to use the lump
brimstone ground, in the same manner as gunpowder.

_Of Saltpetre._

Saltpetre being the principal ingredient in fire-works, and a volatile
body by reason of its aqueous and aerial parts, is easily rarefied by
fire; but not so soon when foul and gross, as when purified from its
gross and earthy parts, which greatly retard its velocity; therefore,
when any quantity of fire-works is intended to be made, it would be
necessary first to examine the saltpetre; for if it be not well
cleansed from all impurities, and of a good sort, your works will not
have their proper effect.

_To pulverize Saltpetre._

Take a copper kettle, the bottom being spherical, and put into it
fourteen pounds of refined saltpetre, with two quarts or five pints of
clean water; then put the kettle on a slow fire, and when the
saltpetre is dissolved, if any impurities arise, skim them off, and
keep constantly stirring it with two large spatulas, till all the
water exhales; and when done enough, it will appear like white sand,
and as fine as flour; but if it should boil too fast, take the kettle
off the fire, and set it on some wet sand, which will prevent the
nitre from sticking to the kettle. When you have pulverized a quantity
of saltpetre, be careful to keep it in a dry place.

_To prepare Charcoal for Fire-works._

Charcoal is a preservative, by which the saltpetre and brimstone are
made into gunpowder, by preventing the sulphur from suffocating the
strong and windy exhalation of the nitre. There are several sorts of
wood made use of for this purpose; some prefer hazel, others willow,
and others alder. The method of burning the wood is this: cut it in
pieces of two or three feet long, then slit each piece in four parts;
scale off the bark and hard knots, and dry them in the sun, or in an
oven; then make in the earth a square hole, and line it with bricks,
in which lay the wood crossing one another, and set it on fire; when
thoroughly lighted, and in a flame, cover the whole with boards, and
fling earth over them close, to prevent the air from getting in, yet
so as not to fall among the charcoal; and when it has lain thus for
twenty-four hours, take out the coals and lay them in a dry place for
use. It is to be observed, that charcoal for fire-works must always be
soft and well burnt, which may be bought ready done.

_Of Gunpowder, &c._

Gunpowder being a principal ingredient in fire-works, it will not be
improper to