Good powder should be devoid of smell, and of uniform colour, approaching to that of a slate. The particles should be perfectly granulated, and free from cohesion. It should admit of being readily poured from one vessel to another.
In powder that has become damp, large lumps are formed: should the damage, however, not be very considerable, these concretions may be reduced by drying the powder in a hot-air stove, rubbing and loosening the grains; but powder thus affected never thoroughly regains its lost strength.
To test the purity of powder.—Lay a dram of it on a piece of clean writing-paper, and fire the heap by means of a red-hot iron wire: if the flame ascend quickly with a good report, leaving the paper free from white specks, and without burning holes in it, the goodness of the ingredients and proper manufacture of the powder may be safely inferred.
Good powder blasted upon a clean plate of copper should leave no track or mark of foulness.
Powder exposed for 17 or 18 days to the influence of the atmosphere ought not to increase materially in weight. One hundred pounds of powder should not absorb more than twelve ounces: if it increase in weight more than one per cent., the powder should be condemned.
Proof of Gunpowder.
To prove the strength of large grain or common powder, 2 ounces are fired from 8-inch Gomer mortars (at an angle of 45°), placed on stone beds, and so fixed as not to recoil. These mortars are loaded with shot weighing 68 pounds, and the average of the ranges, with Government powder of Waltham Abbey, is 250 feet. Powder made of common pit charcoal will only project such a ball, under the same circumstances, about 220 feet; and powder that has been re-stoved will only produce a range of from 107 to 117 feet.
A musket, charged with two drams of fine grained or musket powder, should drive a steel bullet through 15 or 16 half-inch elm boards, placed three quarters of an inch from each other, the first board being set at 40 inches from the muzzle of the musket: with re-stoved powder, the bullet will only perforate from 9 to 12 of the boards.
The quality of large grain powder is ascertained by its general appearance, its firmness, glazing, uniformity of grain, and density.
POWDER MARKS.