let us say—150 pounds. If this weight was borne on one squareinch, the pressure would be ten atmospheres. But the skater restshis weight, in fact, upon an area of one-fiftieth of an inch. Thepressure is, therefore, fifty times as great. The ice issubjected to a pressure of 500 atmospheres. This lowers themelting point to -3.75° C. Hence, on a day when the ice is atthis temperature, the skate will sink in the ice till the weightof the skater is concentrated as we have assumed. His skate cansink no further, for any lesser concentration of the pressurewill not bring the melting point below the prevailingtemperature. We can calculate the theoretical bite for any stateof the ice. If the ice is colder the bite will not be so deep. Ifthe temperature was twice as far below zero, then the area overwhich the skater's weight will be distributed, when the skate haspenetrated its maximum depth, will be only half the former area,and the pressure will be one thousand atmospheres.
An important consideration arises from the fact that under thevery extreme edge of the skate the pressure is indefinitelygreat. For this involves that there will always be some bite,however cold the ice may be. That is, the narrow strip of icewhich first receives the skater's weight must partially liquefyhowever cold the ice.
It must have happened to many here to be on ice which was toocold to skate on with comfort. The
280
skater in this case speaks of the ice as too hard. In theEngadine, the ice on the large lakes gets so cold that skaterscomplain of this. On the rinks, which are chiefly used there, theice is frequently renewed by flooding with water at the close ofthe day. It thus never gets so very cold as on the lakes. I havebeen on ice in North France, which, in the early morning, was toohard to afford sufficient bite for comfort. The cause of this iseasily understood from what we have been considering.
We may now return to the experimental results which we obtainedearly in the lecture. The heavy weights slip off the ice at a lowangle because just at the points of contact with the ice thelatter melts, and they, in fact, slip not on ice but on water.The light weights on cold, dry ice do not lower the melting pointbelow the temperature of the ice, _i.e._ below -10° C., and sothey slip on dry ice. They therefore give us the true coefficientof friction of metal on ice.
This subject has, more recently been investigated by H. Morphy,of Trinity College, Dublin. The refinement of a closed vessel atuniform temperature, in which the ice is formed and theexperiment carried out, is introduced. Thermocouples give thetemperatures, not only of the ice but of the aluminium sleighwhich slips upon it under various loads. In this way we may becertain that the metal runners are truly at the temperature ofthe ice. I now quote from Morphy's paper
281
"The angle of friction was found to remain constant until acertain stage of the loading, when it suddenly fell to about halfof its original value. It then remained constant for furtherincreases in the load.
"These results, which confirmed those obtained previously withless satisfactory apparatus, are shown in the table below. In thefirst column is shown the load, _i.e._ the weight of sleigh +weight of shot added. In the second and third columns are shown,respectively, the coefficient and angle of friction, whilst thefourth gives the temperature of the ice as determined from thegalvanometer deflexions.
Load. Tan y. y. Temp.
5.68 grams. 0.36±.01 20°±30' -5.65° C.10.39 -5.65°11.96 -5.75°12.74 -5.60°13.53 -5.65°14.31 -5.65°15.10 grams. 0.17±.01 9°.30'±30' -5.60°16.67 -5.55°19.81 -5.60°24.52 -5.60°5.68 grams. 0.36±.01 20°±30' -5.60°
"These experiments were repeated on another occasion with the sameresult and similar results had been obtained with differentapparatus.
"As a result of the investigation the following points areclearly shown:—
282
"(1) The coefficient of friction for ice at constant temperaturemay have either of two constant values according to the pressureper unit surface of contact.
"(2) For small pressures, and up to a certain well defined limitof pressure, the coefficient is fairly large, having the value0.36±.01 in the case investigated.
"(3) For pressures greater than the above limit the coefficientis relatively small, having the value 0.17±.01 in the caseinvestigated."
It will be seen that Morphy's results are similar to thosearrived at in the first experimental consideration of oursubject; but from the manner in which the experiments have beencarried out, they are more accurate and reliable.
A great deal more might be said about skating, and the alliedsports of tobogganing, sleighing, curling, ice yachting, andlast, but by no means least, sliding—that unpretentious pastimeof the million. Happy the boy who has nails in his boots whenJack-Frost appears in his white garment, and congeals theneighbouring pond. But I must turn away at the threshold of thehumorous aspect of my subject (for the victim of the street"slide" owes his injured dignity to the abstruse laws we havebeen discussing) and pass to other and graver subjects intimatelyconnected with skating.
James Thomson pointed out that if we apply compressional stressto an ice crystal contained in a vessel
283
which also contains other ice crystals, and water at 0° C., thenthe stressed crystal will melt and become water, but itscounterpart or equivalent quantity of ice will reappear elsewherein the vessel. This is, obviously, but a deduction from theprinciples we have been examining. The phenomenon is commonlycalled "regelation." I have already made the usual regelationexperiment before you when I compressed broken ice in this mould.The result was a clear, hard and almost flawless lens of ice. Nowin this operation we must figure to ourselves the pieces of icewhen pressed against one another melting away where compressed,and the water produced escaping into the spaces between thefragments, and there solidifying in virtue of its temperaturebeing below the freezing point of unstressed water. The finalresult is the uniform lens of ice. The same process goes on in aless perfect manner when you make—or shall I better say—when youmade snowballs.
We now come to theories of glacier motion; of which there aretwo. The one refers it mainly to regelation; the other to a realviscosity of the ice.
The late J. C. M'Connel established the fact that ice possessesviscosity; that is, it will slowly yield and change its shapeunder long continued stresses. His observations, indeed, raise adifficulty in applying this viscosity to explain glacier motion,for he showed that an ice crystal is only viscous in a certainstructural
284
direction. A complex mixture of crystals such, as we know glacierice to be, ought, we would imagine, to display a nett orresultant rigidity. A mass of glacier ice when distorted byapplication of a force must, however, undergo precisely thetransformations which took place in forming the lens from thefragments of ice. In fact, regelation will confer upon it all theappearance of viscosity.
Let us picture to ourselves a glacier pressing its enormous massdown a Swiss valley. At any point suppose it to be hindered inits downward path by a rocky obstacle. At that point the iceturns to water just as it does beneath the skate. The cold waterescapes and solidifies elsewhere. But note this, only where thereis freedom from pressure. In escaping, it carries away its latentheat of liquefaction, and this we must assume, is lost to theregion of ice lately under pressure. This region will, however,again warm up by conduction of heat from the surrounding ice, orby the circulation of water from the suxface. Meanwhile, thepressure at that point has been relieved. The mechanicalresistance is transferred elsewhere. At this new point there isagain melting and relief of pressure. In this manner the glaciermay be supposed to move down. There is continual flux ofconducted heat and converted latent heat, hither and thither, toand from the points of resistance. The final motion of the wholemass is necessarily slow; a few feet in the day or, in winter,
285
even only a few inches. And as we might expect, perfect silenceattends the downward slipping of the gigantic mass. The motionis, I believe, sufficiently explained as a skating motion. Theskate is, however, fixed, the ice moves. The great AletschGlacier collects its snows among the highest summits of theOberland. Thence, the consolidated ice makes its way into theRhone Valley, travelling a distance of some 20 miles. The ice nowmelting into the youthful Rhone fell upon the Monch, the Jungfrauor the Eiger in the days when Elizabeth ruled in England andShakespeare lived.
The ice-fall is a common sight on the glacier. In great lumps andbroken pinnacles it topples over some rocky obstacle and fallsshattered on to the glacier below. But a little further down thewound is healed again, and regelation has restored the smoothsurface of the glacier. All such phenomena are explained on JamesThomson's exposition of the behaviour of a substance whichexpands on passing from the liquid to the solid state.
We thus have arrived at very far-reaching considerations arisingout of skating and its science. The tendency for snow toaccumulate on the highest regions of the Earth depends onprinciples which we cannot stop to consider. We know it collectsabove a certain level even at the Equator. We may consider, then,that but for the operation of the laws which James Thomsonbrought to light, and which his illustrious brother,
286
Lord Kelvin, made manifest, the uplands of the Earth could nothave freed themselves of the burthen of ice. The geologicalhistory of the Earth must have been profoundly modified. Thehigher levels must have been depressed; the general level of theocean relatively to the land thereby raised, and, it is evenpossible, that such a mean level might have been attained aswould result in general submergence.
During the last great glacial period, we may say the fate of theworld hung on the operation of those laws which have concerned usthroughout this lecture. It is believed the ice was piled up to aheight of some 6,000 feet over the region of Scandinavia. Underthe influence of the pressure and fusion at points of resistance,the accumulation was stayed, and it flowed southwards theaccumulation was stayed, and it flowed southwards over NorthernEurope. The Highlands of Scotland were covered with, perhaps,three or four thousand feet of ice. Ireland was covered fromnorth to south, and mighty ice-bergs floated from our western andsouthern shores.
The transported or erratic stones, often of great size, which arefound in many parts of Ireland, are records of these long pastevents: events which happened before Man, as a rational being,appeared upon the Earth.
287
A SPECULATION AS TO A PREMATERIAL UNIVERSE[1]
"And therefore...these things likewise had a birth; for thingswhich are of mortal body could not for an infinite time back...have been able to set at naught the puissant strength ofimmeasurable age."—LUCRETIUS, _De Rerum Natura._
"O fearful meditation! Where, alack! Shall Time's best jewelfrom Time's chest lie hid?" —SHAKESPEARE.
IN the material universe we find presented to our senses aphysical development continually progressing, extending to all,even the most minute, material configurations. Some fundamentaldistinctions existing between this development as apparent in theorganic and the inorganic systems of the present day are referredto elsewhere in this volume.[2] In the present essay, thesesystems as having a common origin and common ending, are mergedin the same consideration as to the nature of the origin ofmaterial systems in general. This present essay is occupied bythe consideration of the necessity of limiting materialinteractions in past time. The speculation originated in thedifficulties which present themselves when we ascribe to theseinteractions infinite duration in the past. These difficultiesfirst claim our consideration.
[1] Proc. Royal Dublin Soc., vol. vii., Part V, 1892.
[2] _The Abundance of Life._
288
Accepting the hypothesis of Kant and Laplace in its widestextension, we are referred to a primitive condition of widematerial diffusion, and necessarily too of material instability.The hypothesis is, in fact, based upon this material instability.We may pursue the sequence of events assumed in this hypothesisinto the future, and into the past.
In the future we find finality to progress clearly indicated. Thehypothesis points to a time when there will be no moreprogressive change but a mere sequence of unfruitful events, suchas the eternal uniform motion of a mass of matter no longergaining or losing heat in an ether possessed of a uniformdistribution of energy in all its parts. Or, again, if the etherabsorb the energy of material motion, this vast and darkaggregation eternally poised and at rest within it. The action istransferred to the subtle parts of the ether which suffer none ofthe energy to degrade. This is, physically, a thinkable future.Our minds suggest no change, and demand none. More than this,change is unthinkable according to our present ideas of energy.Of progress there is an end.
This finality _â parte post_ is instructive. Abstractconsiderations, based on geometrical or analytical illustrations,question the finiteness of some physical developments. Thus oursun may require eternal time to attain the temperature of theether around it, the approach to this condition being assumed tobe asymptotic in
289
character. But consider the legitimate _reductio ad absurdum_ ofan ember raked from a fire 1000 years ago. Is it not yet cooleddown to the constant temperature of its surroundings? And we mayevidently increase the time a million-fold if we please. Itappears as if we must regard eternity as outliving everyprogressive change, For there is no convergence or enfeeblementof time. The ever-flowing present moves no differently for theoccurrence of the mightiest or the most insignificant events. Andeven if we say that time is only the attendant upon events, yetthis attendant waits patiently for the end, however longdeferred.
Does the essentially material hypothesis of Kant and Laplaceaccount for an infinite past as thinkably as it accounts for theinfinite future? As this hypothesis is based upon materialinstability the question resolves itself into this:— Is theassumption of an infinitely prolonged past instability a probableor possible account of the past? There are, it appears to me,great difficulties involved in accepting the hypothesis ofinfinitely prolonged material instability. I will refer here tothree principal objections. The first may be called ametaphysical objection; the second is partly metaphysical andpartly physical, the third may be considered a physicalobjection, as it is involved directly in the phenomena presentedby our universe.
The metaphysical objection must have presented itself to everyone who has considered the question. It may
290
be put thus:—If present events are merely one stage in aninfinite progress, why is not the present stage long ago passedover? We are evidently at liberty to push back any stage ofprogress to as remote a period as we like by putting back firstthe one before this and next the stage preceding this, and so on,for, by hypothesis, there is no beginning to the progress.
Thus, the sum of passing events constituting the present universeshould long ago have been accomplished and passed away. If weconsider alternative hypotheses not involving this difficulty, weare at once struck by the fact that the future of materialdevelopment is free of the objection. For the eternity ofunprogressive events involved in the future on Kant's hypothesis,is not only thinkable, but any change is, as observed,irreconcilable with our ideas of energy. As in the future so inthe past we look to a cessation to progress. But as we believethe activity of the present universe must in some form haveexisted all along, the only refuge in the past is to imagine anactive but unprogressive eternity, the unprogressive activity atsome period becoming a progressive activity—that progressiveactivity of which we are spectators. To the unprogressiveactivity there was no beginning; in fact, beginning is asunthinkable and uncalled for to the unprogressive activity of thepast as ending is to the unprogressive activity of the future,when all developmental actions shall have ceased. There is nobeginning or ending to the activity of the universe.
291
There is beginning and ending to present progressive activity.Looking through the realm of nature we seek beginning and ending,but "passing through nature to eternity" we find neither. Bothare justified; the questioning of the ancient poet regarding thepast, and of the modern regarding the future, quoted at the headof this essay.
The next objection, which is in part metaphysical, is founded onthe difficulty of ascribing any ultimate reality or potency toforces diminishing through eternal time. Thus, against theassumption that our universe is the result of materialaggregation progressing over eternal time, which involves theprimitive infinite separation of the particles, we may ask, whatforce can have acted between particles sundered by infinitedistance? The gravitational force falling off as the square ofthe distance, must vanish at infinity if we mean what we say whenwe ascribe infinite separation to them. Their condition is thenone of neutral stability, a finite movement of the particlesneither increasing nor diminishing interaction. They had thenremained eternally in their separated condition, there being nocause to render such condition finite. The difficulty involvedhere appears to me of the same nature as the difficulty ofascribing any residual heat to the sun after eternal time haselapsed. In both cases we are bound to prolong the time, from ourvery idea of time, till progress is no more, when in the one casewe can imagine no mutual approximation of the
292
particles, in the other no further cooling of the body. However,I will riot dwell further upon this objection, as it does not, Ibelieve, present itself with equal force to every mind. A reasonless open to dispute, as being less subjective, against theaggregation of infinitely remote particles as the origin of ouruniverse, is contained in the physical objection.
In this objection we consider that the appearance presented byour universe negatives the hypothesis of infinitely prolongedaggregation. We base this negation upon the appearance ofsimultaneity ~ presented by the heavens, contending that thissimultaneity is contrary to what we would expect to find in thecase of particles gathered from infinitely remote distances.Whether these particles were endowed with relative motions or notis unimportant to the consideration. In what respects do thephenomena of our universe present the appearance of simultaneousphenomena? We must remember that the suns in space are as fireswhich brighten only for a moment and are then extinguished. It isin this sense we must regard the longest burning of the stars.Whether just lit or just expiring counts little in eternity. Thelight and heat of the star is being absorbed by the ether ofspace as effectually and rapidly as the ocean swallows the ripplefrom the wings of an expiring insect. Sir William Herschel saysof the galaxy of the milky way:— "We do not know the rate ofprogress of this mysterious chronometer, but it is neverthelesscertain that it cannot
293
last for ever, and its past duration cannot be infinite." We donot know, indeed, the rate of progress of the chronometer, but ifthe dial be one divided into eternal durations the consummationof any finite physical change represents such a movement of thehand as is accomplished in a single vibration of the balancewheel.
Hence we must regard the hosts of glittering stars as aconflagration that has been simultaneously lighted up in theheavens. The enormous (to our ideas) thermal energy of the starsresembles the scintillation of iron dust in a jar of oxygen whena pinch of the dust is thrown in. Although some particles beburnt up before others become alight, and some linger yet alittle longer than the others, in our day's work thescintillation of the iron dust is the work of a single instant,and so in the long night of eternity the scintillation of themightiest suns of space is over in a moment. A little longer,indeed, in duration than the life which stirs a moment inresponse to the diffusion of the energy, but only very little. Somust an Eternal Being regard the scintillation of the stars andthe periodic vibration of life in our geological time and themost enduring efforts of thought. The latter indeed are no morelasting than
"... the labour of ants In the light of a million million ofsuns."
But the myriad suns themselves, with their generations, are themomentary gleam of lights for ever after extinguished.
294
Again, science suggests that the present process of materialaggregation is not finished, and possibly will only be when itprevails universally. Hence the very distribution of the stars,as we observe them, as isolated aggregations, indicates adevelopment which in the infinite duration must be regarded asequally advanced in all parts of stellar space and essentially asimultaneous phenomenon. For were we spectators of a system inwhich any very great difference of age prevailed, this very greatdifference would be attended by some such appearance as thefollowing:—
The aupearance of but one star, other generations being longextinct or no others yet come into being; or, perhaps, a faintnebulous wreath of aggregating matter somewhere solitary in theheavens; or no sign of matter beyond our system, either becauseungathered or long passed away into darkness.[1]
Some such appearances were to be expected had the aggregation ofmatter depended solely on chance encounters of particlesscattered through infinite space.
For as, by hypothesis, the aggregation occupies an infinite timein consummation it is nearly a certainty that each particleencountered after immeasurable time, and then for the first timeendowed with actual gravitational potential energy, would havelong expended this energy
[1] It is interesting to reflect upon the effect which an entireabsence of luminaries outside our solar system would have hadupon the views of our philosophers and upon our outlook on life.
295
before another particle was gathered. But the fact that so manyfires which we know to be of brief duration are scattered througha region of space, and the fact of a configuration which webelieve to be a transitory ore, suggest their simultaneousaggregation here and there. And in the nebulous wreaths situatedamidst the stars there is evidence that these actually originatedwhere they now are, for in such no relative motion, I believe,has as yet been detected by the spectroscope. All this, too, isin keeping with the nebular hypothesis of Kant and Laplace solong as this does not assume a primitive infinite dispersion ofmatter, but the gathering of matter from finite distances firstinto nebulous patches which aggregating with each other havegiven rise to our system of stars. But if we extend thishypothesis throughout an infinite past by the supposition ofaggregation of infinitely remote particles we replace thesimultaneous approach required in order to accotnt for thesimultaneous phenomena visible in the heavens, by a succession ofaggregative events, by hypothesis at intervals of nearly infiniteduration, when the events of the universe had consisted of fitfulgleams lighted after eternities of time and extinguished for yetother eternities.
Finally, if we seek to replace the eternal instability involvedin Kant's hypothesis when extended over an infinite past, by anyhypothesis of material stability, we at once find ourselves inthe difficulty that from the known properties of matter suchstability must have been
296
permanent if ever existent, which is contrary to fact. Thus thekinetic inertia expressed in Newton's first law of motion mightwell be supposed to secure equilibrium with material attraction,but if primevally diffused matter had ever thus been held inequilibrium it must have remained so, or it was maintained soimperfectly, which brings us back to endless evolution.
On these grounds I contend that the present gravitationalproperties of matter cannot be supposed to have acted for allpast duration. Universal equilibrium of gravitating particleswould have been indestructible by internal causes. Perpetualinstability or evolution is alike unthinkable and contrary to thephenomena of the universe of which we are cognisant. We thereforeturn from gravitating matter as affording no rational account ofthe past. We do so of necessity, however much we feel ourignorance of the nature of the unknown actions to which we haverecourse.
A prematerial condition of the universe was, we assume, acondition in which uniformity as regards the average distributionof energy in space prevailed, but neterogeneity and instabilitywere possible. The realization of that possibility was thebeginning we seek, and we today are witnesses of the train ofevents involved in the breakdown of an eternal past equilibrium.We are witnesses on this hypothesis, of a catastrophe possiblyconfined to certain regions of space, but which is, to themotions and configurations concerned, absolutely unique,reversible to
297
its former condition of potential by no process of which we canhave any conception.
Our speculation is that we, as spectators of evolution, arewitnessing the interaction of forces which have not always beenacting. A prematerial state of the universe was one of unfruitfulmotions, that is, motions unattended by progressing changes, inour region of the ether. How extended we cannot say; the natureof the motions we know not; but the kinetic entities differedfrom matter in the one important particular of not possessinggravitational attraction. Such kinetic configurations we cannotconsider to be matter. It was _possible_ to construct matter bytheir summation or linkage as the configuration of the crystal ispossible in the clear supersaturated liquid.
Duration in an ether filled with such motions would pass in asuccession of mere unfruitful events; as duration, we mayimagine, even now passes in parts of the ether similar to ourown. An endless (it may be) succession of unprogressive,fruitless events. But at one moment in the infinite duration therequisite configuration of the elementary motions is attained;solely by the one chance disposition the stability of all mustgo, spreading from the fateful point.
Possibly the material segregation was confined to one part ofspace, the elementary motions condensing upon transformation, andso impoverishing the ether around till the action ceased. Againin the same sense as the
298
stars are simultaneous, so also they may be regarded as uniformin size, for the difference in magnitude might have been anythingwe please to imagine, if at the same time we ascribe sufficientdistance sundering great and small. So, too;, will a dilutesolution of acetate of soda build a crystal at one point, and theimpoverishment of the medium checking the growth in this region,another centre will begin at the furthest extremities of thefirst crystal till the liquid is filled with loose featheryaggregations comparable in size with one another. In a similarway the crystallizing out of matter may have given rise, not to auniform nebula in space, but to detached nebula, approximately ofequal mass, from which ultimately were formed the stars.
That an all-knowing Being might have foretold the ultimate eventat any preceding period by observing the motions of the partsthen occurring, and reasoning as to the train of consequencesarising from these nations, is supposable. But considerationsarising from this involve no difficulty in ascribing to thisprematerial train of events infinite duration. For progress thereis none, and we can quite as easily conceive of some part ofspace where the same Infinite Intelligence, contemplating asimilar train of unfruitful motions, finds that at no time in thefuture will the equilibrium be disturbed. But where evolution isprogressing this is no longer conceivable, as being contradictoryto the very idea of progressive development. In this caseInfinite Intelligence
299
_necessarily_ finds, as the result of his contemplation, theaggregation of matter, and the consequences arising therefrom.
The negation of so primary a material property as gravitation tothese primitive motions of (or in) the ether, probably involvesthe negation of many properties we find associated with matter.Possibly the quality of inertia, equally primary, is involvedwith that of gravitation, and we may suppose that these twoproperties so intimately associated in determining the motions ofbodies in space were conferred upon the primitive motions ascrystallographic attraction and rigidity are first conferred uponthe solid growing from the supersaturated liquid. But in somedegree less speculative is the supposition that the new order ofmotions involved the transformation of much energy into the formof heat vibrations; so that the newly generated matter, like thenewly formed crystal, began its existence in a medium richly fedwith thermal radiant energy. We may consider that the thermalconditions were such as would account for a primitivedissociation of the elements. And, again, we recall how thephysicist finds his estimate of the energy involved in meregravitational aggregation inadequate to afford explanation ofpast solar heat. It is supposable, on such a hypothesis as wehave been dwelling on, that the entire subsequent gravitationalcondensation and conversion of material potential energy, datingfrom the first formation of matter to the stage of starformation
300
may be insignificant in amount compared with the conversion ofetherial energy attending the crystallizing out of matter fromthe primitive motions. And thus possibly the conditions thenobtaining involved a progressively increasing complexity ofmaterial structure the genesis of the elements, from aninfra-hydrogen possessing the simplest material configuration,resulting ultimately in such self-luminous nebula as we yet seein the heavens.
The late James Croll, in his _Stellar Evolution_, finds objectionsto an eternal evolution, one of which is similar to the"metaphysical" objection urged in this paper. His way out of thedifficulty is in the speculation that our stellar systemoriginated by the collision of two masses endowed with relativemotion, eternal in past duration, their meeting ushering in thedawn of evolution. However, the state of aggregation hereassumed, from the known laws of matter and from analogy, callsfor explanation as probably the result of prior diffusion, when,of course, the difficulty is only put back, not set at rest. Nordo I think the primitive collision in harmony with the number ofrelatively stationary nebula visible in space.
The metaphysical objection is, I find, also urged by GeorgeSalmon, late Provost of Trinity College, in favour of thecreation of the universe.—(_Sermons on Agnosticism_.)
A. Winchell, in _World Life_, says: "We have not
301
the slightest scientific grounds for assuming that matter existedin a certain condition from all eternity. The essential activityof the powers ascribed to it forbids the thought; for all that weknow, and, indeed, as the _conclusion_ from all that we know,primal matter began its progressive changes on the morning of itsexistence."
Finally, in reference to the hypothesis of a unique determinationof matter after eternal duration in the past, it may not be outof place to remind the reader of the complexity which modernresearch ascribes to the structure of the atom.
302
INDEX
A.
Abney, Sir Wm., on sensitisers, 210.
Abundance of life, numerical, 98-100.
Adaptation and aggressiveness of the organism, 80.
Additive law, the, with reference to alpha rays, 220.
Age of Earth, comparison of denudative and radioactive methods offinding, 23-29.
Aletsch glacier, 286.
Allen, Grant, on colour of Alpine plants, 104.
Allen, H. Stanley, on photo-electricity, 203.
Alpha rays, nature of, 214; velocity of, 214; effects of, ongases, 214; range of, in air, 215; visualised, 218; ionisationcurve of, 216; number of, from one gram of radium, 237; number ofions made by, 237.
Alpine flowers, intensity of colour of, 102.
Alps, history of, 141; Tertiary denudation of, 148; depth ofsedimentary covering of, 148; evidence of high pressures andtemperatures in, 149; recent theories of formation of, 150 _etseq._; upheaval of, 147; age of, 147; volcanic phenomenaattending elevation of, 147.
Andes, trough parallel to, 123; not volcanic in origin, 118.
Angle of friction on ice, 261-265, 281-283; on glass, 261-265.
Animate systems, dynamic conditions of, 67; and transfer ofenergy, 71; and old age, 72; mechanical imitation of, 76, 77.
Animate and inanimate systems compared, 73-75.
Appalachian range, formation of, 120.
Arrhenius, on elevation of continents, 17.
Aryan Era of India, 136.
Asteroids, probable origin of, 175; discovery of, 175; dimensionsof, 176; orbits of, 176; Mars' moons derived from, 177.
B.
Babbage and Herschel, theory of mountain building, 123.
Babes (and Cornil), size of spores, 98.
Becker, G. F., age of Earth by sodium collection, 14; age ofminerals by lead ratio, 20.
Berthelot, law of maximum work, 62.
Bertrand, Marcel, section of Mont Blanc Massif, 154.
Beta rays, nature of, 246; accompanied by gamma rays, 247;production of, by gamma rays, 247; as ionising agents, 249.
Biotite, containing haloes, 223; pleochroism of, 235; intensifiedpleochroism in halo, 235.
Body and mind, as manifestations of progressiveness of theorganism, 86.
Boltwood, age of minerals by lead ratio, 20.
Bose, theory of latent image, 203.
Bragg and Kleeman, on path of the alpha ray, 215; stopping power,219; laws affecting ionisation by alpha rays, 220; curve ofionisation and structure of the halo, 232.
Brecciendecke, sheet of the, 154.
Brdche, sheet of the, 154.
Burrard and Hayden on the Himalaya, 138; sections of theHimalaya, 139.
C.
Canals and "canali," 166; curvature of, and path of a satellite,188 _et seq._; double and triple accounted for, 186, 187;doubling of, 195; disappearance and reappearance of, 196-198;photography of, 198; not due to cracks, 167; not due to rivers,167; of Mars, double nature of, 166, 170; crossing dark regionsof planet's surface, 168; of Mars, Lowell's views on, 168 _etseq._; shown on Lowell's map, investigation of, 192 _et seq._;radiating, explanation of, 193, 194; number of, 194; developed bysecondary disturbances, 194; nodal development of, due to raisedsurface features, 195.
Chamberlin and Salisbury, the Laramide range, 121.
Clarke, F. W., estimate of mass of sediments, 9; age of Earth bysodium collection, 14; average composition of sedimentary andigneous rocks, 42; on average composition of the crust, 126;solvent denudation of the continents, 17, 40.
Claus, protoplasm the test of the cell, 67; abortion of uselessorgans, 69.
Coefficient of friction, definition of, 262; deduction of, fromangle of friction, 263; abnormal values on ice, 261-265, 282; forvarious substances, 265.
Continental areas, movements of, 144.
Cornil and Babes, size of spores, 98.
Croll, James, dawn of evolution, 301.
Crust of the Earth, average composition of, 126; depth ofsoftening in, 128.
Curie, definition of the, 256.
D.
Dana, on mountain building, 120.
Dawson, reduction of surface represented by Laramide range, 123.
Deccan traps, 137
_déferlement_, theory of, 155; explanation of, 155 _et seq._;temperature involved in, 156.
Deimos, dimensions of, 177; orbit of, 577.
De Lapparent, exotic nature of the Préalpes, 150.
De Montessus and the association of earthquakes withgeosynclines, 142.
Denudation as affected by continental elevation, 17; factorspromoting, 30 _et seg._; relative activity in mountains and onplains, 35-40; solvent, by the sea, 40; the sodium index of,46-50; thickness of rock-layer removed from the land, 51.
De Quincy, System of the Heavens, 200.
Dewar, Sir James, latent image formed at low temperatures, 202.
Dixon, H. H., and AGnadance of Life, 60.
Double canals, formation by attraction of a satellite, 585-187.
Douglass, A. E., observations on Mars, 167.
Dravidian Era of India, 135.
E.
Earth, early history of, 3, 4; dimensions of, relative to surfacefeatures, 117.
Earth's age determined by thickness of sediments, 5; determinedby mass of the sediments, 7; determined by sodium in the ocean,12; determined by radioactive transformations, 19; significanceof, 2.
Earthquakes associated with geosynclincs, 142.
Efficiency, tendency to maximum, in organisms, 113, 114.
Elements, probable wide diffusion of rare, 230; rarity ofradioactive, 241.
Elster and Geitel, photo-electric activity and absorption, 207;photo-electric properties of gelatin, 212; Emanation of radium,therapeutic use of, 256-259; advantages of, in medicine, 256;volume of, 257; how obtained, 257; use of, in needles, 258.
Equilibrium amount, meaning of, 254, 255.
Evolution and acceleration of activity, 79; of the universe noteternal a pane ante, 298.
F.
Faraday and ionisation, 57.
Finality of progress a part, post, 289.
Flahault, experiments on colour of flowers, 108.
Fletcher, A. L., proportionality of thorium and uranium, 26,
G.
Galileo, discovery of Jupiter's moons, 162.
Gamma rays, nature of, 247: production of, by beta rays, 247; asionising agents, 249.
Geddes and Thomson, hunger and living matter, 71.
Geiger, range of alpha rays in air, 215; ionisation affected byalpha rays in air, 216; on "scattering," 217; scattering and thestructure of the halo, 232.
Geikie, Sir A., uniformity in geological history, 15.
Geosynclines, 119; association with earthquakes and volcanoes,142; of the tethys, 142; radioactive heat in, due to sediments,130; temperature effects due to lateral compression of, 131.
Glacial epoch, phenomena of, 287.
Glacier motion, cause of. 285.
Glossopteris and Gangamopteris flora, 136.
Gondwanaland, 136.
Gradient of temperature in Earth's surface crust, 126.
H.
Haimanta period of India, 135.
Halley, Edmund, finding age by saltness of ocean, 13.
Hallwachs, photo-electric activity and absorption, 207.
Haloes, pleochroic, finding age of rocks by, 21; due to uraniumand thorium families, 227; radii of, 227; over-exposed andunderexposed, 228; intimate structure of, 229 _et seq._;artificial, 229; tubular, in mica, 230; extreme age of, 231;effect of nucleus on structure of, 232; inference from sphericalform of, in crystals, 233; structure of, unaffected by cleavage,235; origin of the name "pleochroic,"235; colouration due toiron, 235; colouration not due to helium, 236; age Of, 236; slowformation of, 237, 238; number of rays required to build, 237;and age of the Earth, 238-241.
Hayden, H.H., geology of the Himalaya, 134, 138, 139.
Heat-tendency of the universe, 62.
Heat emission from the Earth's surface, 126; from average igneousrock due to radioactivity, 126.
Helium and the alpha ray, 214, 222; colouration of halo not dueto, 236.
Hering, E., and physiological or unconscious memory, 111.
Herschel and Babbage theory of mountain building, 123.
Herschel, Sir W., on galaxy of milky way, 293.
Hertz, negative electrification discharged by light, 204.
Himalaya, geological history of, 134-139.
Hobbs, on association of earthquakes and geosynclines, 143.
Holmes, A., original lead in minerals, 20; age of Devonian, 21.
Horst concerned in Alpine _déferlement_, objections to, 156.
Hyperion, dimensions of, 177.
I.
Ice, melting of, by pressure, 267 _et seq._; expansion of waterin becoming, 267; lowering of melting-point by pressure, 267;fall of temperature under pressure, 268 _et seq._; viscosity of,284.
Igneous rocks, average composition of, 43.
Inanimate actions, dynamic conditions of, 61.
Inanimate systems, secondary effects in, 63-65; transfer ofenergy into, 66.
Indian geology, equivalent nomenclature of, 139.
Initial recombination of ions due to alpha rays, 221, 222, 231;and structure of the halo, 231.
Insect life in the higher Alps, 104, 105; destruction of, on theAlpine snows, 106.
Ionisation by alpha ray, density of, 221; importance in chemicalactions, 250; in living cell, 250.
Ions, number of, produced by an alpha ray, 237.
Isostasy, 53; and preservation of continents, 53.
Ivy, inconspicuous blossoms of, 107; delay in ripening seed,107.
K.
Kant and Laplace, material hypothesis of, does not account forthe past, 290.
Kelvin, Lord, experiment on effects of pressure on ice, 268-270.
Kleeman and Bragg. See Bragg.
Klopstock introduces skating into Germany, 273.
L.
Lakes, cause of blue colour of, 55.
Land, movements of the, 53, 54.
Laukester, Ray, the soma and reproductive cells, 85.
Lapworth, structure of the Scottish Highlauds, 153.
Latent heat of water, 266.
Latent image, formed at low temperatures, 202; Bose's theory of,203; photo-electric theory of, 204, 209 _et seq._
Least action, law of, 66.
Lembert and Richards, atomic weight of lead, 27.
Length of life dependent on conditions of structural development,93; dependent on rate of reproduction, 94.
Life-curves of organisms having different activities, 92.
Life, length of, 91.
Life waves of a cerial, 95; of Ausaeba, 87; of a species, 90.
Light, effects of, in discharging negative electrification, 204;chemical effects of, 205; experiment showing effect of, indischarging electrified body, 205.
Lindemann, Dr., duration of solar heat, 29.
Lowell, Percival, observations on Mars, 167 _et seq._; map ofMars, reliability of, 198.
Lucretius, birth-time of the world, 1.
Lugeon, formation of the Préalpes, 171; sections in the Alps,154.
Lyell, uniformity in geological history, 15.
M.
Magee, relative areas of deposition and denudation, 16.
Mars, climate of, 170; position in solar system, 174, 175;dimensions of satellites of, 177; snow on, 169; water on, 169;clouds on, 169; atmosphere of, 170; melting of snow on, 170;dimensions of canals, 171; signal on, 172; times of opposition,164; orbit of, 165; distance from the Earth, 165; eccentricity ofhis orbit, 165; observations of, by Schiaparelli, 165, 166;Lowell's observations on, 167 _et seq._
Maxwell, Clerk, changes made under constraints, 65; onconservation of energy, 61.
M'Connel, J. C., viscosity and rigidity of ice, 284.
Memory, physiological, 111, 112.
Metamorphism, thermal, in Alpine rocks, 132, 149
Millicurie, definition of, 256.
Molasse, accumulations of, 148.
Morin, coefficients of friction, 265.
Morphy, H., experiments on coefficient of friction of ice, 281.
Mountain-building and the geosynclines, 119-121; conditioned byradioactive energy, 125; energy for, due to gravitation, 122;reduction of surface attending, 123; depression attending, 123;instability due to thermal effects of compression, 132; igneousphenomena attending, 132; rhythmic character of, accounted for,133; movements confined to upper crust, 122; movements due tocompressive stresses in crust, 122; movements, rhythmic characterof, 121.
Mountain ranges built of sedimentary materials, 118.
Müller, J., coefficient of friction of skate on ice, 265, 274.
Muth deposits of India, 135.
N.
Newton, Professor, of Yale, on origin of Mars' satellites, 177.
Nucleus, dimensions of, 237; amount of radium in, 238.
Nummulitic beds of Himalaya, 138.
O.
Ocean, amount of rock salt in, 50; cause of black colour of, 55;estimated mass of sediments in, 48; increase of bulk due tosolvent denudation, 52; its saltness due to denudation, 41.
Old age and death, 82-85; not at variance with progressiveactivity, 83.
Organic systems, origin of, 78.
Organic vibrations, 86 _et seq._
Organism and accelerative absorption of energy, 79; and economy,109-111; and periodic rigour of the environment, 94,95.
Organism and sleep, 95; ultimate explanation of rythmic eventsin, 96, 97; law of action of, 68 _et seq._; periodicity of; andlaw of progressive activity, 82 _et seq._
P.
Penjal traps, 135.
Pepys and skating, 273.
Perry, coefficient of friction of greased surfaces, 265.
Phobos, dimensions of, 177; orbit of, 177.
Photoelectric activity and absorption, 207; persists at lowtemperatures, 208, 209; not affected by solution, 213.
Photo-electric experiment, 205; sensitiveness of the hands, 207;theory of latent image, 204, 209 _et seq._
Photographic reversal, experiments on, by Wood, 211; theory of,210.
Piazzi, discovery of first Asteroid, 175.
Pickering, W. H., observations on Mars, 167.
Planet, slowing of axial rotation of, 189.
Plant, expectant attitude of, 109.
Pleochroic haloes, measurements of, 224; theory of, 224 _etseq._; true form of, 226; radius of, and the additive law, 225;absence of actinium haloes, 225; see _also_ Haloes; mode ofoccurrence of, 223 _et seq._
Poole, J. H. J., proportionality of thorium and uranium, 26.
Poulton, uniformity of past climate, 17.
Pratt, Archdeacon, and isostasy, 53.
Préalpes, exotic nature of, 150, 151.
Prematerial universe, nature of a, 297, 300.
Prestwich and thickness of rigid crust, 128; history of thePyrenees, 140.
Primitive organisms, interference of, 89; life-curves of, 88.
Proctor and orbits of Asteroids, 176.
Protoplasm, encystment of, 68.
Purana Era of India, 134.
Pyrenees, history of, 140.
R.
Radioactive elements concerned in mountain building, 125.
Radioactive layer, failure to account for deep-seatedtemperatures, 127; assumed thickness of, 128; temperature at baseof, due to radioactivity, 129; in the upper crust of the Earth,125; thickness of, 126-128.
Radioactive treatment, physical basis of, 251.
Radioactivity and heat emission from average igneous rock, 126;rarity of, established by haloes, 241, 243.
Radium, chemical nature and transmutation of, 244-245; emanationof, 245; rays from, 253, 254; table of family of, 253; period of,253; small therapeutic value of, 254.
Radium C, therapeutic value of, 254; rays from. 254; generationof, 254.
Rationality, conditions for development of, 163.
Rays, similarity in nature of gamma, X, and light rays, 248;effects on living cell, 251; penetration of, 251.
Reade, T. Mellard, finding age of ocean by calcium sulphate, 13.
Recumbent folds, formation of, 155 _et seq._
Regelation, 284; affecting glacier motion, 285.
Reversal, photographic, explanation of, 211.
Richards and Lembert, atomic weight of lead, 27.
Richter, Jean Paul, Dream of the Universe, 200.
Rock salt in the ocean, amount of, 13.
Rocks, average composition of, 43; radioactive heat from, 126;rate of solution of, 36.
Russell, I. C., river supply of sediments, 10.
Rutherford, Sir E., determination of age of minerals, 19, 20; ageof rocks by haloes, 22; derivation of actinium, 226; artificialhalo, 229; number of alpha rays from one gram of radium, 237.
S.
Salt range deposits of India, 134. 135.
Saltness of the ocean due to denudation, 41-46.
Salisbury (and Chamberlin), the Larimide range, 121.
Salmon, Rev. George, on creation, 301.
Satellite, velocity of, in its orbit, 191; method of finding pathof, over a rotating primary, 189 _et seq._; direct andretrograde, 178; ultimate end of, 178; path of, when falling intoprimary, 179; effect of Mars' atmosphere on infalling satellite,179; stability of close to primary, 180; effects of, on crust ofprimary, 180 _et seq._
Schiaparelli, observations on Mars, 165 166.
Schmidt, C., original depth of Alpine layer, 131-148; structureof the Alps, 152.
Schmidt, G. C., on photo-electricity, 207, 208; effect ofsolution on photo-electric activity, 213.
Schuchert, C., average area of N. America during geological time,16.
Sedimentary rocks, average composition of, 43; mass of,determined by sodium index, 47.
Sedimentation a convection of energy, 133.
Sediments, average river supply of, 11; on ocean floor, mass of,48; average thickness of, 49; precipitation of, by dissolvedsalts, 56-58; radioactivity of 130; radioactive heat of,influential in mountain building, 130, 131; rate of collecting,7; determination of mass of, 8; river supply of, 10; totalthickness of, 6.
Semper, energy absorption of vegetable and animal systems, 78.
Sensitisers, effects of low temperature on, 210.
Simplon, radioactive temperature in rocks of, before denudation,132.
Skates, early forms of, 273; principles of construction of, 273_et seq._; action of, on ice, 276; bite of, 278-280.
Skating not dependent on smoothness of ice, 260; history of,273.
Skating only possible on very few substances, 279.
Soddy, F., on isotopes, 24.
Sodium, deficiency of, in sediments, 44; discharge of rivers,14.
Soils, formation of, 37-39; surface area exposed in, 39.
Sollas, W. J., age of Earth by sodium in ocean, 14; thickness ofsediments, 6.
Spencer, on division of protoplasm, 67.
Spores, number of molecules in, 97.
Stevenson, Dr. Walter C., and technique of radioactive treatment,259.
Stoletow, photo-electric activity anal absorption, 207.
Stopping power of substances with reference to alpha rays, 219.
Struggle for existence, dynamic basis of, 80.
Strutt, Prof. the Hon. R. J., age of geological periods, 20;radioactivity of zircon, 223.
Sub-Apennine series of Italy, 148.
Suess, nature of earthquakes. 143.
Survival of the fittest and the organic law, 80.
T.
Talchir boulder-bed, 136.
Temperature gradient in Earth's crust, 126.
Termier, section of the Pelvoux Massif, 254.
Tethys, early extent of, 135-137; geosynclines of, 142.
Thermal metamorphism in Alpine rocks, 132, 149.
Thomson, James, prediction of melting of ice by pressure, 267.
Thorium and uranium, proportionality of, in older rocks, 26.
Triple canals, formation of, by attraction of a satellite, 187.
Tyndall, colour of ocean water, 55.
U.
Uniformitarian view of geological history, 15-18.
Universe, simultaneity of the, 293-295.
Uranium-radium family of elements, table of, 253.
V.
Val d'Hérens, earth pillars of, 33.
Van Tillo, nature of continental rock covering, 9.
Vegetable and animal systems, relative absorption of energy of,78.
Vegetative organs, struggle between, 105, 106.
Volcanoes and mountain ranges, 118; associated with geosynclines,142; Oligocene and Miocene of Europe, 147.
W.
Weinschenk and thermal metamorphism, 132,
149.
Weismaun, encystment of protoplasm, 68; length of life andsomatic cells, 96; origin of death, 83; tendency to earlyreproductiveness, 98.
Wilson, C. T. R., visualised alpha rays, 218.
Winchell, progressive changes of matter not eternal, 302.
Wood, R. W., on photographic reversal, 211.
Z.
Zircon, radioactivity of, 223; as nucleus of halo, 223.