The well-known pyrotechnical preparation, but modified to suit various purposes. A cylindrical case charged with a fiercely burning composition, the gases of which, rushing out from the after-end against the resisting atmosphere, propel the whole forward at a rate continually increasing, until the composition be expended. It is generally kept in balance by a long light stick or tail attached. The case is made of metal or paper, and variously headed to the amount of 32 lbs. if its purpose be war (see congreve-rocket); life-saving (by conveying a line over a stranded vessel); even the killing of whales, when reduced to 1, 2, or 3 lbs.; or, lastly, signals, for which it is fired straight upwards.