1 and lived out the long lives which belong to races and to types1 we are recalled to the remembrance of the great work which the earth's subterranean forces are still engaged upon4 ,even now continents are being slowly depressed or upheaved1 even now mountain ranges are being raised to a new level1 table-lands are in process of formation1 and great valleys are being gradually scooped out4 ,it may need an occasional outburst such as the earthquake of ,august #ahfh to remind us that great forces are at work beneath the earth's surface4 ,but1 in reality1 the signs of change have long been noted4 ,old shore-lines shift their place1 old soundings vary2 the sea advances in one place and retires in another2 on every side ,nature's plastic hand is at work modelling and remodelling the earth1 in order that it may always be a fit abode for those who are to dwell upon it4 7,from ,fraser's ,magazine1 ,july #ahgj47 ,,the ,,usefulness ,,of ,,earthquakes4 ,we have lately had fearful evidence of the energy of the earth's internal forces4 ,a vibration which1 when considered with reference to the dimensions of the earth's globe1 may be spoken of as an indefinitely minute quivering limited to an insignificant area1 has sufficed to destroy the cities and villages of whole provinces1 to cause the death of thousands of human beings1 and to effect a destruction of property which must be estimated by millions of pounds sterling4 ,such a catastrophe as this serves indeed to show how poor and weak a creature man is in presence of the grand workings of ,nature4 ,the mere throes which accompany her unseen subterranean efforts suffice to crumble man's strongest buildings in a moment into dust1 while the unfortunate inhabitants are either crushed to death among the ruins1 or forced to remain shuddering spectators of the destruction of their homes4 ,at first sight it may seem paradoxical to assert that earthquakes1 fearfully destructive as they have so often proved1 are yet essentially preservative and restorative phenomena2 yet this is strictly the case4 ,had no earthquakes taken place in old times1 man would not now be living on the face of the earth2 if no earthquakes were to take place in future1 the term of man's existence would be limited within a range of time far less than that to which it seems likely1 in all probability1 to be extended4 ,if the solid substance of the earth formed a perfect sphere in ante-geologic times--that is1 in ages preceding those to which our present geologic studies extend--there can be no doubt that there was then no visible land above the surface of the water2 the ocean must have formed a uniformly deep covering to the submerged surface of the solid globe4 ,in this state of things1 nothing but the earth's subterranean forces could tend to the production of continents and islands4 ,let me be understood4 ,i am not referring to the possibility or impossibility that lands and seas should suddenly have assumed their present figure without convulsion of any sort2 this might have happened1 since the ,creator of all things can doubtless modify all things according to ,his will2 ,i merely say that1 assuming that in the beginning1 as now1 ,he permitted all things to work according to the laws ,he has appointed1 then1 undoubtedly1 the submerged earth must have risen above the sea by the action of those very forms of force which produce the earthquake in our own times4 ,however this may be1 it is quite certain that when once continents and lands had been formed1 there immediately began a struggle between destructive and restorative 7rather1 perhaps1 than preservative7 forces4 ,the great enemy of the land is water1 and water works the destruction of the land in two principal ways4 ,in the first place the sea tends to destroy the land by beating on its shores1 and thus continually washing it away4 ,it may seem at first sight that this process must necessarily be a slow one2 in fact1 many may be disposed to say that it is certainly a slow process1 since we see that it does not alter the forms of continents and islands perceptibly in long intervals of time4 ,but1 as a matter of fact1 we have never had an opportunity of estimating the full effects of this cause1 since its action is continually being checked by the restorative forces we shall presently have to consider4 ,were it not thus checked1 there can be little doubt that its effects would be cumulative2 for the longer the process continued--that is1 the more the land was beaten away--the higher would the sea rise1 and the greater power would it have to effect the destruction of the remaining land4 ,i proceed to give a few instances of the sea's power of effecting the rapid destruction of the land when nothing happens to interfere with the local action--premising1 that this effect is altogether insignificant in comparison with that which would take place1 even in that particular spot1 if the sea's action were everywhere left unchecked4 ,the ,shetland ,isles are composed of substances which seem1 of all others1 best fitted to resist the disintegrating forces of the sea--namely1 granite1 gneiss1 mica-slate1 serpentine1 greenstone1 and many other forms of rock3 yet1 exposed as these islands are to the uncontrolled violence of the ,atlantic ,ocean1 they are undergoing a process of destruction which1 even within historical times1 has produced very noteworthy changes4 #8,steep cliffs are hollowed out1' says ,sir ,charles ,lyell1 #8into deep caves and lofty arches2 and almost every promontory ends in a cluster of rocks imitating the forms of columns1 pinnacles1 and obelisks4' ,speaking of one of the islands of this group1 ,dr4 ,hibbert says3 #8,the isle of ,stennes presents a scene of unequalled desolation4 ,in stormy winters1 large blocks of stone are overturned1 or are removed from their native beds1 and hurried to a distance almost incredible4 ,in the winter of #ahjb1 a tabular mass1 eight feet two inches by seven feet1 and five feet one inch thick1 was dislodged from its bed1 and carried to a distance of from eighty to ninety feet4 ,in other parts of the ,shetland ,isles1 where the sea has encountered less solid materials1 the work of destruction has proceeded yet more effectively4 ,in ,roeness1 for example1 the sea has wrought its way so fiercely that a large cavernous aperture #bej feet long has been hollowed out4 ,but the most sublime scene1' says ,dr4 ,hibbert1 #8is where a mural pile of porphyry1 escaping the process of disintegration that is devastating the coast1 appears to have been left as a sort of rampart against the inroads of the ocean4 ,the ,atlantic1 when provoked by wintry gales1 batters against it with all the force of real artillery2 and the waves1 in their repeated assaults1 have at length forced for themselves an entrance4 ,this breach1 named the ,grind of the ,navir1 is widened every winter by the overwhelming surge that1 finding a passage through it1 separates large stones from its sides1 and forces them to a distance of no less than #ahj feet4 ,in two or three spots1 the fragments which have been detached are brought together in immense heaps1 that appear as an accumulation of cubical masses1 the product of some quarry4' ,let us next turn to a portion of the coast-line of ,great ,britain which is neither defended1 on the one hand1 by barriers of rock1 nor attacked1 on the other1 by the full fury of the ,atlantic currents4 ,along the whole coast of ,yorkshire we find evidences of a continual process of dilapidation4 ,between the projecting headland of ,flamborough and ,spurn ,point 7the coast of ,holderness7 the waste is particularly rapid4 ,many spots1 which are now mere sandbanks1 are marked in the old maps of ,yorkshire as the sites of ancient towns and villages4 ,speaking of ,hyde 7one of these71 ,pennant says3 #8,only the tradition is left of this town4' ,owthorne and its church have been for the most part destroyed1 as also ,auburn1 ,hartburn1 and ,kilnsea4 ,mr4 ,phillips1 in his #8,geology of ,yorkshire1' states that not unreasonable fears are entertained that1 at some future time1 ,spurn ,point itself will become an island1 or be wholly washed away1 and then the ocean1 entering into the estuary of the ,humber1 will cause great devastation4 ,pennant states that #8several places1 once towns of note upon the ,humber1 are now only recorded in history2 and ,ravensperg was at one time a rival of ,hull1 and a port so very considerable in #accb1 that ,edward ,baliol and the confederate ,english barons sailed from hence to invade ,scotland2 and ,henry ,,iv41 in #acii1 made choice of this port to land at1 to effect the deposal of ,richard ,,ii42 yet the whole of this has since been devoured by the merciless ocean2 extensive sands1 dry at low water1 are to be seen in their stead4' ,the same writer also describes ,spurn ,point as shaped like a sickle1 and the land to the north1 he says1 was #8perpetually preyed on by the fury of the ,german ,sea1 which devours whole acres at a time4' ,the decay of the shores of ,norfolk and ,suffolk is also remarkably rapid4 ,sir ,charles ,lyell relates some facts which throw an interesting light on the ravages which the sea commits upon the land here4 ,it was computed that when a certain inn was built at ,sherringham1 seventy years would pass before the sea could reach the spot3 #8the mean loss of land being calculated from previous observations to be somewhat less than one yard annually4' ,but no allowance had been made for the fact that the ground sloped from the sea4 ,in consequence of this peculiarity1 the waste became greater and greater every year as the cliff grew lower4 #8,between the years #ahbd and #ahbi1 no less than seventeen yards were swept away2' and when ,sir ,charles ,lyell saw the place1 only a small garden was left between the building and the sea4 ,i need hardly add that all vestiges of the inn have long since disappeared4 ,lyell also relates that1 in #ahbi1 there was a depth of water sufficient to float a frigate at a point where1 less than half a century before1 there stood a cliff fifty feet high with houses upon it4 ,i have selected these portions of the coast of ,great ,britain1 not because the destruction of our shores is greater here than elsewhere1 but as serving to illustrate processes of waste and demolition which are going on around all the shores1 not merely of ,great ,britain1 but of every country on the face of the earth4 ,here and there1 as ,i have said1 there are instances in which a contrary process seems to be in action4 ,low-lying banks and shoals are formed--sometimes along stretches of coast extending for a considerable distance4 ,but when we consider these formations closely1 we find that they rather afford evidence of the energy of the destructive forces to which the land is subject than promise to make up for the land which has been swept away4 ,in the first place1 every part of these banks consists of the debris of other coasts4 ,now we cannot doubt that of earth which is washed away from our shores1 by far the larger part finds its way to the bottom of the deep seas2 a small proportion only can be brought 7by some peculiarity in the distribution of ocean-currents1 or in the progress of the tidal wave7 to aid in the formation of shoals and banks4 ,the larger1 therefore1 such shoals and banks may be1 the larger must be the amount of land which has been washed away never to reappear4 ,and although banks and shoals of this sort grow year by year larger and larger1 yet 7unless added to artificially7 they continue always either beneath the surface of the water in the case of shoals1 or but very slightly raised above the surface4 ,now1 if we suppose the destruction of land to proceed unchecked1 it is manifest that at some period1 however remote1 the formation of shoals and banks must come to an end1 owing to the continual diminution of the land from the demolition of which they derive their substance4 ,in the meantime1 the bed of the sea would be continually filling up1 the level of the sea would be continually rising1 and thus the banks would be either wholly submerged through the effect of this cause alone1 or they would have so slight an elevation above the sea-level that they would offer little resistance to the destructive effects of the sea1 which would then have no other land to act upon4 ,but we have yet to consider the second principal cause of the wasting away of the land4 ,the cause we have just been dealing with acts upon the shores or outlines of islands and continents2 the one we have now to consider acts upon their interior4 ,many1 perhaps1 would hardly suppose that the fall of rain upon the land could have any appreciable influence in the demolition of continents2 but1 as a matter of fact1 there are few causes to which geologists attribute more importance4 ,the very fact that enormous deltas have been formed at the mouths of many rivers--in other words1 the actual growth of continents through the effects of rainfall--is a proof how largely this cause must tend to destroy and disintegrate the interiors of our continents4 ,dwelling on this point1 ,sir ,charles ,lyell presents the following remarkable illustration3 #8,during a tour in ,spain1' he writes1 #8,i was surprised to see a district of gently undulating ground in ,catalonia1 consisting of red and grey sandstone1 and in some parts of red marl1 almost entirely denuded of herbage2 while the roots of the pines1 holm oaks1 and some other trees1 were half exposed1 as if the soil had been washed away by a flood4 ,such is the state of the forests1 for example1 between ,oristo and ,vich1 and near ,san ,lorenzo4 ,but being overtaken by a violent thunderstorm in the month of ,august1 ,i saw the whole surface1 even the highest levels of some flat-topped hills1 streaming with mud1 while on every declivity the devastation of torrents was terrific4 ,the peculiarities in the physiognomy of the district were at once explained2 and ,i was taught that1 in speculating on the greater effects which the direct action of rain may once have produced on the surface of certain parts of ,england1 we need not revert to periods when the heat of the climate was tropical4' ,combining the effects of the sea's action upon the shores of continents1 and of the action of rain upon their interior1 and remembering that unless the process of demolition were checked in some way1 each cause would act from year to year with new force--one through the effects of the gradual rise of the sea-bed1 and the other through the effects of the gradual increase of the surface of ocean exposed to the vaporising action of the sun1 which increase would necessarily increase the quantity of rain yearly precipitated on the land--we see the justice of the opinion expressed by ,sir ,john ,herschel1 that1 #8had the primeval world been constructed as it now exists1 time enough has elapsed1 and force enough directed to that end has been in activity1 to have long ago destroyed every vestige of land4' ,we see1 then1 the necessity that exists for the action of some restorative or preservative force sufficient to counteract the effects of the continuous processes of destruction indicated above4 ,if we consider1 we shall see that the destructive forces owe their efficiency to their levelling action1 that is1 to their influence in reducing the solid part of the earth to the figure of a perfect sphere2 therefore the form of force which is required to counteract them is one that shall tend to produce irregularities in the surface-contour of the earth4 ,and it will be remarked1 that although upheaval is the process which appears at first sight to be the only effectual remedy to the levelling action of rains and ocean-currents1 yet the forcible depression of the earth's surface may prove in many instances yet more effective1 since it may serve to reduce the sea-level in other places4 ,now1 the earth's subterranean forces serve to produce the very effects which are required in order to counteract the continual disintegration of the shores and interior parts of continents4 ,in the first place1 their action is not distributed with any approach to uniformity over different parts of the earth's crust1 and therefore the figure they tend to give to the surface of that crust is not that of a perfect sphere4 ,this1 of itself1 secures the uprising of some parts of the solid earth above the sea-level4 ,but this is not all4 ,on a comparison of the various effects due to the action of subterranean forces1 it has been found that the forces of upheaval act 7on the whole7 more powerfully under continents1 and especially under the shore-lines of continents1 while the forces of depression act most powerfully 7on the whole7 under the bed of the ocean4 ,it need hardly be said that whenever the earth is upheaved in one part1 it must be depressed somewhere else4 ,not necessarily at the same instant1 it should be remarked4 ,the process of upheaval may be either momentarily accompanied by a corresponding process of depression1 or the latter process may take place by a gradual action of the elastic powers of the earth's crust2 but1 in one way or the other1 the balance between upheaval and depression must be restored4 ,hence1 if it can be shown that for the most part the forces of upheaval act underneath the land1 it follows--though we may not be able to recognise the fact by obvious visible signs--that processes of depression are taking place underneath the ocean4 ,now1 active volcanoes mark the centre of a district of upheaval1 and most volcanoes are near the sea1 as if 7though1 of course1 this is not the true explanation7 ,nature had provided against the inroads of the ocean by seating the earth's upheaving forces just where they are most wanted4 ,even in earthquake districts which have no active vent1 the same law is found to prevail4 ,it is supposed by the most eminent seismologists that earthquake regions around a volcano1 and earthquake regions apparently disconnected from any outlet1 differ only in this respect1 that in the one case the subterranean forces have had sufficient power to produce the phenomena of eruption1 while in the other they have not4 #8,in earthquakes1' says ,humboldt1 #8we have evidence of a volcano-producing force2 but such a force1 as universally diffused as the internal heat of the globe1 and proclaiming itself everywhere1 rarely acts with sufficient energy to produce actual eruptive phenomena2 and when it does so1 it is only in isolated and particular places4' ,of the influence of the earth's subterranean forces in altering the level of land1 ,i might quote many remarkable instances1 but considerations of space compel me to confine myself to two or three4 ,the slow processes of upheaval or depression may1 perhaps1 seem less immediately referable to subterranean action than those which are produced during the progress of an actual earthquake4 ,i pass over1 therefore1 such phenomena as the gradual uprising of ,sweden1 the slow sinking of ,greenland1 and 7still proceeding westward7 the gradual uprising of ,nova ,scotia and the shores of ,hudson's ,bay4 ,remarkable and suggestive as these phenomena really are1 and indisputable as the evidence is on which they rest1 they will probably seem much less striking to the reader than those which ,i am now about to quote4 ,on the #aith of ,november1 #ahbb1 a widely felt and destructive earthquake was experienced in ,chili4 ,on the next day1 it was noticed for the first time that a broad line of sea-coast had been deserted by the sea for more than one hundred miles4 ,a large part of this tract was covered by shell-fish1 which soon died1 and exhaled the most offensive effluvia4 ,between the old low-water mark and the new one1 the fishermen found burrowing shells1 which they had formerly had to search for amidst the surf4 ,rocks some way out to sea which had formerly been covered1 were now dry at half ebb-tide4 ,careful measurements showed that the rise of the land was greater at some distance inshore than along the beach4 ,the watercourse of a mill about a mile inland from the sea had gained a fall of fourteen inches in little more than a hundred yards4 ,at ,valparaiso1 the rise was three feet2 at ,quintero1 four feet4 ,in ,february #ahce1 and in ,november #ahcg1 a large tract of ,chili was similarly shaken1 a permanent rise of two feet following the former earthquake1 and a rise of eight feet the latter4 ,the earthquake which took place at ,cutch in #ahai is perhaps in some respects yet more remarkable4 ,in this instance1 phenomena of subsidence1 as well as phenomena of upheaval1 were witnessed4 ,the estuary of the ,indus1 which had long been closed to navigation--being1 in fact1 only a foot deep at ebb-tide1 and never more than six feet at flood--was deepened in parts to more than eighteen feet at low water4 ,the fort and village of ,sindree were submerged1 only the tops of houses and walls being visible above the water4 ,but although this earthquake seemed thus to have a land-destroying1 instead of a land-creating effect1 yet the instances of upheaval were1 even in this case1 far more remarkable than those of depression4 #8,immediately after the shock1' says ,sir ,charles ,lyell1 #8the inhabitants of ,sindree saw at a distance of five miles and a half from their village a long elevated mound1 where previously there had been a low and perfectly level plain4 ,to this uplifted tract they gave the name of ,ulla-,bund1 or the 8,mound of ,god10 to distinguish it from several artificial dams previously thrown across the eastern arm of the ,indus4 ,it has been ascertained1' he adds1 #8that this new-raised country is upwards of fifty miles in length from east to west1 running parallel to the line of subsidence which caused the grounds around ,sindree to be flooded4 ,the breadth of the elevation is conjectured to be in some parts sixteen miles1 and its greatest ascertained height above the original level of the delta is ten feet--an elevation which appears to the eye to be very uniform throughout4#8 7,from ,chambers's ,journal1 ,november #g1 #ahfh47 ,,the ,,forcing ,,power ,,of ,,rain4 ,there is an old proverb which implies that ,england need never fear drought2 and we have had clear evidence this year 7#ahfh7 that an exceptionally dry summer is not necessarily followed by a bad harvest4 ,but ,i believe that when a balance is carefully struck between the good and the evil effects resulting from excessive drought in ,england1 it will be found that the latter largely prevail4 ,in fact1 it is only necessary to observe the effects which have followed the recent wet weather to recognise the fact that rain has a forcing power1 the very diminished supply of which at the due season cannot fail to have seriously injurious effects4 ,in various parts of ,england we see evidences of the action of such a power during the present autumn in the blossoming of trees1 in the flowering of primroses and other spring plants1 in rich growths of fungi1 and in various other ways4 ,it cannot be doubted that there is here a comparative waste of powers which1 expended in due season1 would have produced valuable results4 ,the modern theories of the correlation of force suffice to show how enormous a loss a country suffers when there is a failure in the supply of rain1 or when that supply comes out of its due season4 ,when we consider rain in connection with the causes to which it is due1 we begin to recognise the enormous amount of power of which the ordinary rainfall of a country is the representative2 and we can well understand how it is that #8the clouds drop fatness on the earth4' ,the sun's heat is1 of course1 the main agent--we may almost say the only agent--in supplying the rainfall of a country4 ,the process of evaporation carried on over large portions of the ocean's surface is continually storing up enormous masses of water in the form of invisible aqueous vapour1 ready to be transformed into cloud1 then wafted for hundreds of miles across seas and continents1 to be finally precipitated over this or that country1 according to the conditions which determine the downfall of rain4 ,these processes do not appear1 at first sight1 indicative of any very great expenditure of force1 yet in reality the force-equivalent of the rain-supply of ,england alone for a single year is something positively startling4 ,it has been calculated that the amount of heat required to evaporate a quantity of water which would cover an area of #ajj square miles to a depth of one inch would be equal to the heat which would be produced by the combustion of half a million tons of coals4 ,the amount of force of which this consumption of heat would be the equivalent corresponds to that which would be required to raise a weight of upwards of one thousand millions of tons to a height of one mile4 ,now1 when we remember that the area of ,great ,britain and ,ireland is about #abj1jjj square miles1 and that the annual rainfall averages about #be inches1 we see that the force-equivalent of the rainfall is enormous4 ,all the coal which could be raised from our ,english coal mines in hundreds of years would not give out heat enough to produce ,england's rain-supply for a single year4 ,when to this consideration we add the circumstance that the force of rain produces bad as well as good effects--the former when the rain falls at undue seasons or in an irregular manner1 the latter only when the rainfall is distributed in the usual manner among the seasons--we see that an important loss accrues to a country in such exceptional years as the present4 ,there are few subjects more interesting than those depending on the correlation of physical forces2 and we may add that there are few the study of which bears more largely on questions of agricultural and commercial economy4 ,it is only of late years that the silent forces of nature--forces continually in action1 but which are too apt to pass unnoticed and unrecognised--have taken their due place in scientific inquiry4 ,strangely enough1 the subject has been found to have at once a most practical bearing on business relations1 and an aspect more strikingly poetical than any other subject1 perhaps1 which men of science have ever taken in hand to investigate4 ,we see the ordinary processes of ,nature1 as they are termed1 taking their place in the workshop of modern wealth1 and at the same time exhibited in a hundred striking and interesting physical relations4 ,what1 for instance1 can be stranger or more poetical than the contrast which ,professor ,tyndall has instituted between that old friend of the agriculturist--the wintry snow-flake--and the wild scenery of the ,alps8 #8,i have seen1' he says1 #8the wild stone-avalanches of the ,alps1 which smoke and thunder down the declivities with a vehemence almost sufficient to stun the observer4 ,i have also seen snow-flakes descending so softly as not to hurt the fragile spangles of which they were composed2 yet to produce from aqueous vapour a quantity which a child could carry of that tender material demands an exertion of energy competent to gather up the shattered blocks of the largest stone-avalanche ,i have ever seen1 and pitch them to twice the height from which they fell4' ,i may point out in this place the important connection which exists between the rainfall of a country and the amount of forest land4 ,i notice that in parts of ,america attention is being paid--with markedly good results--to the influence of forests in encouraging rainfall4 ,we have here an instance in which cause and effect are interchangeable4 ,rain encourages the growth of an abundant vegetation1 and abundant vegetation in turn tends to produce a state of the superincumbent atmosphere which encourages the precipitation of rain4 ,the consequence is1 that it is very necessary to check1 before it is too late1 the processes which lead to the gradual destruction of forests4 ,if these processes are continued until the climate has become excessively dry1 it is almost impossible to remedy the mischief1 simply because the want of moisture is destructive to the trees which may be planted to encourage rainfall4 ,thus there are few processes more difficult 7as has been found by experience in parts of ,spain and elsewhere7 than the change of an arid region into a vegetation-covered district4 ,in fact1 if the region is one of great extent1 the attempt to effect such a change is a perfectly hopeless one4 ,on the other hand1 the contrary process--that is1 the attempt to change a climate which is too moist into one of less humidity--is in general not attended with much difficulty4 ,a judicious system of clearing nearly always leads to the desired result4 ,the dryness of the past year has not been due to the want of moisture in the air1 nor to the exceptionally unclouded condition of our skies4 ,i believe that1 on the whole1 the skies have been rather more cloudy than usual this year4 ,the fact that so little dew has fallen is a sufficient proof that the nights have been on the whole more cloudy than usual1 since1 as is well known1 the presence of clouds1 by checking the radiation of the earth's heat1 prevents 7or at least diminishes7 the formation of dew4 ,the fact would seem to be that the westerly and south-westerly winds which usually blow over ,england during a considerable part of the year1 bringing with them large quantities of aqueous vapour from above the great ,gulf ,stream1 have this year blown somewhat higher than usual4 ,why this should be it is not very easy to say4 ,the height of the vapour-laden winds is usually supposed to depend on the heat of the weather4 ,in summer1 for instance1 the clouds range higher1 and therefore travel farther inland before they fall in rain4 ,in winter1 on the contrary1 they travel low1 and hence the rain falls more freely in the western than in the eastern counties during winter4 ,a similar relation prevails in the ,scandinavian peninsula--,norway receiving more rain in winter than in summer1 while ,sweden receives more rain in summer than in winter4 ,but this summer the rain-clouds have blown so much higher than usual as to pass beyond ,england altogether4 ,possibly we may find an explanation in the fact that before reaching our shores at all the clouds were relieved by heavy rainfalls--probably due to some exceptional electrical relations--over parts of the ,atlantic ,ocean4 ,it is stated that the steam-ships from ,america this summer were1 in many instances1 drenched by heavy showers until they neared the coasts of ,england4 7,from the ,daily ,news1 ,october #e1 #ahfh47 ,a ,,shower ,,of ,,snow-,,crystals4 ,yesterday morning a remarkably fine fall of snow-stars took place over many parts of ,london4 ,the crystals were larger and more perfectly formed than is commonly the case in our latitudes1 where the conditions requisite for the formation of these beautiful objects are less perfectly fulfilled than in more northerly regions4 ,many forms were to be noticed which the researches of ,scoresby1 ,glaisher1 and ,lowe have shown to be somewhat uncommon4 ,some of my readers will perhaps be surprised to learn that no less than #a1jjj different kinds of snow-crystals have been noticed by the observers named above1 and that a large proportion of them have been figured and described4 ,the patterns are of wonderful beauty4 ,a strange circumstance connected with these objects is the fact that for the most part they are found1 on a close examination1 to be formed of minute coloured crystals--some red1 some green1 others blue or purple4 ,in fact1 all the colours of the rainbow are to be seen in the delicate tracery of these fine hexagonal stars4 ,so that in the perfect whiteness of the driven snow we have an illustration of the well-known fact that the colours of the rainbow combine to form the purest white4 ,for the common snow-flake is formed of a large number of such tiny crystals as were falling yesterday2 though their beauty is destroyed in the snow-flake1 through the effects of collision and partial melting4 ,it may not be very commonly known that ordinary ice1 also1 is composed of a combination of crystals presenting all the regularity of formation seen in the snow-crystals4 ,this would scarcely be believed by anyone who examined a rough mass of ice taken from the surface of a frozen lake4 ,yet1 if a slice be cut from the mass and placed in the sun's light1 or before a fire1 the beautiful phenomena called ice-flowers make their appearance4 #8,a fairy seems to have breathed upon the ice1 and caused transparent flowers of exquisite beauty suddenly to blossom in myriads within it4' ,when we remember that the enormous icebergs of the ,arctic and ,antarctic seas1 the snow-caps which crown the ,alps and ,andes and ,himalayas1 and the glaciers which urge their way with resistless force down the mountain valleys1 are all made up of these delicate and beautiful snow-flowers1 we are struck with the force of the strange contrasts which ,nature presents to our contemplation4 ,we may say of the snow-crystals what ,tennyson said of the small sea-shell4 ,each snow-star is ,frail1 but a work divine ,made so fairily well1 ,so exquisitely minute1 ,a miracle of design4 ,yet--massed together with all the prodigality of ,nature's unsparing hand--they crown the everlasting hills2 or1 falling in avalanche and glacier1 overwhelm the stoutest works of man2 or1 in vast islands of floating ice1 show themselves to be ,of force to withstand1 year upon year1 the shock ,of cataract seas that snap the three-decker's oaken spine4 7,from the ,daily ,news1 ,march #aa1 #ahfi47 ,,long ,,shots4 ,our artillerists have paid more attention of late years to the destructive properties of various forms of cannon than to the question of range4 ,it was different when first the rifling of cannon was under discussion4 ,then the subject which was most attentively considered 7after accuracy of fire7 was the range which might possibly be attained by various improvements in the structure of rifled cannon4 ,many of my readers will remember how1 soon after the construction of ,armstrong guns had been commenced in the ,government factories1 a story was spread abroad of the wonderful practice which had been made with this gun at a range of seven miles4 ,at that tremendous range1 a shot had been fired into the middle of a flock of geese1 according to one version of the story2 but this was presently improved upon1 and we were told that a bird had been singled out of the flock by the artillerists and successfully #8potted4' ,many believed this little narrative2 though some few1 influenced perhaps by the consideration that a flock of geese would not be visible at a distance of seven miles1 were obstinately incredulous4 ,presently it turned out that the ,armstrong gun was incapable of throwing a shot to a distance of seven miles2 so that a certain air of improbability has since attached to the narrative4 ,still there were not wanting those who referred to #8,queen ,anne's pocket-pistol'--the cannon which was able to throw shot across the ,straits of ,dover2 and in the fulness of their faith in that mythical piece of ordnance1 they refused to believe that the skill of modern artillerists was unequal to the construction of cannon even more effective4 ,if there are any who still believe in the powers ascribed to the far-famed #8pocket-pistol1' they will find their confidence in modern artillery largely shaken by the announcement that it is considered a great matter that one of ,whitworth's cannon should have thrown a shot to a distance of very nearly six miles and a half4 ,not only is this so1 however1 but it is well known that no piece of ordnance has ever flung a projectile to so great a distance since first fire-arms were invented2 and it may be safely predicted that men will never be able to construct a cannon which--as far as range is concerned--will do much better than this one of ,mr4 ,whitworth's4 ,the greatest range which had ever before been attained fell somewhat short of six miles4 ,the #g-;inch steel gun contrived by ,mr4 ,lynall ,thomas had flung a projectile weighing #age lbs4 to a distance of #aj1jge yards2 and1 according to ,general ,lefroy's #8,handbook of ,artillery1' that was the greatest range ever recorded4 ,but ,mr4 ,whitworth's cannon has thrown a shot more than #a1jjj yards farther4 ,very few have any idea of the difficulties which oppose themselves to the attainment of a great range in artillery practice4 ,it may seem1 at first sight1 the simplest possible matter to obtain an increase of range4 ,let the gun be made but strong enough to bear a sufficient charge1 and range seems to be merely a question of the quantity of powder made use of4 ,but in reality the matter is much more complicated4 ,the artillerist has to contrive that the whole of the powder made use of shall be burned before the shot leaves the cannon1 and yet that the charge shall not explode so rapidly as to burst the cannon4 ,if he used some forms of powder1 very useful for special purposes1 half the charge would be blown out without doing its share of work4 ,on the other hand1 there are some combustibles 7as gun-cotton and the nitrates7 which burn so fast that the gun would be likely to burst before the shot could be expelled4 ,then1 again1 the shot must fit so closely that there shall be no windage1 and yet not so closely as to resist too much the action of the exploding powder4 ,again1 there is the form of the shot to be considered4 ,a sphere is not the solid which passes most readily through a resisting medium like the air2 and yet1 other projectiles1 which are best so long as they maintain a certain position1 meet with a greater resistance when once they begin to move unsteadily4 ,the conoid used in ordinary rifle practice1 for example1 passes much more freely through the air1 point first1 than an ordinary spherical bullet2 but if the point did not travel first1 as would happen but for the rifling1 or even if the conoidal bullet #8swayed about' on its course1 it would meet with more resistance than a spherical bullet4 ,hence the question of #8fast or slow rifling' has to be considered4 #8,fast rifling' gives the greater spin1 but causes more resistance to the exit of the shot from the barrel2 with #8slow-rifling1' these conditions are reversed4 ,and then the common notion is that a cannon-ball travels in the curve called a parabola1 and that artillerists have nothing to do but to calculate all about this parabola1 and to deduce the range from the initial velocity according to some simple principles depending on the properties of the curve4 ,all this is founded on a complete misapprehension of the true difficulties in the way of the problem4 ,only projectiles thrown with small velocity from the earth travel in parabolic paths4 ,a cannon-ball follows a wholly different kind of curve4 ,the resistance of the air1 which seems to most persons a wholly insignificant item in the inquiry1 is so enormous in the case of a cannon-ball as to become by far the most important difficulty in the way of the practical artillerist4 ,when a #bej-lb4 shot is hurled with such force from a gun as to cover a range of six miles1 the resistance of the air is about forty times the weight of the ball--that is1 is equivalent to a weight of upwards of four tons4 ,the range in such a case as this is but a small fraction of that which would be given by the ordinary parabolic theory4 ,as regards artillery practice in war1 there are other difficulties in the attainment of a very extended range4 ,cannon meant for battering down forts cannot possibly be used in the same way that ,whitworth's was used at ,shoeburyness4 ,if the shot flung from this gun at an elevation of thirty-three degrees could have been watched1 it would have been found that it fell to the earth at a much greater angle--that is1 much more nearly in a perpendicular direction4 ,on the ordinary parabolic theory1 of course1 the angle of fall would be the same as the angle of elevation1 but under actual circumstances there is an important difference4 ,if forts are to be battered down1 however1 it will not serve that they should be struck from above2 our artillerists must perforce keep to the old method of pounding away at the face of the forts they attack4 ,therefore1 an elevation which is all very well for mortars--that is1 when the question merely is of flinging a bomb into a town or fortress--is utterly unsuited for ordinary artillery4 ,with an elevation of ten degrees1 ,whitworth's cannon scarcely projected the #bej-lb4 shot to a distance of three miles4 ,the progress of the modern science of gunnery certainly tends to increase the distance at which armies will engage each other4 ,with field artillery flinging shot to a distance of two or three miles1 and riflemen able to make tolerably sure practice at a distance of three-quarters of a mile1 we are not likely often to hear of hand-to-hand conflicts in future warfare4 ,the use of breech-loaders will also tend to the same effect4 ,hitherto we have scarcely had experience of the results which these changes are to produce on modern warfare4 ,at ,sadowa breech-loaders did not encounter breech-loaders1 and it was easy for the victors in that battle to come to close quarters with their enemies4 ,but in a battle where both sides are armed with breech-loaders1 we shall probably see another sort of affair altogether4 ,the bayonet will be an almost useless addition to the soldier's arms2 a charge of cavalry upon well-armed infantry will be almost as hopeless as the famous ,balaclava charge2 and the artillery on either side will have to play a game at long bowls4 ,i venture to anticipate that the first great ,european war will introduce a total change into the whole system of warlike manuvres4#ad 7,from the ,daily ,news1 ,november #ahfh47 ,,influence ,,of ,,marriage ,,on ,,the ,,death-,,rate4 ,the ,royal ,commission on the ,law of ,marriage has attracted attention to many singular and instructive results of modern statistical inquiry4 ,not the least important of these is the apparent influence of marriage on the death-rate4 ,for several years it has been noticed by statisticians that the death-rate of unmarried men is considerably higher than the death-rate of married men and widowers4 ,i believe that ,dr4 ,stark1 ,registrar-,general for ,scotland1 was one of the first to call attention to this peculiarity1 as evidenced by the results of two years' returns for ,scotland4 ,but the law has since been confirmed by a far wider range of statistical inquiry4 ,the relative proportion between the death-rates of the married and of the unmarried is not absolutely uniform in different countries1 but it is fairly enough represented by the following table1 which exhibits the mortality per thousand of married and unmarried men in ,scotland3-- ,ages4 ,husbands and ,widowers4 ,unmarried4 #bj to #be #fbf #abca #be to #hj #hbc #adid #cj to #ce #hfe #aeid #ce to #dj #aafg #afjb #dj to #de #adjg #ahce #de to #ej #agjd #baah #ej to #ee #aied #bfcd #ee to #fj #bfad #bhed #fj to #fe #cefc #dded #fe to #gj #ebic #fjba #gj to #ge #haef #ajbga #ge to #hj #aaghe #adcid #hj to #he #agchh #aiedj ,from this table we are to understand that out of one hundred thousand married persons 7including widowers7 from #bj to #be years old1 #fbf die in the course of each year2 while out of a similar number of unmarried persons1 between the same ages1 no less than #a1bca die in each year4 ,and in like manner all the other lines of the table are to be interpreted4 ,commenting on the evidence supplied by the above figures1 ,dr4 ,stark stated that #8bachelorhood is more destructive to life than the most unwholesome trades1 or than residence in an unwholesome house or district1 where there has never been the most distant attempt at sanitary improvement of any kind4' ,and this view has been very generally accepted1 not only by the public1 but by professed statisticians4 ,yet1 as a matter of fact1 ,i believe that no such inferences can legitimately be drawn from the above table4 ,dr4 ,stark appears to me to have fallen into the mistake1 which ,m4 ,quetelet tells us is so common1 of trying to make his statistics carry more weight than they are capable of bearing4 ,it is important that the matter should be put in a just light1 for the ,royal ,commission on the ,law of ,marriage has revealed no more striking fact than that of the prevalence of immature marriages1 and such reasoning as ,dr4 ,stark's certainly cannot tend to discourage these unwise alliances4 ,if death strikes down in five years only half as many of those who are married as of those who are unmarried between the ages of #bj and #be 7as appears from the above table71 and if the proportion of deaths between the two classes goes on continually diminishing in each successive lustre 7as is also shown by the above table71 it seems reasonable to infer that the death-rate would be even more strikingly disproportionate for persons between the ages of fifteen and twenty than for persons between the ages of twenty and twenty-five4 ,i believe1 indeed1 that if ,dr4 ,stark had extended his table to include the former ages1 the result would have been such as ,i have indicated4 ,yet few will suppose that very youthful marriages can exercise so singularly beneficial an effect4 ,to many ,dr4 ,stark's conclusion may appear to be a natural and obvious sequitur from the evidence upon which it is founded4 ,admitting the facts--and ,i see no reason for doubting them--it may appear at first sight that we are bound to accept the conclusion that matrimony is favourable to longevity4 ,yet the consideration of a few parallel cases will suffice to show how small a foundation the figures ,i have quoted supply for such a conclusion4 ,what would be thought1 for example1 of any of the following inferences8--,among hot-house plants there is observed a greater variety and brilliance of colour than among those which are kept in the open air2 therefore the housing of plants conduces to the splendour of their colouring4 ,or again3 ,the average height of ,life ,guardsmen is greater than that of the rest of the male population2 therefore to be a ,life ,guardsman conduces to tallness of stature4 ,or to take an example still more closely illustrative of ,dr4 ,stark's reasoning3 ,the average longevity of noblemen exceeds that of untitled persons2 therefore to have a title is conducive to longevity2 or borrowing his words1 to remain without a title #8is more destructive to life than the most unwholesome trades1 or than residence in an unwholesome house or district1 where there has never been the most distant attempt at sanitary improvement of any kind4' ,we know that the inference is absurd in each of the above instances1 and we are able at once to show where the flaw in the reasoning lies4 ,we know that splendid flowers are more commonly selected for housing1 and that ,life ,guardsmen are chosen for their tallness1 so that we are prevented from falling into the mistake of ascribing splendour of colour in the one instance1 or tallness in the other1 to the influence of causes which have nothing whatever to do with those attributes2 nor is anyone likely to ascribe the longevity of our nobility to the possession of a title4 ,yet there is nothing in any one of the above inferences which is in reality more unsound than ,dr4 ,stark's inference from the mortality bills1 when the latter are considered with due reference to the principles of interpretation which statisticians are bound to follow4 ,the fact is1 that in dealing with statistics the utmost care is required in order that our inferences may not be pushed beyond the evidence afforded by our facts4 ,in the present instance1 we have simply to deal with the fact that the death-rate of unmarried men is higher than the death-rate of married men and widowers4 ,from this fact we cannot reason as ,dr4 ,stark has done to a simple conclusion4 ,all that we can do is to show that one of three conclusions must be adopted3--,either matrimony is favourable 7directly or indirectly7 to longevity1 in a degree sufficient wholly to account for the observed peculiarity2 or a principle of selection--the effect of which is such as1 on the whole1 to fill the ranks of married men from among the healthier and stronger portion of the community--operates in a sufficient degree to account wholly for the observed death-rates2 or lastly1 the observed death-rates are due to the combination1 in some unknown proportion1 of the two causes just mentioned4 ,no reasonable doubt can exist1 as it seems to me1 that the third is the true conclusion to be drawn from the evidence supplied by the mortality bills4 ,unfortunately1 the conclusion thus deduced is almost valueless1 because we are left wholly in doubt as to the proportion which subsists between the effects to be ascribed to the two causes thus shown to be in operation4 ,it scarcely required the evidence of statistics to prove that each cause must operate to some extent4 ,it is perfectly obvious1 on the one hand1 that although hundreds of men who would be held by insurance companies to be #8bad lives' may contract marriage1 yet on the whole a principle of selection is in operation which must tend to bring the healthier portion of the male community into the ranks of the married1 and to leave the unhealthier in the state of bachelorhood4 ,a little consideration will show also that1 on the whole1 the members of the less healthy trades1 very poor persons1 habitual drunkards1 and others whose prospects of long life are unfavourable1 must 7on the average of a large number7 be more likely to remain unmarried than those more favourably situated4 ,another fact drawn from the ,registrar-,general's return suffices to prove the influence of poverty on the marriage-rate4 ,i refer to the fact that marriages are invariably more numerous in seasons of prosperity than at other times4 ,improvident marriages are undoubtedly numerous1 but prosperity and adversity have their influence1 and that influence not unimportant1 on the marriage returns4 ,on the other hand1 it is perfectly obvious that the life of a married man is likely to be more favourable to longevity than that of a bachelor4 ,the mere fact that a man has a wife and family depending upon him will suffice to render him more careful of his health1 less ready to undertake dangerous employments1 and so on2 and there are other reasons which will occur to everyone for considering the life of a married man better 7in the sense of the insurance companies7 than that of a bachelor4 ,in fact1 while we are compelled to reject ,dr4 ,stark's statement that #8bachelorhood is more destructive to life than the most unwholesome trades1 or than residence in an unwholesome house or district1 where there has never been the most distant attempt at sanitary improvement of any kind1' we may safely accept his opinion that statistics #8prove the truth of one of the first natural laws revealed to man--8,it is not good that man should live alone40' 7,from the ,daily ,news1 ,october #ag1 #ahfh47 ,,footnotes3 #ad ,the reader need hardly be reminded of the complete fulfilment of this anticipation1 during the war between ,france and ,germany4 ,,the ,,topographical ,,survey ,,of ,,india4 ,at the close of the war with ,tippoo ,sahib1 ,major ,lambton planned the triangulation of the country lying between ,madras and the ,malabar coast1 a district which had been roughly surveyed1 during the progress of the war1 by ,colonel ,mackenzie4 ,the ,duke of ,wellington gave his approval to the project1 and his brother1 the ,governor-,general of ,india1 and ,lord ,clive 7son of the great ,clive71 ,governor of ,madras1 used their influence to aid ,major ,lambton in carrying out his design4 ,the only astronomical instrument made use of by the first survey party was one of ,ramsden's zenith-sectors1 which ,lord ,macartney had placed in the hands of ,dinwiddie1 the astronomer1 for sale4 ,a steel chain1 which had been sent with ,lord ,macartney's embassy to the ,emperor of ,china and refused1 was the only apparatus available for measuring4 ,thus began the great ,trigonometrical ,survey of ,india1 a work whose importance it is hardly possible to over-estimate4 ,conducted successively by ,colonel ,lambton1 ,sir ,george ,everest1 ,sir ,andrew ,waugh1 and ,lieut4-,col4 ,walker 7the present superintendent71 the trigonometrical survey has been prosecuted with a skill and accuracy which renders it fairly comparable with the best work of ,european surveyors4 ,but to complete in this style the survey of the whole of ,india would be the work of several centuries4 ,the trigonometrical survey of ,great ,britain and ,ireland has been already more than a century in progress1 and is still unfinished4 ,it can1 therefore1 be imagined that the survey of ,india--nearly ten times the size of the ,british ,isles1 and presenting difficulties a hundredfold greater than those which the surveyor in ,england has to encounter--is not a work which can be quickly completed4 ,but the growing demands of the public service have rendered it imperatively necessary that ,india should be rapidly and completely surveyed4 ,this necessity led to the commencement of the ,topographical ,survey of ,india1 a work which has been pushed forward at a surprising rate during the past few years4 ,my readers may form some idea of the energy with which the survey is in progress1 from the fact that ,colonel ,thuillier's ,report for the season #ahff-fg announces the charting of an area half as large as ,scotland1 and the preparatory triangulation of an additional area nearly half as large as ,england4 ,in a period of thirty years1 with but few surveying parties at first1 and a slow increase in their number1 an area of #afj1jjj square miles has been completed and mapped by the topographical department4 ,the revenue surveyors have also supplied good maps 7on a similar scale7 of #cfd1jjj square miles of country during the twenty years ending in #ahff4 ,combining these results1 we have an area of #ebd1jjj square miles1 or upwards of four times that of ,great ,britain and ,ireland4 ,for all this enormous area the surveyors have the records in a methodical and systematic form1 fit for incorporation in the atlas of ,india4 ,nor does this estimate include the older revenue surveys of the ,north-western ,provinces which1 for want of proper supervision in former years1 were never regularly reduced4 ,the records of these surveys were destroyed in the ,mutiny--chiefly in ,hazaumbaugh and the south-western frontier ,agency4 ,the whole of these districts remain to be gone over in a style very superior to that of the last survey4 ,the extent of the country which has been charted may lead to the impression that the survey is little more than a hasty reconnaissance4 ,this1 however1 is very far indeed from being the case4 ,the preliminary triangulation1 which is the basis of the topographical survey1 is conducted with extreme care4 ,in the present ,report1 for instance1 we find that the discrepancies between the common sides of the triangles-in other words1 the discrepancies between the results obtained by different observers-are in some cases less than one-tenth of an inch per mile2 in others they are from one inch to a foot per mile2 and in the survey of the ,cossyah and ,garrow ,hills1 where observations had to be taken to large objects1 such as trees1 rocks1 c41 with no defined points for guidance1 the results differ by as much as twenty-six inches per mile4 ,these discrepancies must not only be regarded as insignificant in themselves1 but must appear yet more trifling when it is remembered that they are not cumulative1 inasmuch as the preliminary triangulation is itself dependent on the great trigonometrical survey4 ,let us understand clearly what are the various forms of survey which are or have been in progress in ,india4 ,there are three forms to be considered3--7#a7 ,the ,great ,trigonometrical ,surveys2 7#b7 ,the ,revenue ,surveys2 and 7#c7 the ,topographical ,surveys4 ,great trigonometrical operations are extended in a straight course from one measured base to another4 ,every precaution which modern skill and science can suggest is taken in the measurement of each base-line1 and in the various processes by which the survey is extended from one base-line to the other4 ,the accuracy with which work of this sort is conducted may be estimated from the following instance4 ,during the progress of the ,ordnance ,survey of ,great ,britain and ,ireland1 a base-line nearly eight miles long was measured near ,lough ,foyle1 in ,ireland1 and another nearly seven miles long on ,salisbury ,plain4 ,trigonometrical operations were then extended from ,lough ,foyle to ,salisbury ,plain1 a distance of about #cdj miles2 and the ,salisbury base-line was calculated from the observations made over this long arc4 ,the difference between the measured and calculated values of the base-line was less than five inches6 ,as we have stated1 the trigonometrical survey of ,india will bear comparison with the best work of our surveyors in ,england4 ,a revenue survey is prosecuted for the definition of the boundaries of estates and properties4 ,the operations of such a survey are therefore carried on conformably to those boundaries4 ,the topographical survey of a country is defined by ,sir ,a4 ,scott ,waugh to imply #8the measurement and delineation of the natural features of a country1 and the works of man thereon1 with the object of producing a complete and sufficiently accurate map4 ,being free from the trammels of boundaries of properties1 the principal lines of operations must conform to the features of the country1 and objects to be surveyed4' ,the only safe basis for the topographical survey of a country is a system of accurate triangulation4 ,and where the extent of country to be surveyed is large1 there will always be a great risk of the accumulation of error in the triangulation itself2 which must1 therefore1 be made to depend on the accurate results obtained by the great trigonometrical operations4 ,in order to secure this result1 fixed stations are established in the vicinity of the great trigonometrical series4 ,where this plan cannot be adopted1 a network of large symmetrical triangles is thrown over the district to be surveyed1 or boundary series of triangles are carried along the outline of the district or along convenient internal lines4 ,the former of these methods is applicable to a hilly district1 the latter to a flat country4 ,when the district to be surveyed has been triangulated1 the work of filling-in the topographical details is commenced4 ,each triangle being of moderate extent1 with sides from three to five miles in length1 and the angular points being determined1 as we have seen1 with great exactness1 it is evident that no considerable error can occur in filling-in the details4 ,hence1 methods can be adopted in the final topographical work which would not be suitable for triangulation4 ,the triangles can either be #8measured up1' or the observer may traverse from trigonometrical point to point1 taking offsets and intersections2 or1 lastly1 he may make use of the plane table4 ,the two first methods require little comment2 but the principle of plane-tabling enters so largely into ,indian surveying1 that this notice would be incomplete without a brief account of this simple and beautiful method4 ,the plane-table is a flat board turning on a vertical pivot4 ,it bears the chart on which the observer is planning the country4 ,suppose1 now1 that two points ,a and ,b are determined1 and that we require to mark in the position of a third point ,c3--,it is clear that if we observed with a theodolite the angles ,a ,b ,c and ,b ,a ,c1 we might lay these down on the chart with a protractor1 and so the position of ,c would be determined1 with an accuracy proportioned to the care with which the observations were made and the corresponding constructions applied to the chart4 ,but in #8plane-tabling' a more direct plan is adopted4 ,a ruler bearing sights1 resembling those of a rifle1 is so applied that the edge passing through the point ,a on the chart 7the observer being situated at the real station ,a7 passes through the point ,b on the chart1 the line of sight passing through the real station ,b4 ,the table being fixed in the position thus obtained1 the ruler is next directed so that its edge passes through ,a1 while the line of sight points to ,c4 ,a line is now ruled with a pencil through ,a towards ,c4 ,in a similar manner1 the table having been removed to the station ,b1 a pencil line is drawn through the point ,b on the chart towards ,c4 ,the two lines thus drawn determine by their intersection the place of ,c on the chart4 ,the above is only one instance of the modes in which a plane-table can be applied2 there are several others4 ,usually the magnetic compass is employed to fix the position of the table in accordance with the true bearing of the cardinal points4 ,also the bearings of several points are taken around each station2 and thus a variety of tests of the correctness of the work become applicable4 ,into such details as these ,i need not here enter4 ,it is sufficient that my readers should have been enabled to recognise the simple principles on which plane-tabling depends1 and the accuracy with which 7when suitable precautions are taken7 it can be applied as a method of observation subsidiary to the ordinary trigonometrical processes4 #8,a hilly country1' says ,sir ,a4 ,waugh1 #8offers the fairest field for the practice of plane-table surveys1 and the more rugged the surface the greater will be the relative advantages and facilities this system possesses over the methods of actual measurement4 ,on the other hand1 in flat lands the plane-table works at a disadvantage1 while the traverse system is facilitated4 ,consequently1 in such tracts1 the relative economy of the two systems does not offer so great a contrast as in the former4 ,in closely wooded or jungly tracts1 all kinds of survey operations are prosecuted at a disadvantage2 but in such localities1 the commanding points must be previously cleared for trigonometrical operations1 which facilitates the use of the table4' ,in whatever way the topographical details have been filled in1 a rigorous system of check must be applied to the work4 ,the system adopted is that of running lines across ground that has been surveyed4 ,this is done by the head of the party or by the chief assistant-surveyor4 ,a sufficient number of points are obtained in this way for comparison with the work of the detail surveyors2 and when the discrepancies exceed certain limits1 the work in which they appear is rejected4 ,owing to the extremely unhealthy1 jungly1 and rugged nature of the ground in which nearly all the ,indian surveys have been progressing1 it has not always been found practicable to check by regularly chained lines4 ,there are1 however1 other modes of testing plane-table surveys1 and as these entail less labour and expense in hilly and jungly tracts1 and are quite as effective if thoroughly carried out1 they have been adopted generally1 while the measured routes or check-lines have only been pursued under more favourable conditions4 ,colonel ,thuillier states that #8the inspection of the work of every detailed surveyor in the field has been rigorously enforced1 and the work of the field season is not considered satisfactory or complete unless this duty has been attended to4' ,the rules laid down to insure accuracy in the survey are--first1 that the greatest possible number of fixed points should be determined by regular triangulation2 secondly1 that the greatest possible number of plane-table fixings should be made use of within each triangle2 and lastly1 that eye-sketching should be reduced to a minimum4 ,if these rules are well attended to1 the surveyor can always rely on the value of the work performed by his subordinates4 ,but all these conditions cannot be secured in many parts of the ground allotted to the several topographical parties owing to the quantity of forest land and the extremely rugged nature of the country4 ,hence arises the necessity for test-lines to verify the details1 or for some vigorous system of check2 and this is more especially the case where native assistants are employed4 ,so soon as the country has been accurately planned1 the configuration of the ground has to be sketched up4 ,this process is the end and aim of all the preceding work4 ,the first point attended to is the arterial system1 or water drainage1 constituting the outfall of the country2 whence are deduced the lines of greatest depression of the ground4 ,next the watersheds or ridges of hills are traced in1 giving the highest level4 ,lastly1 the minor or subordinate features are drawn in with the utmost precision attainable4 #8,the outlines of table-land should be well defined1' says ,sir ,a4 ,waugh1 #8and ranges of hills portrayed with fidelity1 carefully representing the watersheds or divortia aquarum1 the spurs1 peaks1 depressions or saddles1 isthmuses or connecting-links of separate ranges1 and other ramifications4 ,the depressed points and isthmuses are particularly valuable1 as being either the sites of ordinary passes or points which new roads should conform to4' ,and here we must draw a distinction between survey and reconnaissance4 ,it is absolutely necessary in making a survey that the outlines of ground as defined by ridges1 water-courses1 and feet of hills should be rigorously fixed by actual observation and careful measurement4 ,in reconnoitring1 more is trusted to the eye4 ,the scale of the ,indian topographical survey is that of one inch per mile2 the scale of half an inch per mile being only resorted to in very densely wooded or jungly country1 containing a few inhabitants and little cultivated1 or where the climate is so dangerous that it is desirable to accelerate the progress of the survey4 ,on the scale of one inch per mile the practised draughtsman can survey about five square miles of average country per day4 ,in intricate ground1 intersected by ravines or covered by hills of irregular formation1 the work proceeds much more slowly2 on the other hand1 in open and nearly level country1 or where the hills have simple outlines1 the work will cost less and proceed more rapidly4 ,on the scale of one inch per mile all natural features 7such as ravines or watercourses7 more than a quarter of a mile in length can be clearly represented4 ,villages1 towns1 and cities can be shown1 with their principal streets and roads1 and the outlines of fortifications4 ,the general figure and extent of cultivated1 waste1 and forest lands can be delineated with more or less precision1 according to their extent4 ,irrigated rice-lands should be distinctly indicated1 since they generally exhibit the contour of the ground4 ,the relative heights of hills and depths of valleys should be determined during the course of a topographical survey4 ,these vertical elements of a survey can be ascertained by trigonometrical or by barometrical observations1 or by a combination of both methods4 #8,the barometer1' says ,sir ,a4 ,waugh1 #8is more especially useful for determining the level of low spots from which the principal trigonometrical stations are invisible4 ,in using this instrument1 however1 in combination with the other operations1 the relative differences of heights are to be considered the quantities sought1 so that all the results may be referable to the original trigonometrical station4 ,the height above the sea-level of all points coming under any of the following heads is especially to be determined1 for the purpose of illustrating the physical relief of the country3-- #8#ast4 ,the peaks and highest points of ranges4 #8#bnd4 ,all obligatory points required for engineering works1 such as roads1 drainage1 and irrigation1 viz43--the highest points or necks of valleys2 the lowest depressions or passes in ranges2 the junctions of rivers1 and dbouchements of rivers from ranges2 the height of inundation-level1 at moderate intervals of about three miles apart4 #8#crd4 ,principal towns or places of note4' ,of the various methods employed to indicate the steepness of slope1 that of eye-contouring seems alone to merit special comment4 ,in true contouring1 regular horizontal lines1 at fixed vertical intervals1 are traced over a country1 and plotted on to the maps4 ,this is an expensive and tedious process1 whereas eye-contouring is easy1 light1 and effective4 ,on this system all that is necessary is that the surveyor should consider what routes persons moving horizontally would pursue4 ,he draws lines on his chart approximating as closely as possible to these imaginary lines4 ,it is evident that when lines are thus drawn for different vertical elevations1 the resulting shading will be dark or light1 according as the slope is steep or gentle4 ,this method of shading affords scope as well for surveying skill as for draughtsmanship4 7,from ,once a ,week1 ,may #a1 #ahfi47 ,a ,,ship ,,attacked ,,by ,a ,,sword-,,fish4 ,i have always been puzzled to imagine how the #8nine-and-twenty knights of fame1' described in the #8,lay of the ,last ,minstrel1' managed to #8drink the red wine through the helmet barr'd4' ,but in nature we meet with animals which seem almost as inconveniently armed as those chosen knights1 who 444 quitted not their armour bright1 ,neither by day nor yet by night4 ,amongst such animals the sword-fish must be recognised as one of the most uncomfortably-armed creatures in existence4 ,the shark has to turn on his back before he can eat1 and the attitude scarcely seems suggestive of a comfortable meal4 ,but the sword-fish can hardly even by that arrangement get his awkwardly projecting snout out of the way4 ,yet doubtless this feature1 which seems so inconvenient1 is of great value to ,xiphias4 ,in some way as yet unknown it enables him to get his living4 ,whether he first kills some one of his neighbours with this instrument1 and then eats him at his leisure1 or whether he plunges it deep into the larger sort of fish1 and attaching himself to them in this way1 sucks nutriment from them while they are yet alive1 is not known to naturalists4 ,certainly1 he is fond of attacking whales1 but this may result not so much from gastronomic tastes as from a natural antipathy--envy1 perhaps1 at their superior bulk4 ,unfortunately for himself1 ,xiphias1 though cold-blooded1 seems a somewhat warm-tempered animal2 and1 when he is angered1 he makes a bull-like rush upon his foe1 without always examining with due care whether he is likely to take anything by his motion4 ,and when he happens to select for attack a stalwart ship1 and to plunge his horny beak through thirteen or fourteen inches of planking1 with perhaps a stout copper sheathing outside it1 he is apt to find some little difficulty in retreating4 ,the affair usually ends by his leaving his sword embedded in the side of the ship4 ,in fact1 no instance has ever been recorded of a sword-fish recovering his weapon 7if ,i may use the expression7 after making a lunge of this sort4 ,last ,wednesday the ,court of ,common ,pleas--rather a strange place1 by-the-bye1 for inquiring into the natural history of fishes--was engaged for several hours in trying to determine under what circumstances a sword-fish might be able to escape scot-free after thrusting his snout into the side of a ship1 ,the gallant ship #8,dreadnought1' thoroughly repaired1 and classed ,a #a at ,lloyd's1 had been insured for #c1jjjl4 against all the risks of the seas4 ,she sailed on ,march #aj1 #ahfd1 from ,colombo1 for ,london4 ,three days later1 the crew1 while fishing1 hooked a sword-fish4 ,xiphias1 however1 broke the line1 and a few moments after leaped half out of the water1 with the object1 it would seem1 of taking a look at his persecutor1 the #8,dreadnought4' ,probably he satisfied himself that the enemy was some abnormally large cetacean1 which it was his natural duty to attack forthwith4 ,be this as it may1 the attack was made1 and at four o'clock the next morning the captain was awakened with the unwelcome intelligence that the ship had sprung a leak4 ,she was taken back to ,colombo1 and thence to ,cochin1 where she was hove down4 ,near the keel was found a round hole1 an inch in diameter1 running completely through the copper sheathing and planking4 ,as attacks by sword-fish are included among sea risks1 the insurance company was willing to pay the damages claimed by the owners of the ship1 if only it could be proved that the hole had really been made by a sword-fish4 ,no instance had ever been recorded in which a sword-fish had been able to withdraw his sword after attacking a ship4 ,a defence was founded on the possibility that the hole had been made in some other way4 ,professor ,owen and ,mr4 ,frank ,buckland gave their evidence2 but neither of them could state quite positively whether a sword-fish which had passed its beak through three inches of stout planking could withdraw without the loss of its sword4 ,mr4 ,buckland said that fish have no power of #8backing1' and expressed his belief that he could hold a sword-fish by the beak2 but then he admitted that the fish had considerable lateral power1 and might so #8wriggle its sword out of a hole4' ,and so the insurance company will have to pay nearly six hundred pounds because an ill-tempered fish objected to be hooked1 and took its revenge by running full tilt against copper sheathing and oak planking4 7,from the ,daily ,news1 ,december #aa1 #ahfh47 ,,the ,,safety-,,lamp4 ,as recent colliery explosions have attracted a considerable amount of attention to the principle of the safety-lamp1 and questions have arisen respecting the extent of the immunity which the action of this lamp secures to the miner1 it may be well for me briefly to point out the true qualities of the lamp4 ,in the ,davy lamp a common oil-light is surrounded by a cylinder of wire-gauze4 ,when the air around the lamp is pure the flame burns as usual1 and the only effect of the gauze is somewhat to diminish the amount of light given out by the lamp4 ,but so soon as the air becomes loaded with the carburetted hydrogen gas generated in the coal-strata1 a change takes place4 ,the flame grows larger and less luminous4 ,the reason of the change is this3--,the flame is no longer fed by the oxygen of the air1 but is surrounded by an atmosphere which is partly inflammable2 and the inflammable part of the gas1 so fast as it passes within the wire cylinder1 is ignited and burns within the gauze4 ,thus the light now given out by the lamp is no longer that of the comparatively brilliant oil flame1 but is the light resulting from the combustion of carburetted hydrogen1 or #8fire damp1' as it is called2 and every student of chemistry is aware that the flame of this gas has very little illuminating power4 ,so soon as the miner sees the flame thus enlarged and altered in appearance he should retire4 ,but it is not true that explosion would necessarily follow if he did not do so4 ,the danger is great because the flame within the lamp is in direct contact with the gauze1 and if there is any defect in the wire-work1 the heat may make for itself an opening which--though small--would yet suffice to enable the flame within the lamp to ignite the gas outside4 ,so long1 however1 as the wire-gauze continues perfect1 even though it become red-hot1 there will be no explosion4 ,no authority is required to establish this point1 which has been proved again and again by experiment2 but ,i quote ,professor ,tyndall's words on the subject to remove some doubts which have been entertained on the matter4 #8,although a continuous explosive atmosphere1' he says1 #8may extend from the air outside through the meshes of the gauze to the flame within1 ignition is not propagated across the gauze4 ,the lamp may be filled with an almost lightless flame2 still explosion does not occur4 ,a defect in the gauze1 the destruction of the wire at any point by oxidation hastened by the flame playing against it1 would cause explosion2' and so on4 ,it need hardly be said1 however1 that1 imprudent as miners have often been1 no miner would remain where his lamp burned with the enlarged flame indicative of the presence of fire-damp4 ,the lamp should also be at once extinguished4 ,but here we touch on a danger which undoubtedly exists1 and--so far as has yet been seen--cannot be guarded against by any amount of caution4 ,supposing the miner sought to extinguish the lamp by blowing it out1 an explosion would almost certainly ensue1 since the flame can be forced mechanically through the meshes1 though it will not pass through them when it is burning in the ordinary way4 ,now of course no miner who had been properly instructed in the use of the safety-lamp would commit such a mistake as this4 ,but it happens1 unfortunately1 that sometimes the fire-damp itself forces the flame of the lamp through the meshes4 ,the gas frequently issues with great force from cavities in the coal 7in which it has been pent up71 when the pick of the miner breaks an opening for it4 ,in these circumstances an explosion is inevitable1 if the issuing stream of gas happen to be directed full upon the lamp4 ,fortunately1 however1 this is a contingency which does not often arise4 ,it is one of those risks of coal-mining which seem absolutely unavoidable by any amount of care or caution4 ,it would be well if it were only such risks as these that the miner had to face4 ,another peculiarity sometimes noticed when there is a discharge of fire-damp is worth mentioning4 ,it happens1 occasionally1 that the light will be put out owing to the absolute exclusion of air from the lamp4 ,this1 however1 can only happen when the gas issues in so large a volume that the atmosphere of the pit becomes irrespirable4 ,with the exception of the one risk which we have pointed out above1 the ,davy lamp may be said to be absolutely safe4 ,it is necessary1 however1 that caution and intelligence should be exhibited in its use4 ,on this point ,professor ,tyndall remarks that unfortunately the requisite intelligence is not often possessed nor the requisite caution exercised by the miner1 #8and the consequence is that even with the safety-lamp1 explosions still occur4' ,and he suggests that it would be well to exhibit to the miner in a series of experiments the properties of the valuable instrument which has been devised for his security4 #8,mere advice will not enforce caution1' he says2 #8but let the miner have the physical image of what he is to expect clearly and vividly before his mind1 and he will find it a restraining and monitory influence long after the effect of cautioning words has passed away4' ,a few words on the history of the invention may be acceptable4 ,early in the present century a series of terrible catastrophes in coal mines had excited the sympathy of enlightened and humane persons throughout the country4 ,in the year #ahac1 a society was formed at ,sunderland to prevent accidents in coal mines or at least to diminish their frequency1 and prizes were offered for the discovery of new methods of lighting and ventilating mines4 ,dr4 ,william ,reid ,clanny1 of ,bishopwearmouth1 presented to this society a lamp which burnt without explosion in an atmosphere heavily loaded with fire-damp2 for which invention the ,society of ,arts awarded him a gold medal4 ,the ,rev4 ,dr4 ,gray called the attention of ,sir ,humphry ,davy to the subject1 and that eminent chemist visited the coal mines in #ahae with the object of determining what form of lamp would be best suited to meet the requirements of the coal miners4 ,he invented two forms of lamp before discovering the principle on which the present safety-lamps are constructed4 ,this principle--the property1 namely1 that flame will not pass through small apertures--had been1 we believe1 discovered by ,stephenson1 the celebrated engineer1 some time before2 and a somewhat angry controversy took place respecting ,davy's claim to the honour of having invented the safety-lamp4 ,it seems admitted1 however1 by universal consent1 that ,davy's discovery of the property above referred to was made independently1 and also that he was the first to suggest the idea of using wire-gauze in place of perforated tin4 ,in comparing the present frequency of colliery explosions with what took place before the invention of the safety-lamp1 we must take into consideration the enormous increase in the coal trade since the introduction of steam machinery4 ,the number of miners now engaged in our coal mines is far in excess of the number employed at the beginning of the present century4 ,thus accidents in the present day are at once more common on account of the increased rapidity with which the mines are worked1 and when they occur there are more sufferers2 so that the frequency of colliery explosions in the opening years of the present century and the number of deaths resulting from them1 are in reality much more significant than they seem to be at first sight4 ,but even independently of this consideration1 the record of the colliery accidents which took place at that time is sufficiently startling4 ,seventy-two persons were killed in a colliery at ,north ,biddick at the commencement of the present century4 ,two explosions in #ahje1 at ,hepburn and ,oxclose1 left no less than forty-three widows and #aea children unprovided for4 ,in #ahjh1 ninety persons were killed in a coal-pit at ,lumley4 ,on ,may #bd1 #ahab1 ninety-one persons were killed by an explosion at ,felling ,colliery1 near ,gateshead4 ,and many more such accidents might readily be enumerated4 7,from the ,daily ,news1 ,december #d1 #ahfh47 ,,the ,,dust ,,we ,,have ,,to ,,breathe4 ,a microscopist1 ,mr4 ,dancer1 ,f4,r4,a4,s41 has been examining the dust of our cities4 ,the results are not pleasing4 ,we had always recognised city dust as a nuisance1 and had supposed that it derived the peculiar grittiness and flintiness of its structure from the constant macadamizing of city roads4 ,but it now appears that the effects produced by dust1 when1 as is usual1 it finds its way to our eyes1 our nostrils1 and our throats1 are as nothing compared with the mischief it is calculated to produce in a more subtle manner4 ,in every specimen examined by ,mr4 ,dancer animal life was abundant4 ,but the amount of #8molecular activity'--such is the euphuism under which what is exceedingly disagreeable to contemplate is spoken about--is variable according to the height at which the dust is collected4 ,and of all heights which these molecular wretches could select for the display of their activity1 the height of five feet is that which has been found to be the favourite4 ,just at the average height of the foot-passenger's mouth these moving organisms are always waiting to be devoured and to make us ill4 ,and this is not all4 ,as if animal abominations were insufficient1 a large proportion of vegetable matter also disports itself in the light dust of our streets4 ,the observations show that in thoroughfares where there are many animals engaged in the traffic1 the greater part of the vegetable matter thus floating about #8consists of what has passed through the stomachs of animals1' or has suffered decomposition in some way or other4 ,this unpleasing matter1 like the #8molecular activity1' floats about at a height of five feet1 or thereabouts4 ,after this1 one begins to recognise the manner in which some diseases propagate themselves4 ,what had been mysterious in the history of plagues and pestilences seems to receive at least a partial solution4 ,take cholera1 for example4 ,it has been shown by the clearest and most positive evidence that this disease is not propagated in any way save one--that is1 by the actual swallowing of the cholera poison4 ,in ,professor ,thudichum's masterly paper on the subject in the #8,monthly ,microscopical ,journal1' it is stated that doctors have inhaled a full breathing from a person in the last stage of this terrible malady without any evil effects4 ,yet the minutest atom of the cholera poison received into the stomach will cause an attack of cholera4 ,a small quantity of this matter drying on the floor of the patient's room1 and afterwards caused to float about in the form of dust1 would suffice to prostrate a houseful of people4 ,we can understand1 then1 how matter might be flung into the streets1 and1 after drying1 its dust be wafted through a whole district1 causing the death of hundreds4 ,one of the lessons to be learned from these interesting researches of ,mr4 ,dancer is clearly this1 that the watering-cart should be regarded as one of the most important of our hygienic institutions4 ,supplemented by careful scavengering1 it might be effective in dispossessing many a terrible malady which now holds sway from time to time over our towns4 7,from the ,daily ,news1 ,march #f1 #ahfi47 ,,photographic ,,ghosts4 ,on the outskirts of the ever-widening circle lighted up by science there is always a border-land wherein superstition holds sway4 #8,the arts and sciences may drive away the vulgar hobgoblin of darker days2 but they bring with them new sources of illusion4 ,the ghosts of old could only gibber2 the spirits of our day can read and write1 and play on divers musical instruments1 and quote ,shakespeare and ,milton4 ,it is not1 therefore1 altogether surprising to learn that they can take photographs also4 ,you go to have your photograph taken1 we will suppose1 desiring only to see your own features depicted in the carte2 and lo6 the spirits have been at work1 and a photographic phantom makes its appearance beside you4 ,it is true this phantom is of a hazy and dubious aspect3 the #8dull mechanic ghost' is indistinct1 and may be taken for anyone4 ,still1 it is not difficult for the eye of fancy to trace in it the lineaments of some departed friend1 who1 it is to be assumed1 has come to be photographed along with you4 ,in fact1 photography1 according to the spiritualist1 resembles what ,byron called-- ,the lightning of the mind1 ,which out of things familiar1 undesigned1 ,when least we deem of such1 calls up to view ,the spectres whom no exorcism can bind4 ,the phenomena of spiritual photography were first observed some years since1 and a set of carte photographs were sent from ,america to ,dr4 ,walker1 of ,edinburgh1 in which photographic phantoms were very obviously1 however indistinctly1 discernible4 ,more recently an ,english photographer noticed a yet stranger circumstance1 though he was too sensible to seek for a supernatural interpretation of it4 ,when he took a photograph with a particular lens1 there could be seen not only the usual portrait of the sitter1 but at some little distance a faint #8double1' exactly resembling the principal image4 ,superstitious minds might find this result even more distressing than the phantom photographic friend4 ,to be visited by the departed through the medium of a lens1 is at least not more unpleasing than to hold converse with spirits through an ordinary #8rapping' medium4 ,but the appearance of a #8double1' or #8fetch1' has ever been held by the learned in ghostly lore to signify approaching death4 ,fortunately both one and the other appearance can be very easily accounted for without calling in the aid of the supernatural4 ,at a recent meeting of the ,photographical ,society it was shown that an image may often be so deeply impressed on the glass that the subsequent cleaning of the plate1 even with strong acids1 will not completely remove the picture4 ,when the plate is used for receiving another picture1 the original image makes its reappearance1 and as it is too faint to be recognisable1 a highly susceptible imagination may readily transform it into the image of a departed friend4 ,the #8double' is generated by the well-known property of double refraction1 obtained by a lens under certain circumstances of unequal pressure1 or sometimes by inequalities in the process of annealing4 ,so vanish two ghosts which might have been more or less troublesome to those who are ready to see the supernatural in commonplace phenomena4 ,will the time ever come when no more such phantoms will remain to be exorcised8 7,from the ,daily ,news1 ,march #b1 #ahfi47 ,,the ,,oxford ,,and ,,cambridge ,,rowing ,,styles4 ,whatever opinion we may have of the result of the approaching contest 7#ahfi71 there can be no doubt that this year1 as in former years1 there is a striking dissimilarity between the rowing styles of the dark blue and the light blue oarsmen4 ,this dissimilarity makes itself obvious whether we compare the two boats as seen from the side1 or when the line of sight is directed along the length of either4 ,perhaps it is in the latter aspect that an unpractised eye will most readily detect the difference ,i am speaking of4 ,watch the ,cambridge boat approaching you from some distance1 or receding1 and you will notice in the rise and fall of the oars1 as so seen1 the following peculiarities--a long stay of the oar in the water1 a quick rise from and return to the water1 the oars remaining out of the water for the briefest possible interval of time4 ,in the case of the ,oxford boat quite a different appearance is presented--there is a short stay in the water1 a sharp rise from and return to it1 and between these the oars appear to hang over the water for a perceptible interval4 ,it is1 however1 when the boats are seen from the side that the meaning of these peculiarities is detected1 and also that the fundamental distinction between the two styles is made apparent to the experienced eye4 ,in the ,cambridge boat we recognise the long stroke and #8lightning feather' inculcated in the old treatises on rowing3 in the ,oxford boat we see these conditions reversed1 and in their place the #8waiting feather' and lightning stroke4 ,by the #8waiting feather' ,i do not refer to what is commonly understood by slow feathering1 but to a momentary pause 7scarcely to be detected when the crew is rowing hard7 before the simultaneous dash of the oars upon the first grip of the stroke4#ae ,and observing more closely--which1 by the way1 is no easy matter--as either boat dashes swiftly past1 we detect the distinctive peculiarities of #8work' by which the two styles are severally arrived at4 ,in the ,cambridge crew we see the first part of the stroke done with the shoulders--precisely according to the old-fashioned models--the arms straight until the body has fallen back to an almost upright position2 then comes the sharp drop back of the shoulders beyond the perpendicular1 the arms simultaneously doing their work1 so that as the swing back is finished1 the backs of the hands just touch the ribs in feathering4 ,all these things are quite in accordance with what used to be considered the perfection of rowing2 and1 indeed1 this style of rowing has some important good qualities and a very handsome appearance4 ,the lightning feather1 also1 which follows the long sweeping stroke1 is theoretically perfect4 ,now1 in the case of the ,oxford crew1 we observe a style which at first sight seems less excellent4 ,as soon as the oars are dashed down and catch their first hold of the water1 the arms as well as the shoulders of each oarsman are at work4#af ,the result is1 that when the back has reached an upright position1 the arms have already reached the chest1 and the stroke is finished4 ,thus the ,oxford stroke takes a perceptibly shorter time than the ,cambridge stroke2 it is also1 necessarily1 somewhat shorter in the water4 ,one would1 therefore1 say it must be less effective4 ,especially would an unpractised observer form this opinion1 because the ,oxford stroke seems to be much shorter in range than it is in reality4 ,there we have the secret of its efficiency4 ,it is actually as long as the ,cambridge stroke1 but is taken in a perceptibly shorter time4 ,what does this mean but that the oar is taken more sharply1 and1 therefore1 much more effectively1 through the water8 ,much more effectively so far as the actual conditions of the contest are concerned4 ,the modern racing outrigger requires a sharp impulse1 because it will take almost any speed we can apply to it4 ,it will also retain that speed between the strokes1 a consideration of great importance4 ,the old-fashioned racing-eights required to be continually under propulsion4 ,the lightning-feather was a necessity in their case1 for between every stroke the boat would lag terribly with a slow-feathering crew4 ,i do not say1 of course1 that the speed of a light outrigged craft does not diminish between the strokes4 ,anyone who has watched a closely contested bumping-race1 and noticed the way in which the sharply cut bow of the pursuing boat draws up to the rudder of the other as by a succession of impulses1 although either boat seen alone would seem to sweep on with almost uniform speed1 will know that the motion of the lightest boat is not strictly uniform4 ,but there is an immense difference between the almost imperceptible loss of way of a modern eight and the dead #8lag' in the old-fashioned craft4 ,and hence we get the following important consideration4 ,whereas with the old boats it was useless for a crew to attempt to give a very quick motion to their boat by a sharp1 sudden #8lift1' this plan is calculated to be1 of all others1 the most effective with the modern racing-eight4 ,it may seem1 at first sight1 that1 after all1 the result of the ,cambridge style should be as effective as that of the other4 ,if arms and shoulders do their work in both crews with equal energy--which we may assume to be the case--and if the number of strokes per minute is equal1 the actual propulsive energy ought to be equal likewise4 ,a little consideration will show that this is a fallacy4 ,if two men pull at a weight together they will move it farther with a given expenditure of energy than if first one and then the other apply his strength to the work4 ,and what is more to the purpose1 they will be able to move it faster4 ,so shoulders and arms working simultaneously will give a greater propulsive power than when working separately1 even though in the latter case each works with its fullest energy4 ,and not only so1 but by the simultaneous use of arms and shoulders1 that sharpness of motion can alone be given which is essential to the propulsion of a modern racing-boat4 ,i have said that the two crews are severally rowing in the style which has lately been peculiar to their respective ,universities4 ,but the ,cambridge crew is rowing in that form of the ,cambridge style which brings it nearest to the requirements of modern racing4 ,the faults of the style are subdued1 so to speak1 and its best qualities brought out effectively4 ,in one or two of the long series of defeats lately sustained by ,cambridge the reverse has been the case4 ,at present1 too1 there is a certain roughness about the ,oxford crew which encourages the hopes of the light blue supporters4 ,but it must be admitted that this roughness is rather apparent than real1 great as it seems1 and it will doubtless disappear before the day of encounter4 ,i venture to predict that the #8time' of the approaching race1 taken in conjunction with the state of the tide1 will show the present crews to be at least equal to the average4#ag 7,from the ,daily ,news1 ,april #ahfi47 ,,footnotes3 #ae ,the grip is never properly caught without the pause2 but anything beyond a momentary pause is a bad fault in style4 #af ,i write this with full knowledge that many ,oxford men deny the fact4 ,i have rowed behind ,cambridge1 ,oxford1 and ,london strokes1 and have several times taken the place 7number #b thwart7 of a ,london waterman in a four 7#8stroked' by ,john ,mackinney7 training for the ,thames ,regatta4 ,so that ,i have had ample opportunities for comparing different rowing styles2 and ,i am satisfied that the main defect of the real ,cambridge style was 7and perhaps is7 an exaggeration of the sound rule that a boat should be propelled rather by the body than by the arms4 ,the very swing in a ,cambridge boat shows that this must be so4 ,on the other hand1 the ,thames watermen do too much arm-work2 and hence seem to double a little over their oars4 ,i once rowed with some ,cambridge friends from ,london nearly to ,oxford and back1 taking a ,thames waterman as #8help4' ,we set him1 at first1 for our strokesman1 but we soon had to make him row bow1 for we could none of us stand his gripping1 arm-working style4 ,,betting ,,on ,,horse ,,races3 ,,or1 ,,the ,,state ,,of ,,the ,,odds4 ,there appears every day in the newspapers an account of the betting on the principal forthcoming races4 ,the betting on such races as the ,two ,thousand ,guineas1 the ,derby1 and the ,oaks1 often begins more than a year before the races are run2 and during the interval1 the odds laid against the different horses engaged in them vary repeatedly1 in accordance with the reported progress of the animals in their training1 or with what is learned respecting the intentions of their owners4 ,many who do not bet themselves1 find an interest in watching the varying fortunes of the horses which are held by the initiated to be leading favourites1 or to fall into the second rank1 or merely to have an outside chance of success4 ,it is amusing to notice1 too1 how frequently the final state of the odds is falsified by the event2 how some #8rank outsider' will run into the first place1 while the leading favourites are not even #8placed4' ,it is in reality a simple matter to understand the betting on races 7or contests of any kind71 yet it is astonishing how seldom those who do not actually bet upon races have any inkling of the meaning of those mysterious columns which indicate the opinion of the betting world respecting the probable results of approaching contests1 equine or otherwise4 ,let us take a few simple cases of #8odds1' to begin with2 and1 having mastered the elements of our subject1 proceed to see how cases of greater complexity are to be dealt with4 ,suppose the newspapers inform us that the betting is #b to #a against a certain horse for such and such a race1 what inference are we to deduce8 ,to learn this let us conceive a case in which the true odds against a certain event are as #b to #a4 ,suppose there are three balls in a bag1 one being white1 the others black4 ,then1 if we draw a ball at random1 it is clear that we are twice as likely to draw a black as to draw a white ball4 ,this is technically expressed by saying that the odds are #b to #a against drawing a white ball2 or #b to #a on 7that is1 in favour of7 drawing a black ball4 ,this being understood1 it follows that1 when the odds are said to be #b to #a against a certain horse1 we are to infer that1 in the opinion of those who have studied the performance of the horse1 and compared it with that of the other horses engaged in the race1 his chance of winning is equivalent to the chance of drawing one particular ball out of a bag of three balls4 ,observe how this result is obtained3 the odds are #b to #a1 and the chance of the horse is as that of drawing one ball out of a bag of three--three being the sum of the two numbers #b and #a4 ,this is the method followed in all such cases4 ,thus1 if the odds against a horse are #g to #a1 we infer that the cognoscenti consider his chance equal to that of drawing one particular ball out of a bag of eight4 ,a similar treatment applies when the odds are not given as so many to one4 ,thus1 if the odds against a horse are as #e to #b1 we infer that the horse's chance is equal to that of drawing a white ball out of a bag containing five black and two white balls--or seven in all4 ,we must notice also that the number of balls may be increased to any extent1 provided the proportion between the total number and the number of a specified colour remains unchanged4 ,thus1 if the odds are #e to #a against a horse1 his chance is assumed to be equivalent to that of drawing one white ball out of a bag containing six balls1 only one of which is white2 or to that of drawing a white ball out of a bag containing sixty balls1 of which ten are white-and so on4 ,this is a very important principle1 as we shall now see4 ,suppose there are two horses 7amongst others7 engaged in a race1 and that the odds are #b to #a against one1 and #d to #a against the other-what are the odds that one of the two horses will win the race8 ,this case will doubtless remind my readers of an amusing sketch by ,leech1 called--if ,i remember rightly--#8,signs of the ,commission4' ,three or four undergraduates are at a #8wine1' discussing matters equine4 ,one propounds to his neighbour the following question3 ,i say1 ,charley1 if the odds are #b to #a against ,rataplan1 and #d to #a against ,quick ,march1 what's the betting about the pair8'--#8,don't know1 ,i'm sure1' replies ,charley2 #8but ,i'll give you #f to #a against them4' ,the absurdity of the reply is1 of course1 very obvious2 we see at once that the odds cannot be heavier against a pair of horses than against either singly4 ,still1 there are many who would not find it easy to give a correct reply to the question4 ,what has been said above1 however1 will enable us at once to determine the just odds in this or any similar case4 ,thus-the odds against one horse being #b to #a1 his chance of winning is equal to that of drawing one white ball out of a bag of three1 one only of which is white4 ,in like manner1 the chance of the second horse is equal to that of drawing one white ball out of a bag of five1 one only of which is white4 ,now we have to find a number which is a multiple of both the numbers three and five4 ,fifteen is such a number4 ,the chance of the first horse1 modified according to the principle explained above1 is equal to that of drawing a white ball out of a bag of fifteen of which five are white4 ,in like manner1 the chance of the second is equal to that of drawing a white ball out of a bag of fifteen of which three are white4 ,therefore the chance that one of the two will win is equal to that of drawing a white ball out of a bag of fifteen balls of which eight 7five added to three7 are white4 ,there remain seven black balls1 and therefore the odds are #h to #g on the pair4 ,to impress the method of treating such cases on the mind of the reader1 let us take the betting about three horses--say #c to #a1 #g to #b1 and #i to #a against the three horses respectively4 ,then their respective chances are equal to the chance of drawing 7#a7 one white ball out of four1 one only of which is white2 7#b7 a white ball out of nine1 of which two only are white2 and 7#c7 one white ball out of ten1 one only of which is white4 ,the least number which contains four1 nine1 and ten is #ahj2 and the above chances1 modified according to the principle explained above1 become equal to the chance of drawing a white ball out of a bag containing #ahj balls1 when #de1 #dj1 and #ah 7respectively7 are white4 ,therefore1 the chance that one of the three will win is equal to that of drawing a white ball out of a bag containing #ahj balls1 of which #ajc 7the sum of #de1 #dj1 and #ah7 are white4 ,therefore1 the odds are #ajc to #gg on the three4 ,one does not hear in practice of such odds as #ajc to #gg4 ,but betting-men 7whether or not they apply just principles of computation to such questions1 is unknown to me7 manage to run very near the truth4 ,for instance1 in such a case as the above1 the odds on the three would probably be given as #d to #c--that is1 instead of #ajc to #gg 7or #dab to #cjh71 the published odds would be equivalent to #dab to #cji4 ,and here a certain nicety in betting has to be mentioned4 ,in running the eye down the list of odds1 one will often meet such expressions as #aj to #a against such a horse offered1 or #aj to #a wanted4 ,now1 the odds of #aj to #a taken may be understood to imply that the horse's chance is equivalent to that of drawing a certain ball out of a bag of eleven4 ,but if the odds are offered and not taken1 we cannot infer this4 ,the offering of the odds implies that the horse's chance is not better than that above mentioned1 but the fact that they are not taken implies that the horse's chance is not so good4 ,if no higher odds are offered against the horse1 we may infer that his chance is very little worse than that mentioned above4 ,similarly1 if the odds of #aj to #a are asked for1 we infer that the horse's chance is not worse than that of drawing one ball out of eleven2 if the odds are not obtained1 we infer that his chance is better2 and if no lower odds are asked for1 we infer that his chance is very little better4 ,thus1 there might be three horses 7,a1 ,b1 and ,c7 against whom the nominal odds were #aj to #a1 and yet these horses might not be equally good favourites1 because the odds might not be taken1 or might be asked for in vain4 ,we might accordingly find three such horses arranged thus3-- ,odds4 ,a #aj to #a 7wanted74 ,b #aj to #a 7taken74 ,c #aj to #a 7offered74 ,or these different stages might mark the upward or downward progress of the same horse in the betting4 ,in fact1 there are yet more delicate gradations1 marked by such expressions respecting certain odds1 as--offered freely1 offered1 offered and taken 7meaning that some offers only have been accepted71 taken1 taken and wanted1 wanted1 and so on4 ,as an illustration of some of the principles ,i have been considering1 let us take from the day's paper1#ah the state of the odds respecting the #8,two ,thousand ,guineas4' ,it is presented in the following form3-- ,,two ,,thousand ,,guineas4 #g to #b against ,rosicrucian 7off474 #f to #a against ,pace 7off42 #g to #a w474 #aj to #a against ,green ,sleeve 7off474 #ajj to #g against ,blue ,gown 7off474 #ahj to #hj against ,sir ,j4 ,hawley's lot 7t474 ,this table is interpreted thus3 bettors are willing to lay the same odds against ,rosicrucian as would be the true mathematical odds against drawing a white ball out of a bag containing two white and seven black balls2 but no one is willing to back the horse at this rate2 on the other hand1 higher odds are not offered against him4 ,hence it is presumable that his chance is somewhat less than that above indicated4 ,again1 bettors are willing to lay the same odds against ,pace as might fairly be laid against drawing one white ball out of a bag of seven1 one only of which is white2 but backers of the horse consider that they ought to get the same odds as might be fairly laid against drawing the white ball when an additional black ball had been put into the bag4 ,as respects ,green ,sleeve and ,blue ,gown1 bettors are willing to lay the odds which there would be1 respectively1 against drawing a white ball out of a bag containing--7#a7 eleven balls1 one only of which is white1 and 7#b7 one hundred and seven balls1 seven only of which are white4 ,now1 the three horses1 ,rosicrucian1 ,green ,sleeve1 and ,blue ,gown1 all belong to ,sir ,joseph ,hawley1 so that the odds about the three are referred to in the last statement of the list just given4 ,and since none of the offers against the three horses have been taken1 we may expect the odds actually taken about #8,sir ,joseph ,hawley's lot' to be more favourable than those obtained by summing up the three former in the manner we have already examined4 ,it will be found that the resulting odds 7offered7 against ,sir ,j4 ,hawley's lot--estimated in this way--should be1 as nearly as possible1 #acb to #hj4 ,we find1 however1 that the odds taken are #ahj to #hj4 ,hence1 we learn that the offers against some or all of the three horses are considerably short of what backers require2 or else that some person has been induced to offer far heavier odds against ,sir ,j4 ,hawley's lot than are justified by the fair odds against his horses1 severally4 ,i have heard it asked why a horse is said to be a favourite1 though the odds may be against him4 ,this is very easily explained4 ,let us take as an illustration the case of a race in which four horses are engaged to run4 ,if all these horses had an equal chance of winning1 it is very clear that the case would correspond to that of a bag containing four balls of different colours2 since1 in this case1 we should have an equal chance of drawing a ball of any assigned colour4 ,now1 the odds against drawing a particular ball would clearly be #c to #a4 ,this1 then1 should be the betting against each of the three horses4 ,if any one of the horses has less odds offered against him1 he is a favourite4 ,there may be more than one of the four horses thus distinguished2 and1 in that case1 the horse against which the least odds are offered is the first favourite4 ,let us suppose there are two favourites1 and that the odds against the leading favourite are #c to #b1 those against the other #b to #a1 and those against the best non-favourite #d to #a2 and let us compare the chances of the four horses4 ,i have not named any odds against the fourth1 because1 if the odds against all the horses but one are given1 the just odds against that one are determinable1 as we shall see immediately4 ,the chance of the leading favourite corresponds to the chance of drawing a ball out of a bag in which are three black and two white balls1 five in all2 that of the next to the chance of drawing a ball out of a bag in which are two black and one white ball1 three in all2 that of the third1 to the chance of drawing a ball out of a bag in which are four black balls and one white one1 five in all4 ,we take1 then1 the least number containing both five and three--that is1 fifteen2 and then the number of white balls1 corresponding to the chances of the three horses1 are respectively six1 five1 and three1 or fourteen in all2 leaving only one to represent the chance of the fourth horse 7against which the odds are therefore #ad to #a74 ,hence the chances of the four horses are respectively as the numbers six1 five1 three and one4 ,i have spoken above of the published odds4 ,the statements made in the daily papers commonly refer to wagers actually made1 and therefore the uninitiated might suppose that everyone who tried would be able to obtain the same odds4 ,this is not the case4 ,the wagers which are laid between practised betting-men afford very little indication of the prices which would be forced 7so to speak7 upon an inexperienced bettor4 ,book-makers--that is1 men who make a series of bets upon several or all of the horses engaged in a race--naturally seek to give less favourable terms than the known chances of the different horses engaged would suffice to warrant4 ,as they cannot offer such terms to the initiated1 they offer them-and in general success--fully--to the inexperienced4 ,it is often said that a man may so lay his wagers about a race as to make sure of gaining money whichever horse wins the race4 ,this is not strictly the case4 ,it is of course possible to make sure of winning if the bettor can only get persons to lay or take the odds he requires to the amount he requires4 ,but this is precisely the problem which would remain insoluble if all bettors were equally experienced4 ,suppose1 for instance1 that there are three horses engaged in a race with equal chances of success4 ,it is readily shown that the odds are #b to #a against each4 ,but if a bettor can get a person to take even betting against the first horse 7,a71 a second person to do the like about the second horse 7,b71 and a third to do the like about the third horse 7,c71 and if all these bets are made to the same amount--say #ajjjl4--then1 inasmuch as only one horse can win1 the bettor loses #ajjjl4 on that horse 7say ,a71 and gains the same sum on each of the two horses ,b and ,c4 ,thus1 on the whole1 he gains #ajjjl41 the sum laid out against each horse4 ,if the layer of the odds had laid the true odds to the same amount on each horse1 he would neither have gained nor lost4 ,suppose1 for instance1 that he laid #ajjjl4 to #ejjl4 against each horse1 and ,a won2 then he would have to pay #ajjjl4 to the backer of ,a1 and to receive #ejjl4 from each of the backers of ,b and ,c4 ,in like manner1 a person who had backed each horse to the same extent would neither lose nor gain by the event4 ,nor would a backer or layer who had wagered different sums necessarily gain or lose by the race2 he would gain or lose according to the event4 ,this will at once be seen1 on trial4 ,let us next take the case of horses with unequal prospects of success--for instance1 take the case of the four horses considered above1 against which the odds were respectively #c to #b1 #b to #a1 #d to #a1 and #ad to #a4 ,here1 suppose the same sum laid against each1 and for convenience let this sum be #hdl4 7because #hd contains the numbers #c1 #b1 #d1 and #ad74 ,the layer of the odds wagers #hdl4 to #efl4 against the leading favourite1 #hdl4 to #dbl4 against the second horse1 #hdl4 to #bal4 against the third1 and #hdl4 to #fl4 against the fourth4 ,whichever horse wins1 the layer has to pay #hdl42 but if the favourite wins1 he receives only #dbl4 on one horse1 #bal4 on another1 and #fl4 on the third--that is #fil4 in all1 so that he loses #ael42 if the second horse wins1 he has to receive #efl41 #bal41 and #fl4--or #hcl4 in all1 so that he loses #al42 if the third horse wins1 he receives #efl41 #dbl41 and #fl4--or #ajdl4 in all1 and thus gains #bjl42 and lastly1 if the fourth horse wins1 he has to receive #efl41 #dbl41 and #bll4--or #aail4 in all1 so that he gains #cel4 ,he clearly risks much less than he has a chance 7however small7 of gaining4 ,it is also clear that in all such cases the worst event for the layer of the odds is1 that the favourite should win4 ,accordingly1 as professional book-makers are nearly always layers of odds1 one often finds the success of a favourite spoken of in the papers as a #8great blow for the book-makers1' while the success of a rank outsider will be described as #8a misfortune to backers4' ,but there is another circumstance which tends to make the success of a favourite a blow to layers of the odds and vice vers4 ,in the case we have supposed1 the money actually pending about the four horses 7that is1 the sum of the amount laid for and against them7 was #adjl4 as respects the favourite1 #abfl4 as respects the second1 #ajel4 as respects the third1 and #ijl4 as respects the fourth4 ,but as a matter of fact the amounts pending about the favourites bear always a much greater proportion than the above to the amounts pending about outsiders4 ,it is easy to see the effect of this4 ,suppose1 for instance1 that instead of the sums #hdl4 to #efl41 #hdl4 to #dbl41 #hdl4 to #bal41 and #hdl4 to #fl41 a book-maker had laid #hdjjl4 to #efjjl41 #hdjl4 to #dbjl41 #hdl4 to #bal41 and #adl4 to #al41 respectively--then it will easily be seen that he would lose #giehl4 by the success of the favourite2 whereas he would gain #dghbl4 by the success of the second horse1 #eicgl4 by that of the third1 and #fjbgl4 by that of the fourth4 ,i have taken this as an extreme case2 as a general rule1 there is not so great a disparity as has been here assumed between the sums pending on favourites and outsiders4 ,finally1 it may be asked whether1 in the case of horses having unequal chances1 it is possible that wagers can be so proportioned 7just odds being given and taken71 that1 as in the former case1 a person backing or laying against all the four shall neither gain nor lose4 ,it is so4 ,all that is necessary is1 that the sum actually pending about each horse shall be the same4 ,thus1 in the preceding case1 if the wagers #il4 to #fl41 #ajl4 to #el41 #abl4 to #cl41 and #adl4 to #al41 are either laid or taken by the same person1 he will neither gain nor lose by the event1 whatever it may be4 ,and therefore1 if unfair odds are laid or taken about all the horses1 in such a manner that the amounts pending on the several horses are equal 7or nearly so71 the unfair bettor must win by the result4 ,say1 for instance1 that instead of the above odds1 he lays #hl4 to #fl41 #il4 to #el41 #aal4 to #cl4 and #acl4 to #al41 against the four horses respectively2 it will be found that he must win #al4 ,or if he takes the odds #ahl4 to #aal41 #bjl4 to #il41 #bdl4 to #el41 and #bhl4 to #al4 7the just odds being #ahl4 to #abl41 #bjl4 to #ajl41 #bdl4 to #fl41 and #bhl4 to #bl4 respectively71 he will win #al4 by the race4 ,so that1 by giving or taking such odds to a sufficiently great amount1 a bettor would be certain of pocketing a large sum1 whatever the event of a given race might be4 ,in every instance1 a man who bets on a race must risk his money1 unless he can succeed in taking unfair advantages over those with whom he bets4 ,my readers will conceive how small must be the chance that an unpractised bettor will gain anything but dearly-bought experience by speculating on horse-races4 ,i would recommend those who are tempted to hold another opinion to follow the plan suggested by ,thackeray in a similar case--to take a good look at professional and practised betting-men1 and to decide #8which of those men they are most likely to get the better of' in turf transactions4 7,from ,chambers's ,journal1 ,july #ahfi47 ,,footnotes3 #ag ,the race 7that of #ahfi7 was one of the best ever rowed1 and the time of the winners 7,oxford7 better than in any former race4 #ah ,this article was written early in ,march #ahfh4 ,,squaring ,,the ,,circle4 ,there must be a singular charm about insoluble problems1 since there are never wanting persons who are willing to attack them4 ,i doubt not that at this moment there are persons who are devoting their energies to ,squaring the ,circle1 in the full belief that important advantages would accrue to science--and possibly a considerable pecuniary profit to themselves--if they could succeed in solving it4 ,quite recently1 applications have been made to the ,paris ,academy of ,sciences1 to ascertain what was the amount which that body was authorised to pay over to anyone who should square the circle4 ,so seriously1 indeed1 was the secretary annoyed by applications of this sort1 that it was found necessary to announce in the daily journals that not only was the ,academy not authorised to pay any sum at all1 but that it had determined never to give the least attention to those who fancied they had mastered the famous problem4 ,it is a singular circumstance that people have even attacked the problem without knowing exactly what its nature is4 ,one ingenious workman1 to whom the difficulty had been propounded1 actually set to work to invent an arrangement for measuring the circumference of the circle2 and was perfectly satisfied that he had thus solved a problem which had mastered all the mathematicians of ancient and modern times4 ,that we may not fall into a similar error1 let us clearly understand what it is that is required for the solution of the problem of #8squaring the circle4' ,to begin with1 we must note that the term #8squaring the circle' is rather a misnomer2 because the true problem to be solved is the determination of the length of a circle's circumference when the diameter is known4 ,of course1 the solution of this problem1 or1 as it is termed1 the rectification of the circle1 involves the solution of the other1 or the quadrature1 of the circle4 ,but it is well to keep the simpler issue before us4 ,many have supposed that there exists some exact relation between the circumference and the diameter of the circle1 and that the problem to be solved is the determination of this relation4 ,suppose1 for example1 that the approximate relation discovered by ,archimedes 7who found1 that if a circle's diameter is represented by seven1 the circumference may be almost exactly represented by twenty-two7 were strictly correct1 and that ,archimedes had proved it to be so2 then1 according to this view1 he would have solved the great problem2 and it is to determine a relation of some such sort that many persons have set themselves4 ,now1 undoubtedly1 if any relation of this sort could be established1 the problem would be solved2 but as a matter of fact no such relation exists1 and the solution of the problem does not require that there should be any relation of the sort4 ,for example1 we do not look on the determination of the diagonal of a square 7whose side is known7 as an insoluble1 or as otherwise than a very simple problem4 ,yet in this case no exact relation exists4 ,we cannot possibly express both the side and the diagonal of a square in whole numbers1 no matter what unit of measurement we adopt3 or1 to put the matter in another way1 we cannot possibly divide both the side and the diagonal into equal parts 7which shall be the same along each71 no matter how small we take the parts4 ,if we divide the side into #a1jjj parts1 there will be #a1dad such parts1 and a piece over in the diagonal2 if we divide the side into #aj1jjj parts1 there will be #ad1adb1 and still a little piece over1 in the diagonal2 and so on for ever4 ,similarly1 the mere fact that no exact relation exists between the diameter and the circumference of a circle is no bar whatever to the solution of the great problem4 ,before leaving this part of the subject1 however1 ,i may mention a relation which is very easily remembered1 and is very nearly exact--much more so1 at any rate1 than that of ,archimedes4 ,write down the numbers #aac1cee1 that is1 the first three odd numbers each repeated twice over4 ,then separate the six numbers into two sets of three1 thus1--#aac7 #cee1 and proceed with the division thus indicated4 ,the result1 #cadaeibi4441 expresses the circumference of a circle whose diameter is #a1 correctly to the sixth decimal place1 the true relation being #cadaeibfe4 ,again1 many people imagine that mathematicians are still in a state of uncertainty as to the relation which exists between the circumference and the diameter of the circle4 ,if this were so1 scientific societies might well hold out a reward to anyone who could enlighten them2 for the determination of this relation 7with satisfactory exactitude7 may be held to lie at the foundation of the whole of our modern system of mathematics4 ,i need hardly say that no doubt whatever rests on the matter4 ,a hundred different methods are known to mathematicians by which the circumference may be calculated from the diameter with any required degree of exactness4 ,here is a simple one1 for example3--,take any number of the fractions formed by putting one as a numerator over the successive odd numbers4 ,add together the alternate ones beginning with the first1 which1 of course1 is unity4 ,add together the remainder4 ,subtract the second sum from the first4 ,the remainder will express the circumference 7the diameter being taken as unity7 to any required degree of exactness4 ,we have merely to take enough fractions4 ,the process would1 of course1 be a very laborious one1 if great exactness were required1 and as a matter of fact mathematicians have made use of much more convenient methods for determining the required relation3 but the method is strictly exact4 ,the largest circle we have much to do with in scientific questions is the earth's equator4 ,as a matter of curiosity1 we may inquire what the circumference of the earth's orbit is2 but as we are far from being sure of the exact length of the radius of that orbit 7that is1 of the earth's distance from the sun71 it is clear that we do not need a very exact relation between the circumference and the diameter in dealing with that enormous circle4 ,confining ourselves1 therefore1 to the circle of the earth's equator1 let us see what exactness we seem to require4 ,we will suppose for a moment that it is possible to measure round the earth's equator without losing count of a single yard1 and that we want to gather from our estimate what the diameter of this great circle may be4 ,this seems1 indeed1 the only use to which1 in this case1 we can put our knowledge of the relation we are dealing with4 ,we have then a circle some twenty-five thousand miles round1 and each mile contains one thousand seven hundred and sixty yards3 or in all there are some forty-four million yards in the circumference1 and therefore 7roughly7 some fourteen million yards in the diameter of this great circle4 ,hence1 if our relation is correct within a fourteen-millionth part of the diameter1 or a forty-four millionth part of the circumference1 we are safe from any error exceeding a yard4 ,all we want1 then1 is that the number expressing the circumference 7the diameter being unity7 should be true to the eighth decimal place1 as quoted above 7p4 #bia1 l4 #e74 ,but as ,i have said1 mathematicians have not been content with a computation of this sort4 ,they have calculated the number not to the eighth1 but to the six hundred and twentieth decimal place4 ,now1 if we remember that each new decimal makes the result ten times more exact1 we shall begin to see what a waste of time there has been in this tremendous calculation4 ,we all remember the story of the horse which had twenty-four nails in its shoes1 and was valued at the sum obtained by adding together a farthing for the first nail1 a halfpenny for the next1 a penny for the next1 and so on1 doubling twenty-four times4 ,the result was counted by thousands of pounds4 ,the old miser who paid at a similar rate for a grave eighteen feet deep 7doubling for each foot71 killed himself when he heard the total4 ,but now consider the effect of multiplying by ten1 six hundred and twenty times4 ,a fraction1 with that enormous number for denominator1 and unity for numerator1 expresses the minuteness of the error which would result if the #8long value' of the circumference were made use of4 ,let an illustration show the force of this3-- ,it has been estimated that light1 which could eight times circle the earth in a second1 takes #ej1jjj years in reaching us from the faintest stars seen in ,lord ,rosse's giant reflector4 ,suppose we knew the exact length of the tremendous line which extends from the earth to such a star1 and wanted1 for some inconceivable purpose1 to know the length of the circumference of a circle1 of which that line was the radius4 ,the value deduced from the above-mentioned calculation of the relation between the circumference and the diameter would differ from the truth by a length which would be imperceptible under the most powerful microscope ever yet constructed4 ,nay1 the radius we have conceived1 enormous as it is1 might be increased a million-fold1 or a million times a million-fold1 with the same result4 ,and the area of the circle formed with this increased radius would be determinable with so much accuracy1 that the error1 if presented in the form of a minute square1 would be utterly imperceptible under a microscope a million times more powerful than the best ever yet constructed by man4 ,not only has the length of the circumference been calculated once in this unnecessarily exact manner1 but a second calculator has gone over the work independently4 ,the two results are of course identical figure for figure4 ,it will be asked then1 what is the problem about which so great a work has been made8 ,the problem is1 in fact1 utterly insignificant2 its only interest lies in the fact that it is insoluble--a property which it shares along with many other problems1 as the trisection of an angle1 the duplication of a cube1 and so on4 ,the problem is simply this3 ,having given the diameter of a circle1 to determine1 by a geometrical construction1 in which only straight lines and circles shall be made use of1 the side of a square1 equal in area to the circle4 ,as ,i have said1 the problem is solved1 if1 by a construction of the kind described1 we can determine the length of the circumference2 because then the rectangle under half this length and the radius is equal in area to the circle1 and it is a simple problem to describe a square equal to a given rectangle4 ,to illustrate the kind of construction required1 ,i give an approximate solution which is remarkably simple1 and1 so far as ,i am aware1 not generally known4 ,describe a square about the given circle1 touching it at the ends of two diameters1 ,,aob1 ,,cob1 at right angles to each other1 and join ,,ca2 let ,,coae be one of the quarters of the circumscribing square1 and from ,e draw ,,eg1 cutting off from ,,ao a fourth part ,,ag of its length1 and from ,,ac the portion ,,ah4 ,then three sides of the circumscribing square together with ,,ah are very nearly equal to the circumference of the circle4 ,the difference is so small1 that in a circle two feet in diameter1 it would be less than the two-hundredth part of an inch4 ,if this construction were exact1 the great problem would have been solved4 ,one point1 however1 must be noted2 the circle is of all curved lines the easiest to draw by mechanical means4 ,but there are others which can be so drawn4 ,and if such curves as these be admitted as available1 the problem of the quadrature of the circle can be readily solved4 ,there is a curve1 for instance1 invented by ,dinostratus1 which can readily be described mechanically1 and has been called the quadratrix of ,dinostratus1 because it has the property of thus solving the problem we are dealing with4 ,as such curves can be described with quite as much accuracy as the circle--for1 be it remembered1 an absolutely perfect circle has never yet been drawn--we see that it is only the limitations which geometers have themselves invented that give this problem its difficulty4 ,its solution has1 as ,i have said1 no value2 and no mathematician would ever think of wasting a moment over the problem--for this reason1 simply1 that it has long since been demonstrated to be insoluble by simple geometrical methods4 ,so that1 when a man says he has squared the circle 7and many will say so1 if one will only give them a hearing71 he shows that either he wholly misunderstands the nature of the problem1 or that his ignorance of mathematics has led him to mistake a faulty for a true solution4 7,from ,chambers's ,journal1 ,january #af1 #ahfi47 ,a ,,new ,,theory ,,of ,,achilles' ,,shield4 ,a distinguished classical authority has remarked that the description of ,achilles' shield occupies an anomalous position in ,homer's #8,iliad4' ,on the one hand1 it is easy to show that the poem--for the description may be looked on as a complete poem--is out of place in the #8,iliad2' on the other1 it is no less easy to show that ,homer has carefully led up to the description of the shield by a series of introductory events4 ,i propose to examine1 briefly1 the evidence on each of these points1 and then to exhibit a theory respecting the shield which may appear bizarre enough on a first view1 but which seems to me to be supported by satisfactory evidence4 ,an argument commonly urged against the genuineness of the #8,shield of ,achilles' is founded on the length and laboured character of the description4 ,even ,grote1 whose theory is that ,homer's original poem was not an ,iliad1 but an ,achilleis1 has admitted the force of this argument4 ,he finds clear evidence that from ,book ,,ii4 to ,book ,,xx4 ,homer has been husbanding his resources for the more effective description of the final conflict4 ,he therefore concedes the possibility that the #8,shield of ,achilles' may be an interpolation--perhaps the work of another hand4 ,it appears to me1 however1 that the mere length of the description is no argument against the genuineness of the passage4 ,events have1 indeed1 been hastening to a crisis up to the end of ,book ,,xvii41 and the action is checked in a marked manner by the #8,oplopia' in ,book ,,xviii4 ,yet it is quite in ,homer's manner to introduce1 between two series of important events1 an interval of comparative inaction1 or at least of events wholly different in character from those of either series4 ,we have a marked instance of this in ,books ,,ix4 and ,x4 ,here the appeal to ,achilles and the night-adventure of ,diomed and ,ulysses are interposed between the first victory of the ,trojans and the great struggle in which ,patroclus is slain1 and ,agamemnon1 ,ulysses1 ,diomed1 ,machaon1 and ,eurypylus wounded4#ai ,in fact1 one cannot doubt that in such an arrangement ,homer exhibits admirable taste and judgment4 ,the contrast between action and inaction1 or between the confused tumult of a heady conflict and the subtle advance of the two ,greek heroes1 is conceived in the true poetic spirit4 ,the dignity and importance of the action1 and the interest of the interposed events1 are alike enhanced4 ,indeed1 there is scarcely a noted author whose works do not afford instances of corresponding contrasts4 ,how skilfully1 for example1 has ,shakespeare interposed the #8bald1 disjointed chat' of the sleepy porter between the conscience-wrought horror of ,duncan's murderers and the #8horror1 horror1 horror' which #8tongue nor heart could not conceive nor name' of his faithful followers4 ,nor will the reader need to be reminded of the frequent and effective use of the contrast between the humorous and the pathetic by others4 ,the laboured character of the description of the shield is an argument--though not1 perhaps1 a very striking one--for the independent origin of the poem4 ,but the arguments on which ,i am disposed to lay most stress lie nearer the surface4 ,scarcely anyone1 ,i think1 can have read the description of the shield without a feeling of wonder that ,homer should describe the shield of a mortal hero as adorned with so many and such important objects4 ,we find the sun and moon1 the constellations1 the waves of ocean1 and a variety of other objects1 better suited to adorn the temple of a great deity than the shield of a warrior1 however noble and heroic4 ,the objects depicted even on the gis of ,zeus are much less important4 ,there is certainly no trace in the #8,iliad' of a wish on ,homer's part to raise the dignity of mortal heroes at the expense of ,zeus1 yet the gis is thus succinctly described3-- ,fring'd round with ever-fighting snakes1 though it was drawn to life1 ,the miseries and deaths of fight2 in it frown'd bloody ,strife1 ,in it shone sacred ,fortitude1 in it fell ,pursuit flew1 ,in it the monster ,gorgon's head1 in which held out to view ,were all the dire ostents of ,jove4--,chapman's ,translation4 ,five lines here1 as in the original1 suffice for the description of ,jove's gis1 while one hundred and thirty lines are employed in the description of the celestial and terrestrial objects depicted on the shield of ,achilles4 ,another circumstance attracts notice in the description of ,achilles' armour--the disproportionate importance attached to the shield4 ,undoubtedly1 the shield was that portion of a hero's armour which admitted of the freest application of artistic skill4 ,yet this consideration is not sufficient to account for the fact1 that while so many lines are given to the shield1 the helmet1 corselet1 and greaves are disposed of in four4 ,but the argument on which ,i am inclined to lay most stress is the occurrence elsewhere of a description which is undoubtedly only another version of the #8,shield of ,achilles4' ,the #8,shield of ,hercules' occurs in a poem ascribed to ,hesiod4 ,but whatever opinion may be formed respecting the authorship of the description1 there can be no doubt that it is not ,hesiod's work4 ,it exhibits no trace of his dry1 didactic1 somewhat heavy style4 ,elton ascribes the #8,shield of ,hercules' to an imitator of ,homer1 and in support of this view points out those respects in which the poem resembles1 and those in which it is inferior to1 the #8,shield of ,achilles4' ,the two descriptions are1 however1 absolutely identical in many places2 and this would certainly not have happened if one had been an honest imitation of the other4 ,and those parts of the #8,shield of ,hercules1' which have no counterparts in the #8,shield of ,achilles1' are too well conceived and expressed to be ascribed to a very inferior poet--a poet so inferior as to be reduced to the necessity of simply reproducing ,homer's words in other parts of the poem4 ,those parts which admit of comparison--where1 for instance1 the same objects are described1 but in different terms--are certainly inferior in the #8,shield of ,hercules4' ,the description is injured by the addition of unnecessary or inharmonious details4 ,elton speaks1 accordingly1 of these portions as if they were expansions of the corresponding parts of the #8,shield of ,achilles4' ,this appears to me a mistake4 ,it seems far more likely that both descriptions are by the same poet4 ,it is not necessary for the support of my theory that this poet should be ,homer1 but ,i think both descriptions show undoubted traces of his handiwork4 ,indeed1 all known imitations of ,homer are so easily recognisable as the work of inferior poets1 that ,i should have thought no doubt could exist on this point1 but for the attention which the ,german theory respecting the #8,iliad' has received4 ,assigning both poems to ,homer1 the #8,shield of ,hercules' may be regarded1 not as an expansion 7in parts7 of the #8,shield of ,achilles1' but as an earlier work of ,homer's1 improved and pruned by his maturer judgment1 when he desired to fit it into the plan of the #8,iliad4' ,or rather1 each poem may be looked on as an abridgment 7the #8,shield of ,hercules' the earlier7 of an independent work on a subject presently to be mentioned4 ,it is next to be shown that in the events preceding the #8,oplopia1' there is a preparation for the introduction of a separate poem4 ,in the first place1 every reader of ,homer is familiar with the fact that the poet constantly makes use1 when occasion serves1 of expressions1 sentences1 often even of complete passages1 which have been already applied in a corresponding1 or occasionally even in a wholly different relation4 ,the same epithets are repeatedly applied to the same deity or hero4 ,a long message is delivered in the very words which have been already used by the sender of the message4 ,in one well-known instance 7in ,book ,,ii471 not only is a message delivered thus1 but the person who has received it repeats it to others in precisely the same terms4 ,in the combat between ,hector and ,ajax 7,book ,,vi471 the flight of ,ajax's spear and the movement by which ,hector avoids the missile1 are described in six lines1 differing only as to proper names from those which had been already used in describing the encounter between ,paris and ,menelaus 7,book ,,iii474 ,this peculiarity would be a decided blemish in a written poem4 ,tennyson1 indeed1 occasionally copies ,homer's manner--for instance1 in #8,enid1' he twice repeats the line-- ,as careful robins eye the delver's toil2-- but with a good taste which prevents the repetition from becoming offensive4 ,the fact is1 that the peculiarity marks ,homer as the singer1 not the writer1 of poetry4 ,i would not be understood as accepting the theory1 according to which the #8,iliad' is a mere string of ballads4 ,i imagine that no one who justly appreciates that noble poem would be willing to countenance such a theory4 ,but that the whole poem was sung by ,homer at those prolonged festivals which formed a characteristic peculiarity of ,achaian manners seems shown1 not only by what we learn respecting the later #8rhapsodists1' but by the internal evidence of the poem itself4#bj ,homer1 reciting a long and elaborate poem of his own composition1 occasionally varying the order of events1 or adding new episodes1 extemporized as the song proceeded1 would exhibit the peculiarity invariably observed in the #8improvisatore1' of using1 more than once1 expressions1 sentences1 or passages which happened to be conveniently applicable4 ,the art of extemporizing depends on the capacity for composing fresh matter while the tongue is engaged in the recital of matter already composed4 ,anyone who has watched a clever improvisatore cannot fail to have noticed that1 though gesture is aptly wedded to words1 the thoughts are elsewhere4 ,in the case1 therefore1 of an improvisatore1 or even of a rhapsodist reciting from memory1 the occasional recurrence of a well-worn form of words serves as a relief to the strained invention or memory4 ,we have reason then for supposing that if ,homer had1 in his earlier days1 composed a poem which was applicable1 with slight alterations1 to the story of the #8,iliad1' he would endeavour1 by a suitable arrangement of the plan of his narrative1 to introduce the lines whose recital had long since become familiar to him4 ,evidence of design in the introduction of the #8,shield of ,achilles' certainly does not seem wanting4 ,it is by no means necessary to the plot of the #8,iliad' that ,achilles should lose the celestial armour given to ,peleus as a dowry with ,thetis4 ,on the contrary1 ,homer has gone out of his way to render the labours of ,vulcan necessary4 ,patroclus has to be so ingeniously disposed of1 that while the armour he had worn is seized by ,hector1 his body is rescued1 as are also the horses and chariot of ,achilles4 ,we have the additional improbability that the armour of the great ,achilles should fit the inferior warriors ,patroclus and ,hector4 ,indeed1 that the armour should fit ,hector1 or rather that ,hector should fit the armour1 the aid of ,zeus and ,ares has to be called in-- ,to this ,jove's sable brows did bow2 and he made fit his limbs ,to those great arms1 to fill which up the war-god enter'd him ,austere and terrible1 his joints and every part extends ,with strength and fortitude4--,chapman's ,translation4 ,it is clear that the narrative would not have been impaired in any way1 while its probability and consistency would have been increased1 if ,patroclus had fought in his own armour4 ,the death of ,patroclus would in any case have been a cause sufficient to arouse the wrath of ,achilles against ,hector--though certainly the hero's grief for his armour is nearly as poignant as his sorrow for his friend4 ,it appears probable1 then1 that the description of ,achilles' ,shield is an interpolation--the poet's own work1 however1 and brought in by him in the only way he found available4 ,the description clearly refers to the same object which is described 7here1 also1 only in part7 in the #8,shield of ,hercules4' ,the original description1 doubtless1 included all that is found in both #8shields1' and probably much more4 ,what1 then1 was the object to which the original description applied8 ,an object1 ,i should think1 far more important than a warrior's shield4 ,i imagine that anyone who should read the description without being aware of its accepted interpretation1 would consider that the poet was dealing with an important series of religious sculptures1 possibly that he was describing the dome of a temple adorned with celestial and terrestrial symbols4 ,in ,egypt there are temples of a vast antiquity1 having a dome1 on which a zodiac--or1 more correctly1 a celestial hemisphere--is sculptured with constellation-figures4 ,and we now learn1 from ancient ,babylonian and ,assyrian sculptures1 that these ,egyptian zodiacs are in all probability merely copies 7more or less perfect7 of yet more ancient ,chaldan zodiacs4 ,one of these ,babylonian sculptures is figured in ,rawlinson's #8,ancient ,monarchies4' ,it seems probable that in a country where ,sabanism1 or star-worship1 was the prevailing form of religion1 yet more imposing proportions would be given to such zodiacs than in ,egypt4 ,my theory1 then1 respecting the shield of ,achilles is this-- ,i conceive that ,homer1 in his eastern travels1 visited imposing temples devoted to astronomical observation and star-worship2 and that nearly every line in both #8shields' is borrowed from a poem in which he described a temple of this sort1 its domed zodiac1 and those illustrations of the labours of different seasons and of military or judicial procedures which the astrological proclivities of star-worshippers led them to associate with the different constellations4 ,i think there are arguments of some force to be urged in support of this theory1 fanciful as it may seem at a first view4 ,in the first place1 it is necessary that the constellations recognised in ,homer's time 7not necessarily1 or probably1 by ,homer7 should be distinguished from later inventions4 ,aratus1 writing long after ,homer's date1 mentions forty-five constellations4 ,these were probably derived1 without exception1 from the globe of ,eudoxus4 ,remembering the tendency which astronomers have shown1 in all ages1 to add to the list of constellations1 we may assume that in ,homer's time the number was smaller4 ,probably there were some fifteen northern and ten southern constellations1 besides the twelve zodiacal signs4 ,the smaller constellations mentioned by ,aratus doubtless formed parts of larger figures4 ,anyone who studies the heavens will recognise the fact that the larger constellations have been robbed of their just proportions to form the smaller asterisms4 ,corona ,borealis was the right arm of ,bootes1 ,ursa ,minor was a wing of ,draco 7now wingless1 and no longer a dragon71 and so on4 ,secondly1 it is necessary that the actual appearance of the heavens1 with reference to the position of the pole in ,homer's time should be indicated4 ,for my present purpose1 it is not necessary that we should know the exact date at which the most ancient of the zodiac-temples were constructed 7or to which they were made to correspond74 ,there are good reasons1 though this is not the proper place for dwelling upon them1 for supposing that the great epoch of reference amongst ancient astronomers preceded the ,christian era by about #bbjj years4 ,be this as it may1 any epoch between the date named and the probable date at which ,homer flourished--say nine or ten centuries before the ,christian era--will serve equally well for my present purpose4 ,now if the effects of equinoctial precession be traced back to such a date1 we are led to notice two singular and not uninteresting circumstances4 ,first1 the pole of the heavens fell in the central part of the great constellation ,draco2 and1 secondly1 the equator fell along the length of the great sea-serpent ,hydra1 in one part of its course1 and elsewhere to the north of all the ancient aquatic constellations1#ba save that one-half of the northernmost fish 7of the zodiac pair7 lay north of the equator4 ,thus1 if a celestial sphere were constructed with the equator in a horizontal position1 the ,dragon would be at the summit1 ,hydra would be extended horizontally along the equator--but with his head and neck reared above that circle--and ,argo1 ,cetus1 ,capricornus1 ,piscis ,australis1 and ,pisces--save one-half of the northernmost--would lie below the equator4 ,it may also be mentioned that all the bird-constellations were then1 as now1 clustered together not far from the equator--,cygnus 7the farthest from the equator7 being ten degrees or so nearer to that circle than at present4 ,now let us turn to the two #8shields1' and see whether there is anything to connect them with zodiac-temples1 or to remind us of the relations exhibited above4 ,to commence with the #8,shield of ,achilles1' the opening lines inform us that the shield showed-- ,the starry lights that heav'n's high convex crown'd1 ,the ,pleiads1 ,hyads1 with the northern team1 ,and great ,orion's more refulgent beam4 ,and here1 in ,achilles' shield1 the list of constellations closes2 but it is remarkable that in the #8,shield of ,hercules1' while the above lines are wanting1 we find lines which clearly point to other constellations4 ,remembering what has just been stated about ,draco1 it seems at the least a singular coincidence that we should find the centre or boss of the shield occupied by a dragon3-- ,the scaly horror of a dragon1 coil'd ,full in the central field1 unspeakable1 ,with eyes oblique retorted1 that aslant ,shot gleaming flame4#bb--;,elton's ,translation4 ,we seem1 also1 to find a reference to the above-named relations of the aquatic constellations1 and specially to the constellation ,pisces3-- ,in the midst1 ,full many dolphins chased the fry1 and show'd ,as though they swam the waters1 to and fro ,darting tumultuous3 two#bc of silver scale ,panting above the wave4 ,for we learn from both #8shields' that the waves of ocean were figured in a position corresponding with the above-mentioned position of the celestial equator1 beneath which--that is1 in the ocean1 on our assumption--the aquatic constellations were figured4 ,the description of the ocean in the #8,shield of ,hercules' contains also some lines1 in which we seem to see a reference to the bird-constellations close above the equator3-- ,rounding the utmost verge the ocean flow'd ,as in full swell of waters1 and the shield ,all variegated with whole circle bound4 ,swans of high-hovering wing there clamour'd shrill1 ,who also skimm'd the breasted surge with plume ,innumerous2 near them fishes midst the waves ,frolick'd in wanton bounds4 ,in the #8,shield of ,achilles' no mention is made of ,perseus1 but in the #8,shield of ,hercules' this well-known constellation seems described in the lines-- ,there was the knight of fair-hair'd ,danae born1 ,perseus2 nor yet the buckler with his feet ,touch'd nor yet distant hover'd1 strange to see1 ,for nowhere on the surface of the shield ,he rested2 so the crippled artist-god ,illustrious fram'd him with his hands in gold4 ,bound to his feet were sandals wing'd2 a sword ,of brass1 with hilt of sable ebony1 ,hung round him from the shoulders by a thong4 4 4 4 4 4 4 4 4 ,the visage grim ,of monstrous ,gorgon all his back o'erspread2 4 4 4 4 4 4 4 4 the dreadful helm ,of ,pluto clasp'd the temples of the prince4 ,i think that one may recognise a reference to the twins ,castor and ,pollux 7the wrestler and boxer of mythology7 in the words-- ,but in another part ,were men who wrestled1 or in gymnic fight ,wielded the cestus4 ,orion is not mentioned by name in the #8,shield of ,hercules1' as in the other2 but ,orion1 ,lepus1 and the two dogs seem referred to3-- ,elsewhere men of chase ,were taking the fleet hares2 two keen-toothed dogs ,hounded beside2 these ardent in pursuit1 ,those with like ardour doubling in their flight4 ,in each #8shield' we find a reference to the operations of the year--hunting and pasturing1 sowing1 ploughing1 and harvesting4 ,it is hardly necessary to point out the connection between these operations and astronomical relations4 ,that this connection was fully recognised in ancient times is shown in the #8,works and ,days' of ,hesiod4 ,we find also in ,egyptian zodiacs clear evidence that these operations1 as well as astronomical symbols or constellations1 were pictured in sculptured domes4 ,the judicial1 military1 and other proceedings described in the #8,shield of ,achilles' were also supposed by the ancients to have been influenced by the courses of the stars4 ,if there were no evidence that ancient celestial spheres presented the constellations above referred to1 ,i might be disposed to attach less weight to the coincidences here presented2 but the #8,phenomena' of ,aratus affords sufficient testimony on this point4 ,in the first place1 that work is of great antiquity1 since ,aratus flourished two centuries and a half before the ,christian era2 but it is well known that ,aratus did not describe the results of his own observations4 ,the positions of the constellations1 as recorded by him1 accord neither with the date at which he wrote nor with the latitude in which he lived4 ,it is generally assumed--chiefly on the authority of ,hipparchus--that ,aratus borrowed his knowledge of astronomy from the sphere of ,eudoxus2 but we must go much farther back even than the date of ,eudoxus1 before we can find any correspondence between the appearance of the heavens and the description given by ,aratus4 ,thus we may very fairly assume that the origin of the constellations 7as distinguished from their association with certain circles of the celestial sphere7 may be placed at a date preceding1 perhaps by many generations1 that at which ,homer flourished4 ,indeed1 there have not been wanting those who find in the ancient constellations the record of the early history of man4 ,according to their views1 ,orion is ,nimrod--the #8,giant1' as the ,arabic name of the constellation implies--the mighty hunter1 as the dogs and hare beside him signify4 ,the ,centaur bearing a victim towards the altar is ,noah2 ,argo1 the stern of a ship1 is the ark1 as of old it might be seen on ,mount ,ararat4 ,corvus is the crow sent forth by ,noah1 and the bird is placed on ,hydra's back to show that there was no land on which it could set its foot4 ,the figure now called ,hercules1 but of old ,engonasin1 or the kneeler1 and described by ,aratus as #8a man doomed to labour1' is ,adam4 ,his left foot treads on the dragon's head1 in token of the saying1 #8,it shall bruise thy head2 #8and ,serpentarius1 or the serpent-bearer1 is the promised seed4 ,of course1 if we accept these views1 we have no difficulty in understanding that a poet so ancient as ,homer should refer to the constellations which still appear upon celestial spheres4 ,and1 in any case1 the mere question of antiquity presents1 as we have already shown1 little difficulty4 ,but there is one difficulty1 a notice of which must close this paper1 already carried far beyond the limits ,i had proposed to myself3--,it may be thought remarkable that heroes of ,greek mythology1 as ,perseus and ,orion1 should be placed by ,homer1 or even by ,aratus1 in spheres which are undoubtedly of eastern origin4 ,now it may be remarked1 first1 of ,homer1 that many acute critics consider the whole story of the #8,iliad' to be1 in reality1 merely an adaptation of an eastern narrative to ,greek scenes and names4 ,it is pointed out1 that1 whereas the ,catalogue in ,book ,,ii4 reckons upwards of #ajj1jjj men1 only #aj1jjj fought at ,marathon2 and1 whereas there are counted no less than #a1bjj ships in the ,catalogue1 there were but #bga at ,artemisium1 and at ,salamis but #cgh4 ,however this may be1 we have the distinct evidence of ,herodotus that the ,greek mythology was derived originally from foreign sources4 ,he says1 #8,all the names of the gods in ,greece were brought from ,egypt1' an opinion in which ,diodorus and other eminent authorities concur4 ,but it is the opinion of acute modern critics that we must go beyond ,egyptian--to ,assyrian1 or ,indian1 perhaps even to ,hebrew sources--for the origin of ,greek mythology4 ,layard has ascribed to ,niebuhr the following significant remarks3 #8,there is a want in ,grecian art which neither ,i1 nor any man now alive1 can supply4 ,there is not enough in ,egypt to account for the peculiar art and the peculiar mythology which we find in ,greece4 ,that the ,egyptians did not originate it ,i am convinced1 though neither ,i1 nor any man now alive1 can say who were the originators4 ,but the time will come when1 on the borders of the ,tigris and ,euphrates1 those who come after me will live to see the origin of ,grecian art and ,grecian mythology4' 7,from ,the ,student1 ,june #ahfh47 ,,london3 ,,printed ,,by ,,spottiswoode ,,and ,,co41 ,,new-,,street ,,square ,,and ,,parliament ,,street ,,footnotes3 #ai ,another well-known instance1 where #8,patroclus1 sent in hot haste for news by a man of the most fiery impatience1 is button-held by ,nestor1 and though he has no time to sit down1 yet is obliged to endure a speech of #aeb lines1' is accounted for by ,gladstone in a different manner4 #bj ,besides ,homer's reference1 both in the #8,iliad' and #8,odyssey1' to poetic recitations at festivals1 there is the well-known invocation in ,book ,,ii4 ,to what purpose would the mere writer of poetry pray for an increase of his physical powers8 ,nothing could be more proper1 says ,gladstone1 if ,homer were about to recite2 nothing less proper if he were engaged on a written poem4 #ba ,we may exclude ,delphinus as probably later than ,homer's time1 though mentioned by ,aratus4 #bb ,compare the description of the constellation ,draco by ,aratus3-- ,swol'n is his neck--eyes charg'd with sparkling fire ,his crested head illume4 ,as if in ire ,to ,helice he turns his foaming jaw ,and darts his tongue1 barb'd with a blazing star4 --,lamb's ,translation4 #bc ,it is scarcely necessary to remark that1 no importance is to be attached to the numerical relations in this and other passages4 ,in the original work describing a zodiac-dome1 the exact number of constellations representing fishes1 dogs1 or the like1 would of course be mentioned2 but any changes necessary to ,homer's purpose in describing a shield would unhesitatingly have been introduced by him subsequently4 ,it is singular1 however1 that we should have here1 and in the passage quoted farther on as referring to ,orion and the ,dogs1 the number two specially mentioned4 ,the latter instance is the more remarkable inasmuch as the mention of men and hares would lead one to expect that more than two dogs would be introduced4 ,i would suggest as a sufficient reason for this peculiarity that the verbal alterations necessary to pluralise some of the objects in the dome would be more easily effected than those necessary to undualise others4 ,,the #8,,knowledge' ,,library4 ,,edited ,,by ,,richard ,a4 ,,proctor4 ,,science ,,byways4 ,a ,series of ,familiar ,dissertations on ,life in ,other ,worlds4 ,by ,,richard ,a4 ,,proctor4 ,crown #hvo4 #fs4 ,the ,,poetry of ,,astronomy4 ,a ,series of ,familiar ,essays on the ,heavenly ,bodies4 ,by ,,richard ,a4 ,,proctor4 ,crown #hvo4 #fs4 ,,nature ,,studies4 ,reprinted from #8,knowledge4' ,by ,,grant ,,allen1 ,,andrew ,,wilson1 ,,thomas ,,foster1 ,,edward ,,clodd1 and ,,richard ,a4 ,,proctor4 ,crown #hvo4 #fs4 ,,leisure ,,readings4 ,reprinted from #8,knowledge4' ,by ,,edward ,,clodd1 ,,andrew ,,wilson1 ,,thomas ,,foster1 ,a4 ,c4 ,,runyard1 and ,,richard ,a4 ,,proctor4 ,crown #hvo4 #fs4 ,the ,,stars in their ,,seasons4 ,an ,easy ,guide to a ,knowledge of the ,star ,groups1 in ,twelve ,large ,maps4 ,by ,,richard ,a4 ,,proctor4 ,imperial #hvo4 #es4 ,london3 ,,longmans1 ,,green1 ,,co4 ,,works ,,by ,r4 ,a4 ,,proctor ,the ,,sun2 ,ruler1 ,light1 ,fire1 and ,life of the ,planetary ,system4 ,by ,r4 ,a4 ,,proctor1 ,b4,a4 ,with ,plates and ,woodcuts4 ,crown #hvo4 #ads4 ,the ,,orbs ,,around ,,us2 a ,series of ,essays on the ,moon and ,planets1 ,meteors and ,comets1 the ,sun and ,coloured ,pairs of ,suns4 ,with ,chart and ,diagrams4 ,crown #hvo4 #gs4 #f;d4 ,,other ,,worlds than ,,ours2 the ,plurality of ,worlds ,studied under the ,light of ,recent ,scientific ,researches4 ,with #ad ,illustrations4 ,crown #hvo4 #ajs4 #f;d4 ,the ,,moon3 her ,motions1 ,aspects1 ,scenery1 and ,physical ,condition4 ,with ,plates1 ,charts1 ,woodcuts1 and ,lunar ,photographs4 ,crown #hvo4 #ajs4 #f;d4 ,,universe of ,,stars2 ,presenting ,researches into and ,new ,views respecting the ,constitution of the ,heavens4 ,with #bb ,charts and #bb ,diagrams4 #hvo4 #ajs4 #f;d4 ,,light ,,science for ,,leisure ,,hours2 ,familiar ,essays on ,scientific ,subjects1 ,natural ,phenomena1 c4 #c vols4 crown #hvo4 #gs4 #f;d4 each4 ,,new ,,star ,,atlas for the ,library1 the ,school1 and the ,observatory1 in #ab ,circular ,maps 7with #b ,index ,plates74 ,crown #hvo4 #es4 ,,larger ,,star ,,atlas for the ,library1 in ,twelve ,circular ,maps1 with ,introduction and #b ,index ,plates4 ,folio1 #aes41 or ,maps only1 #abs4 #f;d4 ,,essays on ,,astronomy4 ,a ,series of ,papers on ,planets and ,meteors1 the ,sun and ,sun-surrounding ,space1 ,stars and ,star ,cloudlets4 ,with #aj ,plates and #bd ,woodcuts4 #hvo4 #abs4 ,,transits of ,,venus2 a ,popular ,account of ,past and ,coming ,transits1 from the ,first ,observed by ,horrocks in #afci to the ,transit of #bjab4 ,with #bj ,lithographic ,plates 7#ab ,coloured7 and #ch ,illustrations engraved on ,wood4 #hvo4 #hs4 #f;d4 ,,studies of ,,venus-,,transits2 an ,investigation of the ,circumstances of the ,transits of ,venus in #ahgd and #ahhb4 ,with #g ,diagrams and #aj ,plates4 #hvo4 #es4 ,,pleasant ,,ways in ,,science1 with numerous ,illustrations4 ,crown #hvo4 #fs4 ,,myths and ,,marvels of ,,astronomy1 with numerous ,illustrations4 ,crown #hvo4 #fs4 ,london3 ,,longmans1 ,,green1 ,,co4 99 99 99 99 99 ,transcriber's ,notes ,obvious typographical errors have been silently corrected4 ,variations in hyphenation and all other spelling and punctuation remain unchanged4 ,italics are represented thus italic4