hulling- or decorticating-machine shown in our illustrations 3, 4) consists of a cylindrical casing in which is a series of cast-iron discs fixed on a vertical spindle, which in running makes about three hundred and fifty revolutions per minute. Radially, and at right angles to their planes, the peripheries of these discs are set with thin steel blades from 12 to 16 per inch, which are separated by pasteboaed interpacking of a less width and length, so that the edges of the blades project. The casing has open wire-work (D, D ;Jig. 4) on its two opposite sides, and the two intervening portions are lined with steel blades (C, C) similar to those on the discs, with a space of from =;6 to an inch between the ends of the blades of the discs and those of the casing. Between each of the revolving discs, and close to their circle of blades, is a fixed annular disc (E) furnished on its opposite sides with a similar arrangement of blades, thus dividing the machine into a series of horizon tal compartments. At intervals in the fixed annular discs holes are made, which can be closed to any required extent by slides (I, I).
The grain, which is fed through a pipe (C; pi. 4, fig. 3) in the cover of the casing, passes clown between the edges of the blades (/)) on the first revolving disc and the fixed blades (C, If) on the casing, and thence down through the successive compartments to the bottom of the machine. A por tion of the epidermis of the grain is removed by the action of each revolving disc, and the particles thus cut off, aided by a current of air, escape through the wire-work portions of the casing. The regulating-slides (/, I; fig-. 4) of the annular discs afford the means of retaining the grain a longer or shorter time under the action of the blades in each compartment, and india-rub ber brushes arc inserted at J1,11, for pressing the grain close to the revolv ing discs. The cleaned grain is delivered into the spouts (J, J; fig. 3) at the bottom of the machine. About seven per cent. of the whole grain is removed by this process. The portion removed is a dark, soft, and greasy substance whose presence is deleterious to the flour, but it has a commercial value, as food for cattle, equal to that of bran. The machine while in motion renews its cutting-edges: as the sharpness of the front cutting-edges of the blades is worn off a new edge is set up on the oppo site sick of the blades; so that it is only necessary to reverse the motion of the discs to maintain a constant and efficient action of the machine.
Ei-ans's Jfill.—Toward the close of the last and early in the pres ent century, Oliver Evans invented and put in operation many mechanical devices which are entitled to be called " scientific." He gave the first impetus to the art of milling- in America, and his patented improvements in milling-mechanics were finally combined into one complete system. His inventions for converting grain into flour embraced the elevator, the con veyer, the hopper-boy, thedrill, and the descender, "which five machines" —quoting from his Young Millzoricla—" are variously applied in differ ent mills, according to their construction, so as to perform every necessary 1110VellIellt of the grain and meal from one part of the mill to another or from one machine to another, through all the various operations, from the time the grain is emptied front the wagoner's bag or from the measure on board the ship until it is completely manufactured into superfine flour and other different qualities, and completely separated ready for packing into barrels for sale or exportation; all of which is performed by the force of water, without the aid of manual labor except to set the different machines in motion."
Evans's system of milling is illustrated in Figure r4, which exhibits the operation of his labor-saving machines. The following explana tion of the Figure is condensed from his description: The grain from the wagon is delivered into a spout (1), which directs it to the scale (2). When weighed, the grain is drawn into the garner (3), at the bottom of which is a gate, that admits it to the elevator (4, 5), which raises and delivers it into the great store-garner (6), whence it descends through suitable connecting passages into the garner (7), over the mill-stones (S), where the grain is rubbed before grinding. As rapidly as the process of rubbing is completed the grain again runs (as indicated by the dotted lines) into garner 3; in its passage thence it goes through an air-current blowing into an air-tight chamber (9), which contains a spout (a), extend ing through the floor for the escape of the air, which carries out with it (at a) most of the dust. The grain then again flows into the elevator (at 4) and is raised to 5, whereupon, the crane-spout being turned, the grain is deposited in the screen-hoppers (to, II). From these hoppers it runs into the roller-screen (r2) and descends (r4) through a current of air generated by the fan (13) into the conveyer (15, 16), which conveys it to all the garners (7, 17, 18) that supply the millstones (S, 19, 20). The meal falls from the stones to the conveyer (21, 22), which carries it to the flour-elevator (23) and raises it to 24, whence it gently runs down the spout to the hopper-boy (25), which spreads and cools the flour and gathers it into the bolting-hoppers. As it passes through the first reel (26) the superfine flour falls into the packing-chest (28); the tailings, which require rebolting as they come from the first and second reels (26, 27), are guided by a spout (dotted lines 31, 22) into the conveyer (22, 23), to be hoisted again for further treatment. The middlings are conveyed into the eye of either pair of millstones by the conveyer (31, 32) and reground with the wheat. The light grains, screenings, etc., blown out by the fan (13) fall into the screenings-garner (32); the chaff, being driven farther on, settles in the chaff-room (33), while the greater part of the dust is carried out by the air through an aperture in the wall. To the left, in the Figure, is seen the system of elevating grain from a water-transport. It is raised to the top story of the mill, whence its course is essentially the same as that above described.