This exhibition, it is obvious, may be varied according to circumstances, either by employing a larger quantity of the composition in several cases, or by using one or more marrons, or some other descriptions of fire-works, the effect of which is calculated to increase the flame, and to produce the necessary variations.
Sec. III. Of the Flames.
If a flame is to be represented, as for example, the effect of an incendiary, and its appearance is to be prolonged, the fire from tow being too transient, small iron kettles, of four inches in diameter, and depth, may be used. In these are put three or four ounces of the composition of the lances of service, which is moistened with the oil or spirit of turpentine. When set on fire, they will produce a blaze three or four feet in height, and one and a half in diameter. Several may be used, according to the effect required. See the composition for the [lances of service.]
Sec. IV. Of the Fire-rain.
A variety of compositions for fire-rain are used, which will be noticed, when we speak of the garnishing of rockets, and other fire-works.
Cases are prepared of seven-twelfths of an inch in diameter, and ten inches long, which are choaked in such a manner, as that the hole of communication should be one-third of the diameter of the interior case. They are then charged with the following composition:
Composition of the fire-rain.
| Saltpetre | 8 | ounces. |
| Sulphur | 4 | do. |
| Meal powder | 16 | ounces. |
| Charcoal of oak | 2½ | do. |
| Pitcoal | 2½ | do. |
When the cases are charged and primed, they are tied upon a rod, having a groove cut in its length. In the inside of the groove, is a port-fire, or leader, which is tied to the cases with twine, and the groove is then covered with several pieces of paper, in the shape of a band.
This precaution is thus taken for the theatre, in order to prevent the inflamed port-fire from falling on the stage.