POWDER AND SHOT. 23 



and are separated in the shape of powder. The success of the 

 experiment of firing a tallow candle through a deal board would be 

 explained in the same manner, by supposing the velocity of a wave 

 propagated through deal to be greater than that of a wave passing 

 through tallow * 



Many sportsmen regularly institute experiments to try the 

 strength of their powder. The chief circumstance relative to the 

 goodness of powder generally arises from the quality of the nitre 

 in its composition. This _ chemical ingredient haying a strong dis- 

 position for absorbing moisture from the air, requires that it should 

 be rendered as pure as possible. It is often mixed with common 

 salt, and this is very injurious to the powder. In all good powder 

 its expansive force is in proportion to the quick communication of 

 the fire through its entire mass. This is the principle that regu- 

 lates its fitness for sporting purposes. 



The method of trying powder instituted and followed at present 

 by the Board of Ordnance, is as follows. The triers first take out 

 ot' the several barrels of gunpowder a measure-full, of about the 

 size of a thimble, which is spread upon a sheet of fine writing- 

 paper, and then iked. If the inflammation be very rapid, the smoke 

 rises perpendicular ; and if the paper be neither burned nor spotted, 

 it is then judged to be good powder. Then two drachms of the 

 same powder are exactly weighed and put into an epruevette,^ 

 which, if it raises a weight of twenty-four pounds to the neight of 

 three inches and a half, is received into the Government magazine 

 as proved. 



This powder trier just mentioned, called an epruevette, may be 

 seen in many gunsmith's shops. It does not, however, test the 

 power of the explosive substance with very great nicety, but still it 

 is a useful instrument, because it furnishes the sportsman with a 



general idea on the subject, which enables him in many cases to 

 etect a bad and impure commodity. 



The following observations on powder by the OaUeigli SJiooting 

 Club are entitled to notice: — "The Dartford gunpowder bought 

 from one retailer will fire smart and strong, while a similar article 

 obtained from another wiU be comparatively weak and_ slow of 

 ignition. This difference in the quality of powder is occasioned by 

 exposure to different atmospheres. Gunpowder is generally pur- 

 chased by the shooter at a provincial town at some distance n-om 

 the manufacturers. One shop or warehouse is dry; another is 

 damp. One package of ]^owder may have lam. only twenty-four 

 hours in the front boot oi the London mad, in July, to the immi- 

 nent danger of the cigar-whiffer on the coach-bpx; another may 

 have been sweating three weeks in a canal-boat, in March ; hence 

 the various degrees of liabihty to imbibe moisture befpre the 

 powder comes into the retailer's possession, and while in his keep-^ 

 mg. Damp not only affects the mtre, of which gunpowder is chiefly 

 composed, and thereby occasions loss of strength ; but it also ope- 



* See Babbage'a "Economy of Machinery." 



