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TEE POPULAR SCIENCE MONTELY.— SUPPLEMENT. 



It may be remarked that the conditions above 

 arrived at, as a basis for recurring changes in the 

 universe, were not deduced solely with this object 

 in view ; but these very conditions follow inde- 

 pendently as necessary consequences of the ex- 

 planation of gravitation afforded by the kinetic 

 theory, so that it becomes a remarkable fact that 

 the very conditions that follow on the explanation 

 of gravitation are precisely of that character re- 

 quired to account for recurring changes in the 

 universe. The more the subject is reflected on, 

 the more apparent will it become that, in broad 

 principle, other conditions for producing recur- 

 ring changes are not conceivable — keeping in view 

 the necessity (in order to effect recurrence) that 

 the cooled-down material of the universe should 

 be that material which is utilized for the develop- 

 ment of fresh centres of heat ; and there would 

 appear to be a simple grandeur (not out of har- 

 mony with the recognized characteristics of Na- 

 ture) in this great result being brought about by 

 the mere movement of the stars according to the 

 kinetic theory. Also, there would be a sort of 

 harmony or analogy in the stellar masses and the 

 media in which they are immersed moving under 

 the same dynamical principles. Moreover, the 

 kinetic theory has been mathematically proved 

 (when a large number of masses are concerned) 

 to produce a system of order and symmetry (or 

 mean similarity of the conditions in all parts of 



mersed in another gas) break up from any cause into 

 their components, each of these smaller components 

 tends to acquire from the rest of the gas the same ab- 

 solute kinetic energy of translatory motion as the 

 entire compound molecule possessed (before it was 

 broken up); so thst, therefore, the total energy of a 

 given portion of gas may be suddenly greatly aug- 

 mented hy the mere breaking up of its (compound) 

 molecules into parts. If we imagine any limited por- 

 tion of a gas to be immersed in another gas of unlim- 

 ited extent (or if the portion of gas be supposed in- 

 closed in some way so as to permit expansion, and at 

 the same time to allow a free exchange of energy be- 

 tween it and the other gas), then a change in the state 

 of aggregation — by the breaking up into parts of the 

 compound molecules of the inclosed gas — will be fol- 

 lowed by a considerable transference of energy from 

 the outer gas to the inclosed gas ; for when equilibri- 

 um is again attained, each of the small parts into which 

 the compound molecules of the inclosed gas are split 

 up will have acquired from the outer gas the same ab- 

 solute kinetic energy of translatory motion as the 

 entire molecule possessed before it was broken up. 

 Thus, the mere act of breaking up (disintegration) of 

 matter, immersed iu a medium inclosing a store of mo- 

 tion, may cause considerable transference of energy 

 from this medium to the immersed matter, tending to 

 produce expansion and rebound. Possibly, this prin- 

 ciple might also have some bearing on the disintegrat- 

 ing changes continually taking place in the universe. 



the system) which is rigidly and automatically 

 maintained by a process of self-correction under 

 dynamical principles — a self-acting adjustment 

 of the motions continually taking place, whereby 

 a system of harmony and order is maintained 

 everywhere, a perfect state of mobile equilibrium 

 existing in all parts. 



Those who regard the physical causation of 

 the past in the light of the physical causation of 

 the present, or who look upon the principle of the 

 conservation of energy as a truth as necessary 

 in the past as in the present (or who look upon 

 physical truths as independent of time), are 

 bound to believe that some process of recurrence 

 must exist, whereby useful change and activity 

 are continued in the universe, and the purposeless 

 end of a changeless chaos prevented ; and that 

 we should seek for the explanation of this, not 

 so much with the view to prove the fact thereby, 

 but rather as a satisfaction or confirmation of a 

 fact we already had logical grounds for believing 

 to exist. As we happen to have given consider- 

 able time and thought to the problem of gravita- 

 tion on the basis of Le Sage's fundamental idea, 

 we have considered ourselves justified in calling 

 attention to the important consequences and 

 modified views regarding natural phenomena that 

 the acceptance of the physical theory of gravita- 

 tion entails. 



The phenomena of Nature would thus consist 

 in cyclical processes involving transferences of 

 motion from physical media in space to matter, 

 and back again to these media (in a circle), the 

 collective sum total of energy in matter and in 

 these media remaining at every instant constant, 

 in accordance with the principle of the conserva- 

 tion of energy. The cyclical processes thus tak- 

 ing place on a great scale in the universe are im- 

 itated on a smaller scale in the ordinary inter- 

 changes of energy on the earth's surface, or all 

 the ordinary processes of " work," or the deri- 

 vation of power, show themselves to be cyclical 

 processes on the recognition of the stores of 

 motion in space rendered necessary by the phys- 

 ical theory of gravitation. For suppose, for. ex- 

 ample, we derive power from the fall of water, 

 and use it through machinery for lifting weights 

 or elevating materials — then the motion derived 

 at the descent of the water comes from the store 

 of motion in the gravific medium, and passes to 

 the gravific medium again in a cyclical process, in 

 the operation of elevating the materials in oppo- 

 sition to the dynamic action of the gravific me- 

 dium which tends to urge them toward the earth. 

 If, instead of elevating materials, the work be 



