Meal-powder,2 lbs.4 oz.
Charcoal,—4½ —

For eight-ounce tourbillons.

Meal powder,2lbs.
Charcoal,4¾oz.

For large tourbillons.

Meal-powder,2lbs.
Saltpetre,1do.
Sulphur,8oz.
Beat-iron,8oz.

As a general rule, we may remark, that the larger tourbillons are made, employing, if necessary, different coloured fires, the weaker must be the charge; and, on the contrary, the smaller, the stronger their charge.

Sec. VI. Of Mortars for throwing Aigrettes, and the manner of loading and firing them.

Pots of aigrette, when inflamed, exhibit the appearance of an aigrette, or cluster of rays, such as are produced by diamonds, when they are arranged in a particular way. The aigrette takes its name from a bird, whose feathers serve to make up an ornament for the head. It was given in diamonds, as a particular mark of distinction, by the Grand Signior, to Lord Nelson, after the battle of the Nile. There are aigrettes made of glass.

For the purpose of throwing aigrettes, the mortars are generally made of pasteboard, of the same thickness as balloon mortars, and two and a half diameters long in the inside from the top of the foot. The latter must be made of elm without a chamber, but flat at top, in the same proportion as those for balloon mortars. These mortars must be bound round with a cord as before mentioned. Sometimes eight or nine of these mortars, of about three or four inches in diameter, are bound altogether, so as to appear as one; but when they are prepared for this purpose, the bottom of the foot must be of the same diameter as the mortars, and only one-half a diameter high. Having bound the mortars together, fix them on a heavy solid block of wood. To load them, place over the inside bottom of each, a piece of paper, and spread on it one and a half ounces of meal and grain powder mixed; then tie the serpents up in parcels with quickmatch, and put them in with their mouths downwards. Care must be taken, that the parcels do not fit too tight in the mortars, and that all the serpents have been well primed, or wetted with the paste of meal powder and spirit of wine.