342 Prof. Apjohn on the Specific Heats of the Gases, 



experiment that the fluid stood at the same level in the two 

 arms of the manometer, and that, therefore, the value of p 

 was given by the height of the barometer. 



The following are, in a tabular form, some of his observa- 

 tions, the pressure being converted from centimetres into 

 inches, and the temperatures reduced from the centigrade 

 scale to that of Fahrenheit. The number of his experiments 

 with air was 12, with oxygen 9, with hydrogen 9, with car- 

 bonic oxide 6, with nitrous oxide 6, and carbonic acid 8. 

 But two for each gas are given here, namely, that in which t 

 was a maximum, and that in which it was a minimum, for the 

 several results in each series are so consistent that it would 

 answer no useful purpose to quote them all. 



The numbers in the last column of preceding table, are 



f^e 30 



those which result from the formula a = 



X — , which 



4'8 ds p 



I have applied in my own researches, and they are all, it will 

 be seen, less than the corresponding numbers in the preceding 

 column, or those deduced by Suerman himself. 



The following table exhibits in adjacent columns the spe- 

 cific heats of the respective gases under equal weights and 

 equal volumes as given by Suerman, and as deduced from his 

 experiments by my formula, the specific heat of air being in 

 both cases represented by unity. 



