THE USE OF FUZES.
324. All spherical shells, except those for the 24 and 12 pdr. howitzer, and all shrapnell, are fitted with the Navy time-fuze.
This fuze is composed of a composition driven in a paper case, and then inserted in a metal stock which screws into a bouching fitted to the shell.
The composition is covered with a safety-cap, which protects it from moisture and accidental ignition; also with a water-cap of peculiar construction, intended to protect the flame from being extinguished on ricochet.
A safety-plug at the lower extremity prevents the communication of fire to the powder in the shell, in the event of the accidental ignition of the fuze after being uncapped.
325. It is strictly forbidden to show or explain to foreigners or others the construction of any fuzes, except so far as may be necessary for the service of the guns.
326. These fuzes are of 3 1/2, 5, 7, 10, 15, and 20 seconds time of burning; which are supposed to offer a sufficient variety for most of the exigencies of service. There are also supplied paper-case fuzes of greater length, which, when used, are always to be inserted in metal stocks.
All the Navy time-fuzes—paper case as well as metal stock—being intended for use under a water-cap, burn a longer time in the open air.
All shells, unless otherwise ordered, are fitted and issued from the shell-houses with the 5-seconds fuze, which is to be regarded as the general working fuze.
For greater or less distances this fuze may be drawn, and any of the others substituted.