A Manual of Pyrotechny; or, A Familiar System of Recreative Fire-works

by G. W. Mortimer

To purify Sulphur.

3. To purify Sulphur.—Melt a quantity of it in an iron pan, by which means the earthy and metallic parts will be precipitated, and then pour it into a copper-kettle, where it will form another deposit of the impure matter with which it is mixed; after keeping it for some time in a melted state, pour it into cylindric wooden moulds, for the purpose of forming it into sticks; the moulds may be about an inch in diameter; their length may be various. If the sulphur should take fire during this operation it may be quickly extinguished by covering the pan close over at the top.

Charcoal.

4. Charcoal is also a considerable ingredient in our compositions, but is of a much more simple nature than that of the foregoing ones. It may generally be procured at the hardware shops, or at foundries, or it may be easily prepared, for which put a quantity of small pieces of wood, such as beech or alder, into a large earthen or iron pot, filling up the vacuities, and covering the top with sand; then placing the pot in the middle of a strong fire, and keeping it at a red heat for two or three hours, as the sand excludes the air, the wood is thus reduced to charcoal without the possibility of its being consumed; and when the pot is cold, the charcoal is to be taken out and kept for use in some very dry place. Small quantities should only be made at a time, as it is always best newly prepared.

Steel-dust.

5. Steel-dust is another important ingredient in fire-works, for being mixed with mealed powder or some other composition, and the mixture inflamed in a proper tube, or case, the jet of fire produces a most brilliant appearance by the sparks arising from the ignition of the iron in the oxygen gas of the nitre.

Iron-filings, (for this Steel-dust is nothing more than pure iron reduced into small particles by filing or some other method,) when free from rust, and not mixed with any impurities, answer very well; but fire-work makers generally prefer cast-iron reduced to powder, by beating thin plates of it on a cast-iron anvil with a heavy hammer, and sifting the broken particles through sieves of brass or iron wire, of different degrees of fineness, so as to separate the particles into grains of various sizes, according to the magnitude of the pieces. The grains thus sorted have been called iron-sand, and have been distinguished into sand of three or four orders, according to their respective fineness; thus the sand that passes through the finest sieve, is called sand of the first order; and that which passes through the second, sand of the second order; and so on to the fourth, which is generally very coarse. The finest is calculated for fire-works of the smallest size, the second for pieces somewhat larger, and that of the last order, only for pieces of the largest size, such as gerbes of six or eight pounds, the composition of which being of proportionate strength to bring such large particles into a state of ignition.

As these grains are very apt to rust by keeping, they should be preserved either in close stopped bottles, well dried, or in boxes that shut close, and are lined with paper moistened in linseed oil. It sometimes happens that fire-works may be required to be kept a long time, or sent abroad; neither of which could be done with the brilliant fires, if made with filings unprepared, for this reason, that the salt-petre being of a damp nature it causes the iron to rust; the consequence of which is, that when the works are fired there will appear but very few brilliant sparks, but instead of them a number of red and drossy sparks; and besides, the charge will be so much weakened that if this were to take place in wheels, the fire would scarcely be strong enough to force them round; but to prevent such failures in the firing of them, the filings, or iron-sand, may be thus prepared:—

To prepare Iron-sand.

6. To prepare iron-sand.—Melt in a glazed earthen pan some brimstone over a slow fire, and when melted throw in some filings, which keep stirring till they are all covered with brimstone, this must be done while it is on the fire; then take it off and stir it very quickly till cold, when it must be rolled on a board with a wooden roller, till broken as fine as corned powder, after which sift from it as much of the brimstone as possible.