the Specific Heats of Air. 287 



deduce the second equation therefrom. If we take -3 as small 

 compared with p, and b and -^ as both small compared with 



Q 11 



v, we must also take JK ^ as small compared with v, since 



6 v 6 



JK P = is of the same order as R „■ Neglecting all such 



small quantities, we obtain 

 (dXJ\ 



\ dv /T V ^ ' 



and this is true of a perfect gas. If we wish to keep small 

 quantities but reject their squares, we shall have 



(SH-W 



a 2a 



P 



v-b-~U 



v JJu 



= { 1+ m.( JK " +R ) + ?-Kk}^ 

 =Hffi (JK ' +E)+ t-re}- 



Mr. Love appears to have kept the first of the quantities 

 in curly brackets but to have rejected the rest ; and he has 

 given no good grounds for doing this. The terms which do 

 not appear in his equation are of equal importance with the 

 term which remains. 



I am, Gentlemen, 



Yours respectfully, 

 July 19 1899 JOHN RoSE-lNNES. 



