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 VV 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 lo^th and iO5th experiments, when 

 the piece was fired with 145 grains of government pow- 

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

 tity of double proof * battle powder (experiment N.o. 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. 



With 218 grains of government powder, the mean 

 velocity in four experiments (viz. the 4Oth, 4ist, 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 i^So 2 as i is to 1.2691. 



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

 government powder in the iO9th, i roth, 1 1 ith, and i I2th 

 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; f^ 2 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 tattle 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. 



