In the next place, the cases, instead of being placed at equal distances upon the perpendicular, may be arranged in pairs, (Fig. 13.) so that each alternate interval may be twice as wide as the next. Or else the direction of the fireworks may be entirely reversed, so as to throw their fires downwards instead of upwards ; or they may be placed horizontally. They may still further be varied, (Fig 10.) by causing a certain number to play upwards, and the remainder downwards, the middle one on each side being horizontal; and this contrivance may also be further varied in two ways, that is, by causing the bottom division to play downwards, and the top one upwards, or the reverse. (Fig. 12.) Although in description these do not seem to differ much, the effects are very dissimilar. It is also a great advantage that so many varieties of form, where variety is so much wanted, can be attained with so little trouble.
The last method of disposing this kind of fire which we shall notice, is where the fires of two cases cross, or start from one point. The cases for this purpose are arrang ed like the teeth of a saw on each side of the perpendi cular, and so that every two neighbouring mouths are together, the effect of which is easily understood. (Fig. 8, 11.) All these varieties of the tree may be modified in various ways, by the addition of blue lights, or of small wheels, or of pointed stars ; but it is scarcely necessary, after the preceding remarks, to give directions about matters so obvious.
Pointed Stars.
As this is one of the combinations of fixed cases, which is perpetually wanted in compound fireworks, it must now be described. It is necessary, to insure re gularity in these, that they should be made in proper patterns, or stands of wood or metal, all regularly cut to one size and disposition of angles. The reason for this care is, that it is generally necessary that a great number should burn together, and when they are not equal the effect is unpleasant. The cases for them may be from an inch and a half to two inches in length, and from a quarter of an inch to three-eighths in diameter, and they must all be driven with the greatest care, so as to burn exactly the same length of time. The com position may be white or blue, and will be found in the table. The wooden frame in which they are to be fastened, must have grooves for their reception, and may be furnished with five or six of these, exactly geome trical. The five-pointed star is most commonly used ; but that with six points is rather more ornamental. There must be a hole in the frame, to admit of the star being nailed to any place where it may be required; and the artist should always be provided with a great number of them ready made, as they are always wanted, and will keep for ever. The common leader of the
whole is fixed round them ready for use, having one loose end by which it may be fastened to any general leader; and in fixing the cases upon the frame, care must be taken that their mouths are sufficiently near to each other to produce the effect of a star in burning.
Where small stars only are required, they may be made with single cases. The case for this purpose must be from an inch upwards in diameter, and of si milar lengths ; and upon it must be marked by a com pass at proper distances the requisite number of points, whether five or six. As many holes must then be bored into the composition, and a leader so disposed as to light the whole at once. These cases should be very thick, to prevent the holes from enlarging during the burning, which would spoil the effect, and if the paper be well soaked in alum water, and the paste made with alum, it will stand any fire without enlarging the ori fice.
Of Suns and Stars.
These may be formed in a great variety of ways, so that we must be content with describing and repre senting a few only of the most remarkable. The frame work necessary for these must consist of wheels, hav ing concentric hoops upon the spokes, for the greater facility of attaching the eases.
A simple star is easily produced by six or more cases radiating from a centre. If the mouths of these arc placed outwards, the centre must be filled by means of a wheel, or some other object, (Plate CCCCLXXI 1 I. Fig. 14 ;) but if it is required that the star should be complete without addition, the mouths of the cases must be in wards, taking care at the same time that all the fires may spring clear of each other. A better star may be formed, (Fig. 15,) by placing six blue lights in short cases alter nately, with as many brilliant ones in long cases, so that they may form two stars together, of different colours and of different diameters. This may be further varied by the introduction of a central light.
Stars more complicated may be made in many differ ent ways. Thus twelve large cases, or more, may be placed on the circle, so as to look outwards, (Fig. 16,) while the same number, or six, of a much smaller size, may be placed on the same circle, either alternately, or at the same points, with their mouths fixed on the cir cumference, and looking inwards. Thus on firing, a double star will be formed, one in the centre of the other. Or else the mouths of the central or inner star may also be collected in the centre, so as to throw their fires outwards in the intervals of the larger star.