The pipes of communication which are used under water, must be made of thick paper, and when dry covered with drying oil, which must then be thoroughly dried. In oiling them leave about one and a half inches dry for joints; as the parts would not adhere where the oil was applied. The whole, however, is completely oiled after the leaders are joined, and the paste dry. These pipes will remain under water for some time without injury.
Sec. III. Of Horizontal Wheels for Water.
An octagon wheel is to be provided, made of flat boards eighteen inches in diameter, so that the length of each size will be near seven inches. In all the sides, cut a groove for the cases to lie in. Procure a wooden bowl without a handle, and on the top nail the wheel; then take four eight-ounce cases, filled with a proper charge, each about six inches in length. When the wheel is to be clothed with these cases, get some whitish-brown paper, and cut it into slips of four or five inches broad, and seven or eight long. These slips being pasted all over on one side, take one of the cases, and roll one of the slips of paper about one and a half inches on its end, so that there will remain about two and a half inches of the paper hollow from the end of the case. This case is to be tied on one of the sides of the wheel, near the corners of which holes must be bored, through which the pack thread is put to tie the cases. Having tied on the first case at the neck and end, put a little meal-powder in the hollow paper; then paste a slip of paper on the end of another case, the head of which put into the hollow paper of the first, allowing a sufficient distance from the tail of one to the head of the other for the pasted paper to bend without tearing. The second case is to be tied on in the same manner as the first, and so on with the rest except the last, which must be closed at the end; unless it is to communicate to any thing on the top of the wheel, such as fire-pumps, or brilliant fires, fixed in holes cut in the wheel, provided they be not too heavy for the bowl.
Before the cases are tied on, the upper part of all their ends except the last should be cut shelving, that the fire from one may play over the other, without being obstructed by the case. Wheel cases have no clay driven in their ends, nor are they pinched, but always left open; only the last, or those which are not to lead fire, which must be well secured.
Sec. IV. Of Water Mines.
A bowl and wheel, as above described, are necessary for this exhibition; but with this difference that in the wheel there must be a hole large enough to receive the mine. These mines are tin pots, with strong bottoms, and a little more than two diameters in length. The mine must be fixed in the hole in the wheel, with its bottom resting on the bowl; then loaded with serpents, crackers, stars, small water rockets, &c. in the same manner as pots of aigrettes; but in the centre fix a case of Chinese fire, or a small gerbe, which must be lighted at the beginning of the last case on the wheel. These wheels are to be clothed as usual.
Sec. V. Of Fire Globes for the Water.
Bowls for water globes must be very large, and the wheels on them of a decagon form. On each side of the wheels, nail a piece of wood four inches long; and on the outside of each, cut a groove, wide enough to receive about one-fourth of the thickness of a four-ounce case. These pieces of wood must be nailed in the middle of each face of the wheel, and fixed in an oblique direction; so that the fire from the cases may incline upwards. The wheel being thus prepared, tie in each groove a four-ounce case, filled with a gray charge. Then carry a leader from the tail of one case to the mouth of another.
Globes for these cases are made of two tin hoops, with thin edges outwards, fixed one within the other, at right angles. The diameter of these hoops must be somewhat less than that of the wheel. Having made a globe, drive in the centre of the wheel, an iron spindle, which must stand perpendicular, and be in length four or six inches more than the diameter of the globe.
The spindle serves as an axis, on which the globe is fixed, which, when done, must stand four or six inches from the wheel. Round, on one side of each hoop, must be soldered small bits of tin, two and a half inches distant from each other. These pieces must be two inches in length each, and only fastened at one end, the other ends being left loose, on which to turn round the small port-fires, to hold them on: These port-fires must be made of such a length, as will last out the cases on the wheel. There need not be any port-fires at the bottom of the globe, within four inches of the spindle; for, if there were, they would have no effect, but only burn the wheel. All the port-fire must be placed perpendicular from the centre of the globe, with their mouths outwards; and must all be clothed with leaders, so as all to take fire with the second case of the wheel; which cases must burn two at a time opposite to each other. When two cases of a wheel begin together, two will end together; therefore the two opposite end cases must have their ends pinched, and secured from fire. The method of firing such wheels is, by carrying a leader from the mouth of one of the first cases to that of the other; which leader, being burnt through the middle, will give fire to both at the same time.