546 



TRANSACTIONS OF THE AMERICAN INSTITUTE. 



the time being-, must take account of tlie capacities for heat of the entire 

 mixture, and will, therefore, be the quotient of the joint capacity at con- 

 stant pressure, which is 0.20698, by the joint capacity at constant volume 

 0.1854T. This quotient is 1.116 nearly. By substituting this value for v, 

 instead of the former, we obtain results in which the differences are g"en- 

 erally in the right direction, though by no means so great as we should be 

 led to anticipate. These results are exhibited in the following table: 



Mean of pressures 4882 



The mean of the computed pressures, in this table, is somewhat below the 

 assumed pressure, that is to say, the difference is in the right direction but 

 it is not a suflBcient difference. It would produce a mean effect upon 

 velocity equal to,.; y4882=about'one eightieth of the whole. But if we 



V 5007 

 take the time in the gun at Os .006, and admit that the conclusions of 

 Piobert, in regard to the rapidity of combustion are not absurdly in error, 



