[ 262 ] 



XLI V. On the Specific Heat of the Gases. By W. T. Hay- 

 craft, Esq. 

 [Concluded from p. 207.] 

 Experiments on Hydrogen. 



HYDROGEN gas was procured from the decomposition of 

 water by means of sulphuric acid and zinc. The part B 

 Plate II., was filled with the same, and the following experi- 

 ments were made. No. 1. 



In this experiment the calorimeters were filled with water 

 of the same temperature, and the process was conducted on 

 rather a different principle than the former ; namely, it was 

 continued until the calorimeters ceased to rise in temperature, 

 or, rather, till the temperature began to fall. This latter cir- 

 cumstance would take place when the heat communicated by 

 the gas was exactly equal to that abstracted by the colder sur- 

 rounding medium. The number of degrees of temperature, 

 then, which each gas would sustain in its calorimeter, will be 

 the ratio of its power for giving out heat, and consequently of 

 its capacity for caloric. 



The temperature of calorimeter A, at the beginning of the 

 experiment, was about 50°, and after 1 05 minutes the tem- 

 perature of calorimeter A was 82°i|, and that of B, contain- 

 ing hydrogen gas, was 82°^§, and the surrounding medium 

 60°2%, indicating the comparative capacity of hydrogen to be 

 98-64, being a difference so trifling, that it may be regarded 

 as the same as that of atmospheric air; if we make allowance 

 for the evident greater ratio in its heating, and the smaller 

 ratio of its rate of cooling at the end of the experiment. This 

 will be seen by the following table. 



Temperature of A, Temperature of B, 



containing Hy- 

 drogen Gas. 



50° 



58-6 

 ™H 

 "A 



76 



77^ 



78£g 



81 



82j 9 T 

 82& 

 82£f 



82 16 - 



82£{j No. 2. 



