The sudden change of this piece is very pleasing, and gives great surprize to those who are not acquainted with the contrivance. A wheel for this purpose should be about three feet diameter, and its fell circular, on which tie sixteen half pound cases filled with brilliant charge; two of these cases must burn at a time, and on each end of the nave must be a tin barrel of the same construction as those on the regulated piece; the wheel being compleated, prepare the post or stand after the following manner: first have a stand made of any height, about three or four inches square, then saw off from the top, a piece two feet in length; this piece join again at the place where it was cut, with a hinge on one side, so that it may lift up and down in the front of the stand, then fix on the top of the bottom part of the stand, on each side a bracket; these brackets must project at right angles with the stand, one foot from the front, for the short piece to rest on; but these brackets must be placed a little above the joint of the post, so that when the upper stand falls, it may lay between them at right angles with the bottom stand, which may be done by fixing a piece of wood, one foot in length, between the brackets and even with the top of the bottom stand; then, as the brackets rise above the bottom stand, they will form a channel for the short post to lay in, and at the same time keep it steady without straining the hinge: on the side of the short post opposite the hinge, nail a piece of wood; this piece must be of such a length, that, when the post is perpendicular, it may reach about one foot and a half down the long post, to which being tied, it will hold the short stand upright; the stand being thus prepared, in the top of it fix a spindle ten inches in length; on this spindle put the wheel, then fix on a brilliant sun with a single glory; the diameter of this sun must be six inches less than that of the wheel. When you fire this piece, light the wheel first, and let it run horizontally till four cases are consumed; then from the end of the fourth case carry a leader into the ten barrel that turns over the end of the stand; this leader must be met by another brought through the top of the post, from a case filled with a strong port-fire charge, and tied to the bottom post, with its mouth facing the pack-thread which holds up the stand, so that when this case is lighted, it will burn the pack-thread, and let the wheel fall forward, by which means it will become vertical; then from the last case of the wheel, carry a leader into the barrel next the sun, which will begin as soon as the wheel is burnt out. Of the grand Volute illuminated with a projected Wheel in Front.