346 SOCIETY OF PHYSICS AND NATURAL HISTORY, OF GENEVA. 



Marius. The paper of M. Gautier bas been inserted in the Archives 

 of Science 1871, vohiine XLI, page 27. He has continued to keep us 

 informed in regard to iiui)ortaut discoveries made in the domain of gen- 

 eral astronomy. 



Professor Cellerier presented a paper upon the molecular coustitutiou 

 of gas. According to modern hypothesis, gases are composed of mole- 

 cules, endowed with a movement of translation in every direction, and 

 freed during the major part of the duration of this movement, from all 

 mutual action, this action only rev^ealing itself by shocks. Whatever 

 be the nature of the latter, their consequences, according to the general 

 laws of mechanics, can only be similar to those which are produced by 

 the shock of two perfectly elastic bodies. The movement after the 

 shock depends either upon the direction of the movement before the 

 shock, or, upon fortuitous circumstances, such as the direction of the 

 plane of the shock. If we admit tliat, during a certain time, the di- 

 rection of this plane is always parallel to one or the other of the 

 three rectangular planes, the result must be that the diffusion of the densi- 

 ties, in all the masses would occur immediately, contrary to all experience. 

 It would be the same for an infinity of other directions of the plane of the 

 shock. M. Cellerier has therefore concluded that the theory of gases 

 which Chiusius and other physicists have proposed is not absolutely 

 admissible, at least under this simple form. This communication has 

 given rise to some observations by A. de la Rive, upon the impossi- 

 bility of doing without the intervention of ether, in explaining 

 the phenomena which the gases present. 



Our compatriot, M. Duperrey, for a number of years professor at 

 Paris, has taken advantage of a sojourn at Geneva, to lay before the so- 

 ciety some researches which he has undertaken, to find a simple and 

 practical relation between the temperature and the maximum tension 

 of steam. He has obtained the following result, remarkable for its sim- 

 13licij;y, that this tension represented in kilogrammes by square, centi- 

 meters, is nearly exactly equal to the fourth power of the temi)erature. 



M. Serra Carpi, a Roman engineer, in i^assing through Geneva, has 

 given some details relative to the variation of the mean temperature at dif- 

 ferent heights, a subject treated in a i)amphlet, of which he has given 

 to the society a copy. Professor Marcet, in a letter addressed from 

 London to M. de la Rive, has given an account of the last observations 

 of Dr. Carpenter upon the waters of the jNfediterranean. These observa- 

 tions were extended to a depth of 3,000 meters. At this depth the 

 water is turbulent, and contains a great quantity of dissolved gas. The den- 

 sity changes from 10O.27 at the surface, to 10O.20 at 2,000 meters, and to 

 10^.28 at 3,000 meters of depth. The denser water rests therefore upon 

 water less dense ; this singular fact can be explained by currents, of 

 which Dr. Carpenter has without doubt confirmed the existence. 



In the domain of physics, Professor Regnault has presented to the 

 society an important comnumication, which occupied an entire meeting. 



