Chapter IX: Part 9

last for ever, and its past duration cannot be infinite." We do not know, indeed, the rate of progress of the chronometer, but if the dial be one divided into eternal durations the consummation of any finite physical change represents such a movement of the hand as is accomplished in a single vibration of the balance wheel.

Hence we must regard the hosts of glittering stars as a conflagration that has been simultaneously lighted up in the heavens. The enormous (to our ideas) thermal energy of the stars resembles the scintillation of iron dust in a jar of oxygen when a pinch of the dust is thrown in. Although some particles be burnt up before others become alight, and some linger yet a little longer than the others, in our day's work the scintillation of the iron dust is the work of a single instant, and so in the long night of eternity the scintillation of the mightiest suns of space is over in a moment. A little longer, indeed, in duration than the life which stirs a moment in response to the diffusion of the energy, but only very little. So must an Eternal Being regard the scintillation of the stars and the periodic vibration of life in our geological time and the most enduring efforts of thought. The latter indeed are no more lasting than

"... the labour of ants In the light of a million million of suns."

But the myriad suns themselves, with their generations, are the momentary gleam of lights for ever after extinguished.

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Again, science suggests that the present process of material aggregation is not finished, and possibly will only be when it prevails universally. Hence the very distribution of the stars, as we observe them, as isolated aggregations, indicates a development which in the infinite duration must be regarded as equally advanced in all parts of stellar space and essentially a simultaneous phenomenon. For were we spectators of a system in which any very great difference of age prevailed, this very great difference would be attended by some such appearance as the following:--

The aupearance of but one star, other generations being long extinct or no others yet come into being; or, perhaps, a faint nebulous wreath of aggregating matter somewhere solitary in the heavens; or no sign of matter beyond our system, either because ungathered or long passed away into darkness.[1]

Some such appearances were to be expected had the aggregation of matter depended solely on chance encounters of particles scattered through infinite space.

For as, by hypothesis, the aggregation occupies an infinite time in consummation it is nearly a certainty that each particle encountered after immeasurable time, and then for the first time endowed with actual gravitational potential energy, would have long expended this energy

[1] It is interesting to reflect upon the effect which an entire absence of luminaries outside our solar system would have had upon the views of our philosophers and upon our outlook on life.

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before another particle was gathered. But the fact that so many fires which we know to be of brief duration are scattered through a region of space, and the fact of a configuration which we believe to be a transitory ore, suggest their simultaneous aggregation here and there. And in the nebulous wreaths situated amidst the stars there is evidence that these actually originated where they now are, for in such no relative motion, I believe, has as yet been detected by the spectroscope. All this, too, is in keeping with the nebular hypothesis of Kant and Laplace so long as this does not assume a primitive infinite dispersion of matter, but the gathering of matter from finite distances first into nebulous patches which aggregating with each other have given rise to our system of stars. But if we extend this hypothesis throughout an infinite past by the supposition of aggregation of infinitely remote particles we replace the simultaneous approach required in order to accotnt for the simultaneous phenomena visible in the heavens, by a succession of aggregative events, by hypothesis at intervals of nearly infinite duration, when the events of the universe had consisted of fitful gleams lighted after eternities of time and extinguished for yet other eternities.

Finally, if we seek to replace the eternal instability involved in Kant's hypothesis when extended over an infinite past, by any hypothesis of material stability, we at once find ourselves in the difficulty that from the known properties of matter such stability must have been

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permanent if ever existent, which is contrary to fact. Thus the kinetic inertia expressed in Newton's first law of motion might well be supposed to secure equilibrium with material attraction, but if primevally diffused matter had ever thus been held in equilibrium it must have remained so, or it was maintained so imperfectly, which brings us back to endless evolution.

On these grounds I contend that the present gravitational properties of matter cannot be supposed to have acted for all past duration. Universal equilibrium of gravitating particles would have been indestructible by internal causes. Perpetual instability or evolution is alike unthinkable and contrary to the phenomena of the universe of which we are cognisant. We therefore turn from gravitating matter as affording no rational account of the past. We do so of necessity, however much we feel our ignorance of the nature of the unknown actions to which we have recourse.

A prematerial condition of the universe was, we assume, a condition in which uniformity as regards the average distribution of energy in space prevailed, but neterogeneity and instability were possible. The realization of that possibility was the beginning we seek, and we today are witnesses of the train of events involved in the breakdown of an eternal past equilibrium. We are witnesses on this hypothesis, of a catastrophe possibly confined to certain regions of space, but which is, to the motions and configurations concerned, absolutely unique, reversible to

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its former condition of potential by no process of which we can have any conception.

Our speculation is that we, as spectators of evolution, are witnessing the interaction of forces which have not always been acting. A prematerial state of the universe was one of unfruitful motions, that is, motions unattended by progressing changes, in our region of the ether. How extended we cannot say; the nature of the motions we know not; but the kinetic entities differed from matter in the one important particular of not possessing gravitational attraction. Such kinetic configurations we cannot consider to be matter. It was _possible_ to construct matter by their summation or linkage as the configuration of the crystal is possible in the clear supersaturated liquid.

Duration in an ether filled with such motions would pass in a succession of mere unfruitful events; as duration, we may imagine, even now passes in parts of the ether similar to our own. An endless (it may be) succession of unprogressive, fruitless events. But at one moment in the infinite duration the requisite configuration of the elementary motions is attained; solely by the one chance disposition the stability of all must go, spreading from the fateful point.

Possibly the material segregation was confined to one part of space, the elementary motions condensing upon transformation, and so impoverishing the ether around till the action ceased. Again in the same sense as the

298

stars are simultaneous, so also they may be regarded as uniform in size, for the difference in magnitude might have been anything we please to imagine, if at the same time we ascribe sufficient distance sundering great and small. So, too;, will a dilute solution of acetate of soda build a crystal at one point, and the impoverishment of the medium checking the growth in this region, another centre will begin at the furthest extremities of the first crystal till the liquid is filled with loose feathery aggregations comparable in size with one another. In a similar way the crystallizing out of matter may have given rise, not to a uniform nebula in space, but to detached nebula, approximately of equal mass, from which ultimately were formed the stars.

That an all-knowing Being might have foretold the ultimate event at any preceding period by observing the motions of the parts then occurring, and reasoning as to the train of consequences arising from these nations, is supposable. But considerations arising from this involve no difficulty in ascribing to this prematerial train of events infinite duration. For progress there is none, and we can quite as easily conceive of some part of space where the same Infinite Intelligence, contemplating a similar train of unfruitful motions, finds that at no time in the future will the equilibrium be disturbed. But where evolution is progressing this is no longer conceivable, as being contradictory to the very idea of progressive development. In this case Infinite Intelligence

299

_necessarily_ finds, as the result of his contemplation, the aggregation of matter, and the consequences arising therefrom.

The negation of so primary a material property as gravitation to these primitive motions of (or in) the ether, probably involves the negation of many properties we find associated with matter. Possibly the quality of inertia, equally primary, is involved with that of gravitation, and we may suppose that these two properties so intimately associated in determining the motions of bodies in space were conferred upon the primitive motions as crystallographic attraction and rigidity are first conferred upon the solid growing from the supersaturated liquid. But in some degree less speculative is the supposition that the new order of motions involved the transformation of much energy into the form of heat vibrations; so that the newly generated matter, like the newly formed crystal, began its existence in a medium richly fed with thermal radiant energy. We may consider that the thermal conditions were such as would account for a primitive dissociation of the elements. And, again, we recall how the physicist finds his estimate of the energy involved in mere gravitational aggregation inadequate to afford explanation of past solar heat. It is supposable, on such a hypothesis as we have been dwelling on, that the entire subsequent gravitational condensation and conversion of material potential energy, dating from the first formation of matter to the stage of star formation

300

may be insignificant in amount compared with the conversion of etherial energy attending the crystallizing out of matter from the primitive motions. And thus possibly the conditions then obtaining involved a progressively increasing complexity of material structure the genesis of the elements, from an infra-hydrogen possessing the simplest material configuration, resulting ultimately in such self-luminous nebula as we yet see in the heavens.

The late James Croll, in his _Stellar Evolution_, finds objections to an eternal evolution, one of which is similar to the "metaphysical" objection urged in this paper. His way out of the difficulty is in the speculation that our stellar system originated by the collision of two masses endowed with relative motion, eternal in past duration, their meeting ushering in the dawn of evolution. However, the state of aggregation here assumed, from the known laws of matter and from analogy, calls for explanation as probably the result of prior diffusion, when, of course, the difficulty is only put back, not set at rest. Nor do I think the primitive collision in harmony with the number of relatively stationary nebula visible in space.

The metaphysical objection is, I find, also urged by George Salmon, late Provost of Trinity College, in favour of the creation of the universe.--(_Sermons on Agnosticism_.)

A. Winchell, in _World Life_, says: "We have not

301

the slightest scientific grounds for assuming that matter existed in a certain condition from all eternity. The essential activity of the powers ascribed to it forbids the thought; for all that we know, and, indeed, as the _conclusion_ from all that we know, primal matter began its progressive changes on the morning of its existence."

Finally, in reference to the hypothesis of a unique determination of matter after eternal duration in the past, it may not be out of place to remind the reader of the complexity which modern research ascribes to the structure of the atom.

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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 of finding, 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, on gases, 214; range of, in air, 215; visualised, 218; ionisation curve of, 216; number of, from one gram of radium, 237; number of ions made by, 237.

Alpine flowers, intensity of colour of, 102.

Alps, history of, 141; Tertiary denudation of, 148; depth of sedimentary covering of, 148; evidence of high pressures and temperatures in, 149; recent theories of formation of, 150 _et seq._; upheaval of, 147; age of, 147; volcanic phenomena attending 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 of energy, 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; dimensions of, 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 of minerals 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; intensified pleochroism in halo, 235.

Body and mind, as manifestations of progressiveness of the organism, 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 of ionisation 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 the Himalaya, 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 regions of planet's surface, 168; of Mars, Lowell's views on, 168 _et seq._; shown on Lowell's map, investigation of, 192 _et seq._; radiating, explanation of, 193, 194; number of, 194; developed by secondary disturbances, 194; nodal development of, due to raised surface features, 195.

Chamberlin and Salisbury, the Laramide range, 121.

Clarke, F. W., estimate of mass of sediments, 9; age of Earth by sodium collection, 14; average composition of sedimentary and igneous 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 useless organs, 69.

Coefficient of friction, definition of, 262; deduction of, from angle of friction, 263; abnormal values on ice, 261-265, 282; for various 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 of softening 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 with geosynclines, 142.

Denudation as affected by continental elevation, 17; factors promoting, 30 _et seg._; relative activity in mountains and on plains, 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 surface features, 117.

Earth's age determined by thickness of sediments, 5; determined by mass of the sediments, 7; determined by sodium in the ocean, 12; determined by radioactive transformations, 19; significance of, 2.

Earthquakes associated with geosynclincs, 142.

Efficiency, tendency to maximum, in organisms, 113, 114.

Elements, probable wide diffusion of rare, 230; rarity of radioactive, 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 not eternal 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; as ionising agents, 249.

Geddes and Thomson, hunger and living matter, 71.

Geiger, range of alpha rays in air, 215; ionisation affected by alpha rays in air, 216; on "scattering," 217; scattering and the structure 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 uranium and thorium families, 227; radii of, 227; over-exposed and underexposed, 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 spherical form of, in crystals, 233; structure of, unaffected by cleavage, 235; origin of the name "pleochroic,"235; colouration due to iron, 235; colouration not due to helium, 236; age Of, 236; slow formation 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 igneous rock due to radioactivity, 126.

Helium and the alpha ray, 214, 222; colouration of halo not due to, 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 water in 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 of energy 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 the Alpine snows, 106.

Ionisation by alpha ray, density of, 221; importance in chemical actions, 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 for the 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, in discharging electrified body, 205.

Lindemann, Dr., duration of solar heat, 29.

Lowell, Percival, observations on Mars, 167 _et seq._; map of Mars, 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 of his orbit, 165; observations of, by Schiaparelli, 165, 166; Lowell's observations on, 167 _et seq._

Maxwell, Clerk, changes made under constraints, 65; on conservation 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 by radioactive energy, 125; energy for, due to gravitation, 122; reduction of surface attending, 123; depression attending, 123; instability due to thermal effects of compression, 132; igneous phenomena attending, 132; rhythmic character of, accounted for, 133; movements confined to upper crust, 122; movements due to compressive stresses in crust, 122; movements, rhythmic character of, 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 to solvent denudation, 52; its saltness due to denudation, 41.

Old age and death, 82-85; not at variance with progressive activity, 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 events in, 96, 97; law of action of, 68 _et seq._; periodicity of; and law 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 low temperatures, 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 _et seq._; true form of, 226; radius of, and the additive law, 225; absence of actinium haloes, 225; see _also_ Haloes; mode of occurrence 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 the Pyrenees, 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-seated temperatures, 127; assumed thickness of, 128; temperature at base of, 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; emanation of, 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; generation of, 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; age of rocks by haloes, 22; derivation of actinium, 226; artificial halo, 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 path of, over a rotating primary, 189 _et seq._; direct and retrograde, 178; ultimate end of, 178; path of, when falling into primary, 179; effect of Mars' atmosphere on infalling satellite, 179; stability of close to primary, 180; effects of, on crust of primary, 180 _et seq._

Schiaparelli, observations on Mars, 165 166.

Schmidt, C., original depth of Alpine layer, 131-148; structure of the Alps, 152.

Schmidt, G. C., on photo-electricity, 207, 208; effect of solution 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 dissolved salts, 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; total thickness 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 of sediments, 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 and somatic cells, 96; origin of death, 83; tendency to early reproductiveness, 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.