ARTIFICIAL FIRE-WORKS. 37 Another Fire Tube. THE circumference of a cylinder is, by a cord, divided into .! certain number of equal parts, and being brought into a poligonal figure, cutting away the convex part, it is brought into angles. Bore the plain sides with a number of holes, perpendi- cularly, so as to penetrate obliquely to the great boring in the middle: into these holes thrust crackers, squibs, or serpents.—See fig. ^8. Fig. 49, exhibits a tube, whose length is six diameters of its thickness. The cylinder being divided round the rim into six parts, and each of those into seven parts, re- serve one of them for the list, between each of which make channels, which being six in number, place little mortars of the same dimensions therein. The mortars must be turned of wood; bore the bot- toms, and add a chamber to them; each chamber must be one-third, or one-half, of the depth of the fluting; and the breadth, one-sixth only. These chambers are de- signed to hold corn-powder. Secure the mortars on the outside with strong paper cases, and nail them fast in the hollow chtmnels, whose cavity they are to fit exactly; their length may be double to their breadth:—each mortar must contain a globe made of paper, with a wooden bottom; and their chambers must be charged with corn-powder. These mortars fix in a spiral line, one only in each flut- ing, with iron stays, and bind the middle with an iron plate, fastened on each side of the interstices; but before you fix the mortars, you must not forget to pierce little holes in the tube, and to fix the touch-holes of your mor- tars exactly upon them, priming both with mealcd-powder. Every thing relating to this may be plainly conceived in the