386 Intelligence and Miscellaneous Articles. 



12-2 



webers. The maximum of work is qn~m kilogrammetres per second ; 



lastly, the velocity which must be given to the machine to obtain 

 this maximum is given by the equation 



BT = 27rU= 0-653*. 

 — Comptes Rendus de VAcademie des Sciences, Sept 13, 1880, t. xci. 

 pp. 493-495. 



ON THE ABSOLUTE MEASURE OF PELTIER'S PHENOMENON AT THE 

 CONTACT OF A METAL AND ITS SOLUTION. BY E. BOUTYf . 

 Two coppered thermometers, as nearly equal as possible, and 

 sensitive to -gin* ' were lowered at the distance of 1 decim. from 

 each other, into a large vessel full of solution of sulphate or nitrate 

 of copper, which stood in a large cold-water bath. Thereupon the 

 temperature of the solution changed in 5 minutes y^ u° on h T ' Be- 

 tween the thermometers a current of the intensity i was conducted 

 through during two minutes ; the quantities of heat then observed 

 on the two thermometers were proportional to ~W=+ai+hi 2 , 

 where a and b are constants. That the indications of the thermo- 

 meters were in fact proportional to the quantities of heat produced 

 upon them follows from experiments, in which they were surrounded 

 in the fluid with German-silver spirals protected from the latter. 

 On the passage of currents i 1 through the spirals the heatings were 

 proportional to i*. In absolute measure (centim., gram, second) 

 the heat generated, simultaneously with Peltier's phenomenon, by 



T rfl? 



the current E in a second is 11= V -™, where A is the mechanical 



heat-equivalent, T the absolute temperature, and E the thermoelec- 



tromotive force. According to previous experiments by Bouty (Bei- 



cZE 

 blatter, iv. p. 680), for copper — =0-000696D =0-000696 . 1-12 . 10 8 



absolute units. Since J = 4-2 . 10 7 , it follows that 11 = 0-528. 



Further, the thermometer employed was heated in the liquid in 



2 minutes C, 471, for which 4*77 thermal units are requisite. From 



the formulae for W it resulted that during 2 minutes a= 6*018. 



4-77 1 

 According to this, 11 = 6-018 . k^hjt tqa =0*5078, which agrees 



very well with the above value. 



Similar results were given by salts of zinc and cadmium. Zinc 

 in a solution of zinc chloride shows a constant thermoelectromotive 

 force E in solutions the specific gravity of which is less than 1*6 ; 

 with higher degrees of concentration E rapidly diminishes. Peltier's 

 phenomenon II behaves in just the same way. Thus, 



Specific gravity .... 1-255 1*70 1-90 2-044 



Constant E 1 0-724 0-247 0-053 



Constant II 1 0-709 0-244 0-051 



* These experiments were made at the laboratory of the Soci^te* gen£- 

 rale d'Electricite. 



t Comptes Mendus, xc. pp. 987-990 (1880). 



