ON GASEOUS EXPLOSIONS. 195 
reckoned by merely multiplying the specific heat into the change of 
temperature corresponding to the change of state from A to B, the 
mass of the charge M being calculated from the general relation, 
PV 
M=7 ees a exe 48) 
corresponding values of P, V, and T being taken from any point 
on the path where they could be determined. It is known, however, 
that the specific heat is variable, and the Committee began their work 
by reviewing all the available experimental data in connexion with the 
subject. Several members of the Committee were themselves carry- 
ing out researches in relation to this problem at the same time. 
Data found to enable this Determination to be made. 
The aim of the Committee was to ascertain the true value of the 
specific heat at constant volume, Ky, or, to put it in another way, to 
ascertain the relation between the internal energy of the gas and its 
temperature. In dealing with gas-engine problems it is more 
convenient to combine equations (1) and (2) into a single expression in 
which the specific heat is given not in terms of the unit of mass, but 
in terms of the unit of volume at standard pressure and temperature. 
Substituting in equation (3) for the standard pressure, 1 atmosphere, 
for the standard temperature, 273° C. absolute, and for the gas con- 
stant, c=96, it will be found that the weight of a cubic foot of the 
working agent at standard temperature and pressure is ‘081 lb., and 
therefore in terms of foot-pounds, and still assuming that the specific 
heat at constant volume is constant, equation (2) becomes, 
JQ = 081 JK, (change of temperature) + Z. 
02 
