ROCKETS, LINE.
Any rocket which is not very large, may be made to run along an extended rope. For this purpose affix to the rocket an empty case, and introduce therein the rope which is to carry it, placing the head of the rocket towards that side to which it is intended to move. Two rockets with an empty case may be similarly used, and may be made to move in a retrograde direction by placing them with their heads reversed, and a leader to communicate from the head of the rocket to be first ignited to the tail of the second.
ROCKETS, SIGNAL.
Composition.
Pulverized saltpetre, 4 lb.; sublimated sulphur, 1 lb.; dogwood charcoal, 1 lb. 8 oz.
The charcoal is first pounded fine enough to pass through a wire sieve (No. 3). The saltpetre and sulphur are each separately passed through a fine hair sieve, then mixed well together with a copper slice, and passed three times through the hair sieve. The charcoal is then spread on a tray, and the saltpetre and sulphur sifted a fourth time on it, and the whole being carefully mixed with a hard brush, is afterwards passed four times through the wire sieve.
To each ladleful of composition, 25 blows are given for the pound, and 21 for the half-pound rocket.
Twenty-eight ladlesful of composition (7½ oz.) are required to complete the pound, and twenty-five (5 oz.) the half-pound rocket.
To prevent accidents in driving rockets, &c., the workman should keep his body erect, the drift being well cleaned after each ladleful; and while driving, it should be moved backward, and forward by a pair of holders.
Rockets are driven 3½ calibres hollow, 1 calibre solid, and ½ calibre with clay.