OPTICAL FIREWORKS.
A Gerb of Fire.—On white paper draw the figure of a gerb of fire, lay it on quite opaque paper, black on both sides, and with a very sharp penknife cut several slashes at unequal intervals from the gerb centre; pierce these breaks with holes to represent the sparks. The lines and holes both paint the effect of burning powder issuing from a small aperture.
Fig. 133.
Globes, Pyramids, or Revolving Columns.—Draw the outlines on paper, and cut them out in a helical or spiral form. For the various tints, paste coloured transparent paper at the back.