_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.
[Illustration: 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.
[Illustration: Fig. 135.]
[Illustration: 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.