The next process is granulation, or reducing this press cake into the proper sized grain for cannon, musket, or rifle powder. The machine which effects this is very beautifully contrived, and is entirely self-acting, obviating the necessity of any one being in the building while it is in motion. It resembles, in appearance and action, the breaking-down machine, except that it is larger, and is fitted with three pairs of toothed rollers, of different degrees of fineness, working in the same kind of collars already mentioned, so that, on any hard substance passing through, they would open accordingly, and thus prevent friction. At one end of the machine is a wooden hopper, or funnel, which is filled with the press cake. This is contrived so as to rise gradually by the motion of the machine, and constantly to supply an endless band, similar to the one described in the breaking-down house. When the cake arrives at the highest point of this band, it falls over, and is granulated between the first pair of gun-metal rollers. Under each pair is a screen, covered with 8-mesh wire. All that is not sufficiently small to pass through, is carried on to the next pair of rollers; and, in like manner, that which does not pass through the second screen is carried to the third pair. In addition to these screens, there are three oblong sieves covered with 8- and 16-mesh wire, and 56 cloth respectively, fixed under, and parallel to, each other, each being separated by about four inches of space, running at an incline just below the three pairs of rollers; these all lead to little wooden carriages placed on the opposite side of the machine, which are divided so as to collect the different sized grain as it passes down. To facilitate the separation and sifting of the powder, and to prevent masses of it forming and clogging up the wire, a shaking motion is imparted by a circular wheel attached to the framework of these sieves revolving against an octagonal one fixed to the machine. The grains which pass through each screen below the rollers fall on the upper one of these three last-mentioned sieves. That portion which passes through this, and is retained on the 16-mesh wire, is cannon powder; that passing through the 16-mesh sieve, and retained on the 56-cloth, is fine grain; and a board, running also parallel underneath, retains the dust that passes through the cloth. ~Chucks regranulated.~ The “chucks,” as they are called, or those grains that are too large to pass through these different sieves, are collected in the same way as the grain, and undergo the process of granulation again. DUSTING LARGE-GRAIN POWDER. ~Object of dusting.~ ~How performed for large-grain.~ ~Glazed at same time.~