WHEELS.
Wheel-cases are made to any length; which must always depend on the size of the wheel, but must not exceed the length of each angle.
| Charge for wheel-cases, from 2 oz. to 4 lb. | ||
| lb. | oz. | |
| Meal-powder | 4 | 0 |
| Saltpetre | 1 | 0 |
| Brimstone | 0 | 8 |
| Charcoal | 0 | 4 |
The filings in this composition may be varied by using a portion of sea-coal, glass-dust, saw-dust, &c., or a combination of the whole.
SLOW FIRE FOR WHEELS.
| lb. | oz. | |
| Saltpetre | 0 | 4 |
| Brimstone | 0 | 2 |
| Meal-powder | 0 | 1½ |
| or, 1 oz. of brimstone may be used with 1 oz. of antimony. | ||
DEAD FIRE FOR WHEELS.
| oz. | dr. | |
| Saltpetre | 4¼ | 0 |
| Brimstone | 0¼ | 0 |
| Lapis-caliminaris | 0 | 2 |
| Antimony | 0 | 2 |
Single Vertical Wheels.—There are different sorts of vertical wheels; some having their fells of a circular form, others of an hexagonal, octagonal, or decagonal form, or of any number of sides, according to the length of the cases you design for the wheel; the spokes being fixed in the nave, nail slips of tin, with their edges turned up so as to form grooves for the cases to lie in; form the end of one spoke to that of another; then tie the 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; as they will, if made by the following directions: In all the cases of both wheels, except the first, on each wheel drive two or three ladlesful of slow fire, in any part of the case; but be careful to ram the same quantity in each case; and in the end of one of the cases, on each wheel, you may ram one ladleful of dead-fire composition, which must be very lightly driven; 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. 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 14 or 16 inches diameter, which is the proportion generally used. The best wood for wheels of all sorts is a light and dry beech.