242 APPENDIX B. 



ties exist for gaseous substances, but such experi- 

 ments presented almost insurmountable difficul- 

 ties. 



The irregularities of specific heats of solid bodies 

 might have been attributed, it would seem, to the 

 latent heat employed to produce a beginning of 

 fusion a softening which occurs in most bodies 

 long before complete fusion. We might support 

 this opinion by the following statement: According 

 to the experiments of MM. Dulong and Petit, the 

 increase of specific heat with the temperature is 

 more rapid in solids than in liquids, although the 

 latter possess considerably more dilatability. The 

 cause of irregularity just referred to, if it is real, 

 would disappear entirely in gases. 



NOTE D. In order to determine the arbitrary 

 constants A, B, A', B' , in accordance with the 

 results in M. Dalton's table, we must begin by com- 

 puting the volume of the vapor as determined by 

 its pressure and temperature, a result which is 

 easily accomplished by reference to the laws of 

 Mariotte and Gay-Lussac, the weight of the vapor 

 being fixed. 



The volume will be given by the equation 



267 + tf 



v = c , 



P 

 in which v is this volume, t the temperature, p the 



