Plate 2, Fig. 18, represents the plan of an apparatus, or lath, for boring of rockets; A the large wheel which turns the small one B, that works the reammer C: these reammers are of different sizes according to the rockets; they must be of the same diameter as the top of the bore intended, and continue that thickness a little longer than the depth of the bore required, and their points must be like that of an auger; the thick end of each reammer must be made square and all of the same size, so as to fit into one socket, wherein they are fastened by a screw D: E the guide for the reammer, which is made to move backwards and forwards; so that after you have marked the reammer three diameters and a half of the rocket from the point, set the guide, allowing for the thickness of the fronts of the rocket boxes, and the neck and mouth of the rocket, so that when the front of the large box is close to the guide, the reammer may not go too far up the charge; F, boxes for holding the rockets, which are made so as to fit one in another; their sides must be equal in thickness to the difference of the diameters of the rockets, and their interior diameters equal to the exterior diameters of the rockets. To prevent the rockets turning round while boring, a piece of wood must be placed against the end of the box in the inside, and pressed against the tail of the rocket; this will also hinder the reammer from forcing the rocket backwards. G, a rocket in the box. H, a box that hides under the rocket boxes to receive the borings from the rockets, which falls through holes made on purpose in the boxes; these holes must be just under the mouth of the rocket, one in each box, and all to correspond with each other. Fig. 19, is a front view of the large rocket box. I, an iron plate, in which are holes of different sizes, through which the reammer passes; this plate is fastened with a screw in the center, so that when you change the reammer, you turn the plate round, but always let the hole you are going to use be at the bottom; the fronts of the other boxes must have holes in them to correspond with them in the plate. K, the lower part of the large box, which is made to fit the inside of the lathe, in order that all the boxes may move quite steady. Fig. 20, is a perspective view of the lathe. L, the guide for the reammer, which is set by the screw at bottom.