166 MR W. J. M. RANKINE ON THE 
Hence the following are the values of the apparent specific heats of unity of 
weight of a theoretically perfect gas under different circumstances :— 
General value of the total apparent specific heat :—_ 
ah iy Seka PKs a. 
K=oou (yt C-#) (5 +7q5) } 
ie eee © a! a 
Sonmn a (= +5-pas) 
Apparent specific heat at constant volume :— 
. 1 ye Ke 
Kau ints a} 

(18.) 
Apparent specific heat under constant pressure :— 
iret t 1 1 Ke 
oan (wt —=) 
kK? 
=%{1+N (1-5) | 
The ratio of the apparent specific heat under constant pressure to the appa- 
rent specific heat at constant volume is the following :— 
K 

14N 1-+) fen 
= ( T{=14+N-——_7_, . . . (9) 
4 1+N (7-5) 1+N(E- :) 
The value of « is unknown; and, as yet, no experimental data exist from 
which it can be determined. I have found, however, that practically, results of 
sufficient accuracy are obtained by regarding x as so small in comparison with r, 
on ae ee 
2 
that “, and a@ fortiori > may be neglected in calculation. 4 
Thus are obtained the following approximate results, for perfect gases, and 7 
gases which may without material error be treated as perfect. 
General value of the total apparent specific heat :— 
itt 1 7 dV 
K=GaM\nty¥ Ts) She po 
rf (5 1 7TadP 
Nie. ae ) 
~CnM Pdr 
Apparent specific heat at constant volume :— (20) 
4 ite 
&=camn —* 
being equal to the real specific heat. 
Apparent specific heat under constant pressure :— 
K 1) = (14+N) 
me 8 
oan (3 
