THE DYNAMICAL THEORY OF GASES. 5 



If the mass of gas is of the same temperature throughout there will be 

 no conduction of heat, and the equation (94) will become 



2- = 3/3-=3/3 ........................ (106), 





which gives the relation between the density and the temperature in a gas 

 expanding without exchange of heat with other bodies. We also find 



dp _ 8p 80 



P " P " e 



_2 + 3^9p 



~W~ 7' }> 



which gives the relation between the pressure and the density. 



Specific Heat of Unit of Mass at Constant Volume. 

 The total energy of agitation of unit of mass is /JF 3 = Z?, or 



*-* <>> 



If, now, additional energy in the form of heat be communicated to it without 

 changing its density, 



a*. ? &?* (no). 



2/3 2 p 6 



Hence the specific heat of unit of mass of constant volume is in dynamical 

 measure 



**.-*. (in) 



~a0 " 2 P 



VOL. II. 



