Of The Method Of Mixing Compositions

The performance of the principal part of fire-works depends much on

the compositions being well mixed; therefore, great care ought to be

taken in this part of the work, particularly in the composition for

sky-rockets. When you have four or five pounds of ingredients to mix,

which is a sufficient quantity at a time, (for a larger proportion

will not do so well,) first put the different ingredients together,

then work th m about with your hands, till you think they are pretty

well incorporated: after which, put them into a lawn sieve with a

receiver and top to it; and if, after it is sifted, any should remain

that will not pass through the sieve, grind it again till fine enough;

and if it be twice sifted it will not be amiss; but the compositions

for wheels and common works are not so material, nor need be so fine.

But in all fixed works, from which the fire is to play regular, the

ingredients must be very fine, and great care taken in mixing them

well together: and observe, that, in all compositions wherein are

steel or iron filings, the hands must not touch; nor will any works

which have iron or steel in their charge, keep long in damp weather,

without being properly prepared, according to the following

directions:--



It may sometimes happen, that fire-works may be required to be kept a

long time, or sent abroad; neither of which could be done with

brilliant fires, if made with filings unprepared; for this reason,

that the saltpetre being of a damp nature, it causes the iron to rust,

the natural 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 should happen to wheels, the fire will not

be strong enough to force them round; to prevent such accidents,

prepare your filings after the following manner:--Melt in a glazed

earthen pan some brimstone over a slow fire, and when melted, throw in

some filings, which keep stirring about till they are covered with

brimstone; this you must do while it is on the fire; then take it off,

and stir it very quick till cold, when you must roll it on a board

with a wooden roller, till you have broken it as fine as corn powder;

after which, sift from it as much of the brimstone as you can. There

is another method of preparing filings, so as to keep two or three

months in winter; this may be done by rubbing them between the

strongest sort of brown paper, which has been previously moistened

with linseed oil.



N.B. If the brimstone should take fire, you may put it out, by

covering the pan close at top. It is not of much consequence what

quantity of brimstone you use, provided there is enough to give each

grain of iron a coat; but as much as will cover the bottom of a pan of

about one foot diameter, will do for five or six pounds of filings.

Cast-iron for gerbes will be preserved by the above method.