Fig. 24, represents a wooden former; 25, a gerbe compleat, with its foot or stand. The cases for gerbes are made very strong, on account of the strength of the composition; which, when fired, comes out with great velocity; therefore, to prevent their bursting, the paper should be pasted, and the cases made as thick at the top as at the bottom; they ought also to have very long necks, for this reason; first, that the particles of iron will have more time to be heated, by meeting with greater resistance in getting out, than with a short neck, which would be burnt too wide before the charge be consumed, and spoil the effect: Secondly, that with long necks the stars will be thrown to a great height, and will not fall before they are spent, or spread too much; but, when made to perfection, will rise and spread in such a manner as to form exactly a wheat-sheaf. In the ramming of gerbes, there will be no need of a mould, the cases being sufficiently strong to support themselves; but you are to be careful, before you begin to ram, to have a piece of wood made to fit in the neck; for if this be not done, the composition will fall into the neck, and leave a vacancy in the case, which, as I said before, will cause the case to burst as soon as the fire arrives at the vacancy: you must likewise observe, that the first ladle of charge, or two, if you think proper, be of some weak composition. When the case is filled, take out the piece of wood, and fill the neck with some slow charge. Gerbes are generally made about six diameters long, from the bottom to the top of the neck; their bore must be one fifth narrower at top than at bottom. The neck S is one sixth diameter and three fourths long. T, a wooden foot or stand, on which the gerbe is fixed. This may be made with a choak or cylinder, four or five inches long, to fit the inside of the case, or with a hole in it to put in the gerbe; both these methods will answer the same. Gerbes produce a most brilliant fire, and are very when a number of them are fixed in the front of a building, or a collection of fireworks. N. B. Gerbes are made by their diameters, and their cases at bottom one fourth thick. The method of finding the interior diameter of a gerbe is thus: Supposing you would have the exterior diameter of the case, when made, to be five inches, then, by taking two fourths for the sides of the case, there will remain two inches and a half for the bore, which will be a very good size. These sort of gerbes ought to be rammed very hard. Of small Gerbes or White Fountains.