Trigger-springs—Small springs to keep the triggers constantly pressing close to scear.
Tumbler—The moveable centre piece of a lock, which falls with the cock.
Tumbler-screw—The screw which fastens on the cock.
Vent-hole—A small hole at the side of the breeching in detonating-guns, to let out the gas, and lessen the recoil.
Worm—Screw at the end of ramrod.—Hints to Sportsmen—Thornton—Daniel—Hawker—Wild Sports.
Gunpowder, s. The powder put into guns to be fired.
Gunpowder is composed of very light charcoal, sulphur, and well refined saltpetre. The powder used by sportsmen in shooting game is generally composed of six parts of saltpetre, one of charcoal, and one of sulphur; but these proportions, as well as the introduction of other ingredients, and the sizes of the grains, are undoubtedly varied by the different manufacturers in the composition of the powders of the same denominations, and are always kept profoundly secret.
The materials are put into a wooden trough, where they are ground together, to render the contact of the nitrous and combustible particles intimate and equal throughout the whole mass. The mixture is occasionally sprinkled with water to form an amalgam, which is afterwards granulated, and to prevent the finer particles of the sulphur and the charcoal from flying off, which would necessarily alter the proportion of the composition. The powder-makers employ more or less time in the operation of grinding, in proportion to the quantity and quality of the saltpetre. When they conceive that the ingredients are properly mixed together, they from the paste form these little grains, which, being dried, obtain the name of gunpowder.
There are two general methods of examining gunpowder, one with regard to its purity, the other with regard to its strength.
Its purity is known by laying two or three little heaps near each other upon white paper, and firing one of them. For if this takes fire readily and the smoke rises upright, without leaving any dross or feculent matter behind, and without burning the paper, or firing the other heaps, it is esteemed a sign that the sulphur and nitre were well purified, that the coal was good, and that the ingredients were thoroughly incorporated together; but if the other heaps also take fire at the same time, it is presumed, that either common salt was mixed with the nitre, or that the coal was not well ground, or the whole mass not well beat or mixed together; and if either the nitre or sulphur be not well purified the paper will be black or spotted.