86 Experiments upon Gunpowder. 



As the powder itself is heavy, it may be considered as 

 a weight that is put in motion along with the bullet; 

 and if we suppose the density of the generated fluid is 

 always uniform from the bullet to the breech, the veloc- 

 ity of the center of gravity, of the powder, or (which 

 amounts to the same thing) of the elastic fluid, and the 

 gross matter generated from it will be just half as great 

 as the velocity of the bullet. If therefore we put P to 

 denote the weight of the powder, B the weight of the 

 bullet, and v its initial velocity : then B v -J- |- P v = 

 B -j- ^ P X ^ will express the momentum of the charge 

 at the instant when the bullet quits the bore. 



If now, instead of ascertaining the relation of the ve- 

 locities to the weights of the bullets, we add half the 

 weight of the powder to the weight of the bullet and 

 compute the velocities from the reciprocal sub-tripli- 

 cate ratio of the quantity B -{- P m eac h experiment, 

 the table will stand thus : 



Weight of the Velocity of the Bullet. 



Bullet and Error of 



Experiment. half the Powder. Actual. Computed. the Theory. 



B + f P = 



2352 -\- 72^ 812 812 - 



1754 -j- 72fr 893 8 92 i 



- 7-.\ 1017 ion 6 



603 -|- 72^ 1224 1243 -f- 19 



600 -j- 12 \ 1240 1245 +5 



1288 1449 -|-i6i 



86 25* + 74 '43 1589 + 159 



85 90 -f- 72^ 2109 1999 no 



The agreement between the actual and computed ve- 

 locities is here very remarkable, and particularly in the 

 five first experiments, which are certainly those upon 

 which the greatest dependence may be placed. 



