Mix gunpowder with a small quantity of water and gum arabic, and with
a brush place it on a screen in the background in an irregular manner,
resembling flashes of lightning. The screen being previously painted
to resemble thunder clouds, let there be a number of distinct flashes
painted, the ends of which should be near the ante-room. At intervals
of thirty seconds, touch a lighted fusee to one of these paintings,
which will burn quickly, illuminate the clouds, and resemble lightning
flashes.