Experiments upon Gunpowder. 73 



charges, therefore, must be as the squares of the veloci- 

 ties, and consequently the charge of the weaker powder 

 must be to that of the stronger, when the velocities are 

 equal, as W is to vv. The weaker powder is therefore 

 as much worse than the stronger as VV is greater than 

 vv ; or the comparative goodness of powder of differ- 

 ent degrees of strength is as the squares of the veloci- 

 ties of the bullets, when the charges are equal. 



The mean velocity of the bullets, as shewn by the 

 pendulum, in the 104th and 105th experiments, when 

 the piece v/as fired with 145 grains of government pow- 

 der, was 894 feet in a second; and with the same quan- 

 tity of double proofs battle powder (experiment No. 106), 

 the velocity was 990 feet in a second. Now the squares 

 of these velocities (which, as we just observed, measure 

 the goodness of the powder) are to each other as i is to 

 1.2263, or nearly as 5 is to 6. 



W^ith 218 grains of government powder, the mean 

 velocity in four experiments [viz. the 40th, 41st, 42d, 

 and 43d) was 1225 feet in a second; and in the experi- 

 ment No. 107, when the same quantity of double proof 

 battle powder was made use of, the velocity was 1380 

 feet in a second; and 1225" is to 1380" as i is to 1.2691. 



With 290 grains, or half the weight of the bullet in 

 government powder in the 109th, i loth, 1 1 ith, and 112th 

 experiments, the mean velocity of the bullet was 1444 

 feet in a second ; but with the same quantity of the bat- 

 tle powder (experiment No. 116), the velocity was 1525 

 'feet in a second; 1444'' is to 1525^ as i is to 1.1153. 



By taking a medium of these trials it appears that 

 double proof battle powder is better than government 



* This is called battle powder, not because it is used in battle or in war, but from 

 Battle, the name of a village in Kent, where that kind of powder is made. 



