Caprices are so called from the particular motion they assume, and are regulated according to the order and manner of their firing.
A perpendicular shaft, or post, is first provided, in which are placed two sets of spokes at some distance from each other. At the extremities of these spokes, joints are made, on which the cases are fixed. These cases communicate with each other by leaders. The first which takes fire, discharges upwards; the second, vertically; the third, horizontally; and the fourth, fifth, sixth, and seventh, go off at the same time; viz. the fourth, upwards; the fifth, vertically, a little inclined; the sixth, horizontally; and the seventh, vertically. The match of communication is fixed by a port-fire.
The arrangement of this piece, to produce the effect, depends on the construction of the wood work.
The great falling caprice differs from the foregoing in the following particular, that it separates itself in the midst of its fire into three parts. It is formed of three wheels, which appear as one; but at a certain time after the fire is communicated, they separate and occupy certain positions.
Mercury's Wand, as it is called, is formed by placing, across each other, two pieces of wood, and at the extremity of each four lances parallel to each other, and one obliquely. These lances of illumination must be connected by leaders. Circular bands are attached to the extremity of each leg, which terminates in the centre, and the wings or legs move in opposite directions. The double crescents, thus formed, produce, in turning, a variety of figures.
Sec. IX. Of Palm and other Trees.
The representation of trees is considered an elegant fire-work. Palm trees are shown by fixing an upright piece, which serves as a trunk, and attaching to it a number of pieces, resembling in effect the branches of a tree. The extremities or branches are decorated with gerbes, and sometimes with marrons, arranged in such a manner that they may go off together.
For Yew trees, cases of brilliant fire, jessamine, or Chinese are used. In making this representation, the upright piece is usually four feet in length, two inches in breadth, and one inch thick. At the top we fix, on the flat side, a hoop fourteen inches in diameter, and round its edge and front, place illuminations, and in its centre a five-pointed star. At a foot and a half from the edge of the hoop, two cases of brilliant fire are usually placed, one on each side. These cases should be one foot long each. Below these are usually fixed two more cases, at such a distance that their mouths may almost meet those at top. Two other cases are sometimes added, which ought to be parallel with the last. The cases are then clothed with leaders, so that they, with the illuminations and stars at top, may all take fire together.
Fire trees may be formed by placing cases at an angle of 45 degrees, inclining upwards from the trunk, and at certain distances from each other. The two last cases may incline downwards. Cases may also be placed on the trunk itself, so that the whole will resemble a body of fire. Fire trees are commonly made about six feet long and three inches in diameter. The cases are generally fixed to pegs. At the top of the tree, a four-inch mortar is fixed, which is loaded with stars, rains, or crackers. In the middle of this mortar, we may place a case filled with any sort of charge, which must be fired with the other cases. Brilliant fire is generally employed. The fire is communicated, as in other works, by means of leaders, which are fired at the bottom.
There is also another exhibition often made with the so called illuminated yew-tree. The middle piece or stem on which the branches are placed, is generally eight feet six inches high. The branches all incline downward, and shorten as they go up. The number of branches on each side is six, and their length is determined according to judgment. When the branches are fixed, place illuminating port-fires on the top of each, as many as are required. Behind the top of the stem, fasten a gerbe or fountain of Chinese fire, which must be fired at the beginning of the illuminations on the tree.