A. If the trunnion sight-bracket is correctly adjusted, place the telescopic sight upon it, set the sight and gun at zero elevation, and traverse the carriage to the full limits. If the bubble in the telescope-level remains stationary, the carriage is level. If not, adjust by turning the leveling-bolts.
POWDERS, PROJECTILES, PRIMERS, AND FUSES.
Q. How do you distinguish the following powders: Musket, sphero-hexagonal,[1] brown prismatic, black prismatic, and smokeless.
A. Musket is black and very fine grained. Sphero-hexagonal is black and in the shape of a small ball with a six-sided ring around it. Brown prismatic is brown, in the form of a six-sided prism with a hole in the center. All smokeless powder has the appearance of translucent celluloid and smells of ether. This powder grades in size according to the caliber of the gun, and has for large guns a cylindrical form with small holes running lengthwise in it. (See Fig. 33.)
MUSKET.
SPHERO-HEXAGONAL.
BROWN PRISMATIC.
MORTAR.
SMOKELESS POWDER.
Fig. 33.
Note.—The smokeless powder used in the U. S. Coast Artillery is made out of ordinary cotton waste. The process of manufacture is briefly as follows: The cotton waste is first thoroughly washed, cleaned, picked, and then put through shredding- and cutting-machines. It is then dried in ovens for many hours. It is then placed in pots and a mixture of strong nitric and sulphuric acid is poured over it. It is then washed in running water for many more hours. It is now called "guncotton." It is then dissolved with a mixture of alcohol and ether and put under a hydraulic press. On coming out of the press it looks like yellow gum. It is then forced through different sized dies, and in this shape looks like macaroni. It is then cut into various lengths and sizes, according to the caliber of gun for which it is to be used.