To make Wheels and other Works incombustible.
It being necessary, when your works are new, to paint them of some dark colour; therefore, if instead of which, you make use of the following composition, it will give them a good colour, and in a great measure prevent their taking fire so soon, as if painted. Take brick-dust, coal ashes, and iron filings, of each an equal quantity, and mix them together, with a double size, made hot. With this wash over your works, and when dry wash them over again; this will preserve the wood greatly against fire. Let the brick-dust, and ashes, be beat to a fine powder.
Of Single Vertical Wheels.
There are different sorts of vertical wheels, some having their fells of a circular form, others of an hexagon, octagon, or decagon form, or any number of sides, according to the length of the cases, you design for the wheel: your spokes being fixed in the nave, nail slips of tin, with their edges turned up, so as to form grooves for the cases to ly in, from the end of one spoke to another; then tie your cases in the grooves, head to tail, in the same manner as those on the horizontal water wheel, so that the cases successively taking fire from one another, will keep the wheel in an equal rotation. Two of these wheels are very often fired together, one on each side of a building, and both lighted at the same time, and all the cases filled alike, to make them keep time together, which they will do if made by the following directions. In all the cases of both wheels, except the first, on each wheel, drive two, or three ladles full of slow fire, in any part of the cases, but be carefull to ram the same quantity in each case, and in the end of one of the cases, on each wheel, you may ram one ladle full of dead fire composition, which must be very lightly drove; you may also make many changes of fire, by this method.
Let the hole in the nave of the wheel be lined with brass, and made to turn on a smooth iron spindle. On the end of this spindle let there be a nut, to screw off and on; when you have put the wheel on the spindle, screw on the nut, which will keep the wheel from flying off. Let the mouth of the first case be a little raised. See [fig. 39.] Vertical wheels are made from ten inches to three feet diameter, and the size of the cases must differ accordingly; four ounce cases, will do for wheels, of fourteen, or sixteen inches diameter, which is the proportion generally used. The best wood for wheels of all sorts, is a light, and dry beech.
Of Horizontal Wheels.
Horizontal wheels are best when their fells are made circular; in the middle of the top of the nave, must be a pintle, turned out of the same piece as the nave, two inches long, and equal in diameter to the bore of one of the cases of the wheel; there must be a hole bored up the center of the nave, within half an inch of the top of the pintle; the wheel being made, nail at the end of each spoke (of which there should be six or eight) a piece of wood, with a groove cut in it to receive the case. These pieces fix in such a manner, that half the cases may incline upwards, and half downwards, and that when they are tied on, their heads and tails may come very near together; from the tail of one case, to the mouth of the other carry a leader, which secure with pasted paper. Besides these pipes, it will be necessary, to put a little meal powder inside the pasted paper, in order to blow off the pipe, that there may be no obstruction to the fire, from the cases. By means of these pipes, the cases, will successively take, burning one upwards, and the other downwards. On the pintle, fix a case of the same sort as those on the wheel; this case must be fired by a leader, from the mouth of the last case on the wheel, which case must play downwards: instead of a common case in the middle, you may put a case of Chinese fire, long enough, to burn as long as two or three of the cases on the wheel.
Plate. 3