All compositions for fire-works, are generally made at first in mortars, and the mixture is then finished by passing it through a sieve; it being returned to the sieve, and again sifted. This operation is sometimes repeated several times. Of all compositions, that for sky-rockets requires to be most intimately blended.
To receive the sifted matter, leather or parchment is used; but, in lieu of either, pasteboard, or several sheets of paper, cemented or glued together will answer. It is obvious, that, in preparing mixtures, of two, three, or four articles, they should not only be very fine, but uniformly and intimately mixed.
Several receivers, made by stitching leather over a rim, in the manner of a sieve, would be found very convenient; but wooden bowls, and copper basins, are generally used.
Some ingredients must be passed through a lawn sieve, after having been previously incorporated. A receiver, with a top, is the kind of sieve to be preferred. The composition for wheels, and common works, need not be so fine as for rockets. But in all fixed works, from which the fire is to play regularly, the ingredients must be very fine, and great care taken in mixing them together; and in those works, into the composition of which, iron and steel enter, the hands must neither touch them, nor moisture be suffered to come in contact. In either case, they would be apt to rust.
[PART III.]
FIRE-WORKS IN GENERAL.