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.ooo 4 .f __ y^ d ec j ucec i 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 

 4*68' - lS72 =y=. 1479.5; 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 y expressed in atmospheres, as shewn by the 

 experiment, by the number here found indicating its 

 value, as determined by computation. 



It is therefore y^W^ 6-3744 for the value of this 

 coefficient ; and this multiplied into the number 1479.5 

 gives 9431 for the value of 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 iooo 1 + ' 4 jj/ = 

 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 



