Page:Pyrotechnics the history and art of firework making (1922).djvu/218

 CHAPTER VI

COMPOUND FIREWORKS (continued)

Ruggieri's next class (fireworks turning vertically) includes the following:

1. Revolving Suns. These are merely vertical wheels; he appears to use this term for the more ambitious pieces of this kind.

2. Vertical Wheels. He illustrates a vertical wheel exactly as made to-day under that name. It has, however, been elaborated by the addition of colour cases on the spokes and centre, as rosette and rainbow wheels; also by the application of saxons to the spokes, as saxon wheels.

He also shows the triangle wheel, consisting of three spokes with grooved ends to receive the cases whose sides form the sides of an equilateral triangle. This has been further developed into the double triangle wheel, with two sets of spokes placed one set behind the other. In all the wheels in this class the cases fire in succession, not as in the case of the sun—simultaneously.

Windmills he illustrates as flat bars pivoted in the centre with three cases at either end fired in succession. There also were three, four, and up to eight-armed windmills of the same kind. The nearest device to these of modern times is the chromatrope, the simplest form of which has two bars with a gerb at either end so set as to revolve them in opposite directions, the front one carrying two saxons. This piece, which is of comparatively simple design, gives an extraordinarily fine effect by the intersections of the various streams of fire.

The chromatrope has been developed and enlarged until for important display work quite elaborate pieces are fired