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 under this name. Lancework of geometric form is used on the bars or spokes, and the intersection of these, forming ever-changing geometrical designs, adds greatly to the effect of the intersection of the fire.
This effect is the basis of the Guilloché, a somewhat elaborate piece which falls in Ruggieri’s third class. It consisted of six wheels placed one behind the other in pairs of graduated size; the two smallest—which fired first—had six cases, the next eight, and the largest forty-eight, and was twenty feet in diameter.
The next described is the Salamandre, a piece which, on a large scale, is still occasionally fired at the Crystal Palace. It shows a snake in pursuit of a butterfly which it seems to overtake but never quite catches. The mechanism is an endless chain of wooden links running in and out between eight sprocket wheels, arranged in octagon formation. About half the length of the chain is made out and lanced to represent the snake, and a lancework butterfly is situated in the centre of the other half.
Ruggieri claims that his father fired this piece and the guilloché in 1739 at Versailles.
The other pieces mentioned in this section are too elaborate for description in the space available, but are interesting as showing the use of the helix and spiral as applied to wheels and cones, as secondary elements of larger pieces.