212 Dr. A. Naumann on the Specific Heat of Gases 



§ 3. Table of the numerical values of the specific heats of gases, 

 and connexion of the differences between the values found and 

 those calculated for the state of perfect gases with chemical 

 composition. 



In the annexed Table there are contained : — 



In column 1, the names of the gases. 



In column 2, their chemical composition. 



In column 3, in general, the theoretical specific gravities given 



by Regnault*. These numbers were recalculated (by the for- 



, molecular weiqht\ , ,. , . , . , 



mula s= f^ttti — - — 1 ' and the number obtained was mtro- 



28*94 / ' 



duced in place of the one given by Regnault whenever the dif- 

 ference between them was great enough to affect the third deci- 

 mal place of the values in column 5. In order to distinguish 

 the numbers thus substituted, they are given with only three 

 places of decimals. For the specific heat of nitrogen, referred 

 to volume, it is immaterial whether the specific gravity 0*9713 

 given by Regnault, or the theoretical specific gravity 0*968 be 

 adopted, inasmuch as Regnault calculated it directly from the 

 specific heats of oxygen and air, and then deduced from it the 

 specific heat of the unit of weight. 



In column 4, the value of the specific heats of equal weights 

 under constant pressure, as given by Regnault. 



In column 5, the specific heats of equal volumes under constant 

 pressure, deduced from the numbers in the last column by multi- 

 plying by the specific gravities. The evidently erroneousf 

 numbers 0*4106 J and 0*4160 § given by Eegnault for ethylene, 

 are replaced by the right ones. 



In column 6, the theoretical specific heats of equal volumes, cal- 

 culated for the condition of perfect gases according to the equa- 

 tion 



7 '=(rc + 5).0-034. 



In column 7, the difference between the values given in 

 columns 5 and 6. 



In column 8, the number of atoms contained in a molecule. 



In column 9, the theoretical ratio of the two specific heats of 

 equal volumes (that is, the specific heat under constant pressure 

 and that at constant volume), calculated for the condition of per- 

 fect gases according to the equation 



<y' _n-\-5 



7 n + 3 



* Op. cit. pp. 303, 311, 313, 318 (also Will, Jahresbericht fur Chemie, 

 1863, p. 83 et seq.). 

 t Regnault, op. cit. p. 142. % Ibid. § Op. cit. p. 318. 



