148 Intelligence and Miscellaneous Articles. 



heat that ought to have been emitted according to the law of Dulong 

 and Petit. It is found to be much more than 5-6 calories. — 

 Bibliotheque Universelle, Archives des Sciences Physiques et Naturelles, 

 Jan. 15, 1879, t. i. pp. 86-90. 



ON ELECTROCHEMICAL ACTIONS UNDER PRESSURE. 

 BY A. BOUVET. 



In a series of about fifty experiments, each lasting several hours, 

 and during which I have been able to produce with extreme facility- 

 pressures of 100, 200, 300 atmospheres, &c, I constantly recog- 

 nized the existence of the two following laws : — 



(1) The decomposition of water by a current is independent of 

 the pressure ; 



(2) The quantity of electricity necessary for decomposing one 

 and the same weight of water is sensibly the same, whatever may 

 be the pressure at which the decomposition is effected. 



I have ascertained by experiment that the mechanical theory of 

 heat perfectly accounts for these two laws. Thus, by taking ad- 

 vantage of the fact that gases produced in the midst of water are 

 obtained at a sensibly fixed temperature, I verified the formula 

 which represents the work expended for the compression of gases 

 without change of temperature : — ■ 



T=PV (— = PV log hypL. 



T, work =V 1 , final volume after the expansion ; 



Y, volume of the compressed gas ; 



P, pressure. 



The result of the experiment made with gases at 200 atmospheres 

 agreed perfectly with the result calculated after the above formula. 



For the sake of brevity, I will only add the following : — 



1st. The oxygen and hydrogen, at whatever pressure, are libe- 

 rated with equal facility. 



2nd. These two gases may be produced in a single test-tube or 

 in two ; in neither case are there any secondary phenomena deter- 

 mining even partial recombination, as has hitherto been believed. 

 The^m^'stf and constant indications of the manometer, the regular 

 increments of pressure, ascertained from minute to minute during 

 several consecutive hours, leave no doubt on this point. 



3rd. The oxygen and hydrogen, when they are collected in one 

 and the same test-tube, even under considerable pressure, and 

 although constituting the explosive mixture, are not at all dan- 

 gerous. 



The electrodes I employed were of platinum. I always took care 

 to let them be completely immersed. 



' In the course of my experiments, lasting several months, I never 

 ascertained any appreciable variation of temperature, although I 

 sometimes employed currents possessing very energetic tension. — 

 Comptes Rendus de VAcademie des Sciences, Dec. 30, 1878, tome 

 lxxxvii. p. 1068-69. 



