[Illustration: Fig. 120.]
Well mix in two ounces of spirits of wine half a drachm each of nitrate
of baryta, nitrate of copper, chloride of copper, and nitrate of
strontian. Put this liquid in a strong metal globe, holding a quarter of
a pint, by an aperture into which screws tightly a small fountain-jet
with a tap. Boil over a spirit-lamp. When the spirit boils, shut off
steam for five minutes. On turning the tap the whole of the spirit will
blow out and spread like a cloud, to which a light being applied, the
whole will become a fiery spray, tinted blue, green, red, yellow, &c.
Perform only in an empty room, where no harm can be done by an
explosion.