The sole difference between a turning sun and a girandole is in the position at the time of discharge. The sun is placed vertically, while the girandole has its plane parallel to the horizon. A turning sun is a wheel, which is caused to revolve by the discharge of one or more rockets attached to it. These operate with the same expenditure of force as when they make a free ascension, with the same action of gases from combustion against the resistance offered by the inertia of the air. (PL VIII, fig. 3.)
A wheel may be equipped with 20 rockets or even with a larger number. But, to secure the revolution of the wheel, four of the rockets must be discharged simultaneously. For example, the first, sixth, eleventh, and sixteenth may be fired together, and these, on finishing, will give their fire to the second, third, twelfth, and seventeenth; and the like method should be followed in the discharge of the remaining rockets. The effect is that the wheel, although equipped with 20 rockets, has only five separate periods of discharge. The fire is communicated from the end of one to the throat of another by means of a fuse, over which a strip of paper is pasted from one rocket to another.
Ordinary paper is not fitted to withstand the action of Chinese fire. It is penetrated too quickly by the iron sand in fusion. A double strength of paper is required. This is secured by pasting together two sheets, using a paste made from potter's clay.
Two methods are followed in placing the jets on the wheel in such a manner that it shall be made to revolve. One is to attach one or more jets on the rim of the wheel, in such a position that they spurt their fire from the throat. The other method is by fastening them on the spokes of the wheel in the direction of their length. In this instance, they spurt their fire, not by way of the throat, but from a lateral orifice, which is pierced with a gimlet in the body of the rocket, a little below the plug that closes the opening of the throat. A description of such lateral holes has been given in connection with table rockets.
Each hole should have a diameter one-quarter that of the interior diameter of the jet. When only one or two jets are used, it is preferable to attach them to a tourniquet having either one or two arms. But when three, four, or five jets are employed, they are mounted on a wheel having an equal number of spokes. A larger number of jets may be carried, by the use of hoops in the manner described above for fixed suns. (Pl. VI, figs. 1, 2, and 3.)
A third method of making girandoles allows the small jets to turn the piece. The advantage of this is that, after the motion has been begun, various garnitures may be discharged. The body of this machine consists of a wooden tube of a length proportioned to the base that is to be used, ordinarily 9 inches. It is closed at the top by an iron disc, in the middle of which there is a small opening to receive the point of the pivot on which the piece is to turn. Three screw holes are made in the central part of the tube at equal distances from one another, into each of which is screwed a jet carrier, made from two pieces of wood having the form of a T. This carrier supports a jet which is laid along the crosspiece of the T, where it is securely tied. A port fire runs from one to another of these jets, arranged in such a manner that the first one in finishing gives fire to the second, and this in turn to the third. (PL X, figs. 13 and 14.)
The firework, when the garniture has been completed, is set on a pointed rod of iron, which serves as the pivot about which it revolves.
The tube may be equipped with two or three rows of jets, each row numbering three, four, or five jets. When the rows are of more than three jets, since the circumference of the tube is not sufficient to allow the placing of more than three holes in a horizontal plane, the holes are pierced underneath, one a little higher, the next a little lower; and this process is repeated for the necessary number of times. It is also possible, by placing the jets of the second row opposite those of the first, to cause the piece, after having turned to the right, to return to the left.
Ordinarily, there are added to the garniture of this firework a number of jets placed upright, which cast their fire vertically upward, or at any angle desired. These offer a contrast to the fire thrown from the jets at a right angle to the upright of the T.
Turning suns and girandoles serve in the making of a great variety of pieces, among which the commonest are the following:
Figure 1: This is formed from two wheels, each garnished with 12 jets arranged in three groups, which turn in opposite directions on the same axis. Within each wheel is contained another wheel, having iron cogs that engage in a pinion wheel common to the two larger wheels. The engagement serves to regulate the movement, so that neither shall turn more quickly than the other. Four jets on each wheel are discharged at the same time, and the fires from these, crossing, form the special effect.
Figure 2: This firework is formed by placing turning suns within an open-fronted box behind cardboard frames. The box contains the fires so that they are seen only within the frame. This device is extremely effective for decorative purposes.
Figure 3: A turning sun is placed within a wooden receptacle having a star-shaped opening in the front. Thus, when discharged, the fire shows the form of a star. Or any other desired shape may be used at will. Usually, such a star is equipped with six girandoles, made from tourniquets of two jets set in each point of the star. These are discharged at the same time, and their combined effect is to form a hexagonal figure bordering the star. A good contrast is afforded by having a star of Chinese fire, with the inclosed girandole of the ordinary mixture.
The jets with which turning suns are garnished should be charged solidly on a base carrying a spindle, and choked.
A sun of five rays is ordinarily garnished with jets that are loaded with Chinese fire for the first discharge, with common fire for the second, with white fire for the third, with new fire for the fourth, and with red Chinese fire for the fifth. To increase the effect, each jet may be loaded half with one fire and half with another.
The force of the composition should be proportionate always to the size of the jets, just as their size should be proportioned to the size of the wheel which they cause to turn. The force of the composition should be either di-minished or increased, according as the jets are larger or smaller.