Mortars used for throwing aigrettes are generally made of paste-board, of the same thickness as ballóón mortars, and two diameters and a half long in the inside from the top of the foot; the foot must be made of elm without a chamber, but flat at top, and in the same proportion as those for ballóón mortars; these sort of mortars must also be bound round with cord as before mentioned; sometimes eight or nine of these sort of mortars, of about three or four inches diameter, are bound all together so as to appear but one; but when they are made for this purpose, the bottom of the foot must be of the same diameter as the mortars; and only half a diameter high. Your mortars being bound well together, fix them on a heavy solid block of wood: to load these mortars, first put on the inside bottom of each, a piece of paper, and on it spread one ounce and a half of meal and corn powder mixed; then tie your serpents up in parcels with quick-match, and put them in the mortar with their mouths downwards; but take care that the parcels do not sit too tight in the mortars, and that all the serpents have been well primed with powder, wetted with spirit of wine; on the top of the serpents in each mortar lay some paper or tow; then carry a leader from one mortar to the other all round, and then from all the outside mortars into that in the middle; these leaders must be put between the cases, and the sides of the mortar down to the powder at bottom: in the center of the middle mortar, fix a fire-pump or brilliant fountain, which must be open at bottom, and long enough to project out of the mouth of the mortar; then paste paper on the tops of all the mortars. Mortars thus prepared are called a nest of serpents, as represented by Fig. 31. When you would fire these mortars, light the fire-pump C, which when consumed will communicate to all the mortars at once, by means of the leaders. For mortars of six, eight, or ten inches diameter, the serpents should be made in one and two ounce cases, six or seven inches long, and fired by a leader, brought out of the mouth of the mortar, and turned down the outside, and the end of it covered with paper, to prevent the sparks of the other works from setting it on fire. For a six inch mortar, let the quantity of powder for firing be two ounces; for an eight inch, two ounces and three quarters; and for a ten inch, three ounces and three quarters; care must be taken in these as well as small mortars, not to put the serpents in too tight, for fear of bursting the mortars. These sort of mortars may be loaded with stars, crackers, &c.