1 38 Expsriments to determine 



In this table, which does not stand in need of any 

 particular explanation, may be seen the results of all 

 these investigations. 



The dimensions of the barrel made use of in the ex- 

 periments mentioned in this table were as follows : — 



Diameter of the bore at its muzzle = 0.25 of an inch. 



Joint capacities of the bore, and of its vent tube, ex- 

 clusive of the space occupied by the leathern stopper = 

 0.08974 of a cubic inch. 



Quantity of powder contained by the barrel and its 

 vent tube when both were quite full (exclusive of the 

 space occupied by the leathern stopper), 25.641 German 

 apothecary's grains, = 24^ grains Troy. 



The capacities of the barrel and of its vent tube were 

 determined by filling them with mercury, and then 

 weighing in the air, and in water, the quantity of mer- 

 cury required to fill them ; and the quantity of powder 

 required to fill the barrel and its vent tube was deter- 

 mined by computation, from the known joint capacities 

 of the barrel and its vent tube in parts of a cubic inch, 

 and from the known specific gravity of the powder used 

 in the experiments. 



Thus the contents of the barrel and its vent tube 

 having been found to amount to 0.08974 of a cubic inch, 

 and it having been found that i cubic inch of the gun- 

 powder in question, well shaken together, weighed just 

 272.68 grains Troy, this gives 24.47 grains Troy 

 (= 25.641 grains German apothecary's weight) for the 

 contents of the barrel and its vent tube. 



The numbers expressing the charges of powder in 

 thousandth -parts of the joint capacities of the barrel and 

 of its vent tube were determined from the known quan- 

 tities of powder used in the different experiments, ex- 



