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42. What length of time is required to heat them to a red heat?
The shot being placed and the furnace cold, it requires one hour and fifteen minutes; but after the furnace is once heated, a 24-pdr. shot is brought to a red heat in twenty-five minutes; the 32-pdr. and 42-pdr. shot require a few minutes longer.
43. Describe grates for heating shot.
In siege and other batteries, where there are no furnaces, a grate is used. It consists of four bars 1.75 inches square, three feet long, placed four inches apart on three iron stands, one foot in height. It is placed in an excavation one foot in depth, of the width of the grate, perpendicular at the back and side, open in front, the legs resting on bricks or stones rising about four or five inches from the bottom. A roof is made over it with hoops of flat iron, covered with sods and eighteen inches of earth, having in the back part a chimney six inches square. The shot are placed on the back part of the grate, leaving one-fourth of the front part free; and under and on the front part the wood is put, cut in pieces about fourteen inches long and two inches thick. A thick sod is used as a register, to regulate the draught of the chimney, so that no flame can issue from the front. This grate, which will contain about fifteen 24-pdr. balls, heats them to a red heat in an hour, and will supply three guns.
44. How are wads for firing hot shot made?
Of hay; by twisting from the hay a rope of an inch or an inch and a half in diameter, and then commencing at one end, and doubling it up about one calibre in length, twisting it all the time until it becomes nearly large enough, when the rope is wound around the wad perpendicular to its axis, and fastened with a hitch. Or the hay may be rammed in a form of proper calibre, and then bound with spun yarn, and afterwards rammed a second time.
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45. Have hot shot been almost entirely superseded?
Yes, since the adoption of the method of throwing large hollow shot from long pieces. These require but little preparation, can be used at once, and are more terrible in their effects.