the Force of Fired Gunpowder. 155 



were made with that view ; then, from the result of the 

 experiments of which we have just been giving an ac- 

 count (in which 12 grains of powder exerted a force 

 equal to 9431 atmospheres), taking these experiments 

 as a standard, we can, with the help of the theorem 

 ^^T + o.ooo4.r z::! J/) deduced from the former set of ex- 

 periments, compute the initial force of fired gunpowder, 

 thus : — 



The density of the elastic fluid, when 12 grains of 

 powder are used for the charge, being = 468, it is 

 ^ggi.i872__^__ j^y^^^. and in order that this value ofjy 

 may correspond with the result of the experiment, and 

 be expressed in atmospheres, it must be multiplied by a 

 certain coefficient, which will be found by dividing the 

 value of j)/ expressed in atmospheres, as shewn by the 

 experiment, by the number here found indicating its 

 value, as determined by computation. 



It is therefore y^^^y -5 = 6.3744 for the value of this 

 coefficient ; and this multiplied into the number 1479.5 

 gives 9431 for the value oi y in atmospheres. 



Again, the density being supposed = 1000 (or that 

 the charge of powder completely fills the cavity in which 

 it is confined), in that case it will be 1000'"^°'* ^=jk = 

 15,849 ; and this number being turned into atmospheres 

 by being multiplied by the coefficient above found 

 (=6.3744), gives 101,021 atmospheres for the measure 

 of the initial force of the elastic fluid generated in the 

 combustion of gunpowder. 



Enormous as this force appears, I do not think it 

 overrated ; for nothing much short of such an incon- 

 ceivable force can, in my opinion, ever explain in a satis- 

 factory manner the bursting of the barrel so often men- 

 tioned ; and to this we may add, that, as in 7 different 



