But it will not be amiss to mention, though at the hazard of some repetition, the precautions and cares which these very important fireworks demand ; whether made simply of a light only, or whether provided with crackers or reports at their termination.
A considerable number of compositions are given in our table of compositions, whence the artist may se lect different colours, so as to vary the effects, all of which must depend on his own taste, and on the na ture of his projected design. It is extremely neces sary, as we formerly remarked, that all these composi tions, of whales er nature they may be, should be very fitudy powdered and intimately mixed ; as their cor rect performance depends in a great measure on this, and that all those which are to burn together should be filled from the same lot of composition, and by the same hand.
The cases for these must vary in size, according to the magnitude of the firework into which they are to enter, and the distance at which it is to be viewed. A length of three inches, by a diameter of half an inch, interiorly, is as small as they can well be requir ed for making figured illuminations, such as those now under review ; and from that they may be extended to double the dimensions and upwards. These cases must all be driven in moulds, without which it would be impossible to give them the requisite uniformity ; and this is done with the bottom downwards, as they are not choked for burning. If they are to be pro vided with crackers or bounces at the end, that nmst be managed in the manner not long ago directed for saucissons; but the cases for this purpose must be half as long again; and that part which contains the bounce may also be fortified with some additional turns of paper, and of packthread, if the artist thinks fit.
To make these illumination lights ready for firing, they must be nailed firmly down to the frames, by means of proper fiat-headed nails, fitted to this pur pose; or else they may be secured in sockets of tin, fitted to the frame-work, or to iron hooks, by means of packthread. When thus disposed in their proper or der, the leader is to be attached to the whole, in one continuous line, taking care that every light has a fair communication with it; and it must be secured at each joint by means of pasted paper, to prevent the hazard of any accidental spark firing the lights before their time. This, however, must neither be so thick,
nor so firmly fixed, but that it may blow off and dis engage itself as the case fires ; lest, in so doing, it should disturb any of the lights to which it was attached. If there is a great or long range of these to be fired at once, it is better not to trust to one place of firing, on account, of the time taken for the fire to communicate through a very long leader. Two or three points, at equal distances, should be selected in the line of cons munication, and a leader being attached to each of these, they must all be collected together, into one common point fur firing. Thus the fire will be more equally distributed, and the whole range, howe% er lung it may be, will be lighted together. This pre caution is particularly necessary where it is a large building that is to be illuminated; and, unless it is at tended to, one part will go out while the rest is continu ing to burn ; a circumstance which always produces a very disagreeable effect.
We shall here subjoin the compositions which we consider the best for the larger lights, referring to our table of compositions for those which are in use among the pyrotechnists.
This is used for large signal lights, being inclosed in wooden tubes or pots, or in paper cases, or in iron pots. varying from one to six inches in diameter, and from four inches to a foot in depth. The illumination is very powerful.
The same composition being driven as hard as pos sible into a globe of strong and thick pasted paper, sufficient to bear the explosion of a mortar, is thrown into the enemies' works at night to discover what they are doing. The ball or paper carcass should have three holes, of an inch and half diameter, each furnish ed with a quick match and priming of powder, well secured by a pasted paper cover.