GRAPE-SHOT, in artillery, is a combination of small shot put into a thick canvas bag, and corded strongly together, so as to form a kind of cylinder, whose diameter is equal to that of the ball which is adapted to the cannon.
To form grape-shot, a bag of coarse cloth is made just to hold the bottom which is put into it, then as many shot as the grape is to contain; and with a strong pack-thread they are quilted, to keep the shot from moving; and when finished they are put into boxes for carriage, to be transported wherever it is necessary.—The number of shot in a grape varies according to the service or size of the guns. In sea-service the number is always nine; but by land it is increased to any number or size, from an ounce and a quarter in weight. It has not yet been determined with any accuracy, what number or size best answers in practice; for they often scatter so much, that only a small number take place.
Proper charges for grape-shot have never yet been effectually determined. From some experiments, however, it appears, that for heavy six-pounders one third of the weight of the shot appears to be the best charge of powder; for the light six-pounders, one fourth of the weight of the shot; and, for howitzers, one eighth or one tenth answers very well.
This kind of fire seems yet not to have been enough respected or depended on. However, if cannon and howitzers can be made to throw one third or one fourth of their charge into a space of 39 X 12 feet, at 200 and 300 yards distance, and those fired ten or twelve times in a minute, it surely forms the thickest fire that can be produced from the same space.