Common port fires are intended purposely to fire the works, their fire being very slow, and the heat of the flame so intense, that, if applyed to rockets, leaders, &c., it will fire them immediately. Port fires may be made of any length, but are seldom made more than twenty one inches in length; the interior diameter of port fire moulds, should be ten sixteenths of an inch, and the diameter of the former, half an inch. The cases must be rolled wet with paste, and one end of them pinched, or folded down. The moulds should be made of brass, and to take in two pieces lengthwise; then when the case is in the two sides, they are held together by brass rings, or hoops, which are made to fit over the outside. The bore of the mould must not be made quite through, so that there will be no occasion for a foot. Those port fires when used, are held in copper sockets, fixed on the end of a long stick; these sockets are made like port crayons, only with a screw, instead of a ring. Of Cascades of Fire. Cascades are made of any size, but one made according to the dimensions of that shewn in plate 4. fig. 43. will be large enough for eight ounce cases. Let the distance from A to B, be three feet; from B to C, two feet six inches; and from C D, two feet; and let the cross piece, at A, be four feet in length; then from each end of this piece, draw a line to D; then make the other cross pieces of such a length as to come within those lines. The top piece D, may be of any length so as to hold the cases, at a little distance from one another, all the cross pieces are fixed horizontally, and supported by brackets; the bottom cross piece should be about one foot six inches broad in the middle, the second one foot, the third nine inches, and the top piece four inches; the cases may be made of any length, but must be filled with a brilliant charge; on the edges of the cross pieces must be nailed bits of wood, with a groove cut in each piece, large enough, for a case to lie in, These bits of wood are fixed so as to incline downwards, and that the fire from one teer of cases may play over the other; all the cases being tied fast on, carry leaders from one to the other, and let there be a pipe, hang from the mouth of one of the cases, covered at the end with a single paper, which you burn to fire the cascade. Of the Fire-Tree.