TO GIVE MOTION.
Jet of Fire.—Prick various sized holes at unequal distances apart in a band of paper, but few in one part, others thinly scattered, others profusely sprinkled, to represent the sudden bursts of sparks. This band is to ascend between a light and the jet made on paper as above.
Cascade.—The same perforated band is to move downwards instead of upwards, which is done by making the band wind off one roller as another winds it on.
Fig. 134.
Globes, Columns, Pyramids.—The band of paper cut out in apertures inclined at a somewhat different angle from that of their spirals, must move upwards vertically. Thus the fire will seem to be continually ascending along these spirals, and the machine will appear to revolve with them.
Suns.—These are more difficult, as you must picture fire proceeding from the centre to the circumference. On strong paper describe a circle a little larger than the surface of your sun. On this trace two spirals, one-twelfth of an inch apart, and open the intervening space with a knife, cutting the paper from the circumference, decreasing in breadth to a certain distance from the centre. Then cut the remainder of the circle into similar spirals, alternately open and close. Paste it on an iron hoop, supported by an iron cross, and set all on a stand which will let it freely turn round its centre.
Fig. 135.
Fig. 136.
On placing this between a light and your sun, and moving it towards that side to which the convexity of the spiral is turned, the opening will give, on the image of the sun’s rays or jets of fire, the appearance of fire continuously flowing from the centre to the circumference.