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a plan of the horizontal mill erected at Margate by captain Hoopers H H are the side walls of an octagonal building which contains the machinery, These walls are surmounted by a strong timber-framing G G, of the same form as the building, and connected at top by cross-framing to support the roof, and also the upper pivot of the main vertical shaft A A, which has three sets of arms, B B, C C, and D D, framed upon it at that part which rises above the height of the walls. The arms are strengthened and supported by diagonal braces, and their extremities are bolted to octagonal wooden frames, round which the vanes or floats E E are fixed, as seen in outline in fig. 2, so as to form a large wheel resembling a water-wheel, which is lef* than the size of the house by about eighteen inches all round. This space is occupied by a number of vertical boards or blinds F F, turning on pivots at top and bottom, and placed oblique, so as to overlap each other, and completely shut out the wind, and stop the mill, by forming a close case surrounding the wheel; but they can be moved all together upon their pivots to allow the wind to blow in the direction of a tangent upon the vanes on one side of the wheel, at the time the other side is completely shaded or defended by the boarding. The position of the blinds is clearly shewn at F F fig. 3. At the lower end of the vertical shaft A A, a large spur-wheel a a is fixed, which gives motion to a pinion r, upon a small vertical axis d, whose upper pivot turns in a bearing bolted to a girder of the floor N. Above the pinion c, a spur-wheel / is placed, to give motion to two small pinions /, on the upper ends of the spindles g of the mill-stones k. Another pinion is situated, at the opposite side of the great spur-wheel a a, to give motion to a third pair of mill-stones, which are used when the wind is very strong ; and then the wheel turns so quick, as not to need the extra wheel e to give the requisite velocity to the stones. The weight of the main vertical shaft is borne by a strong timber b (?), having a brass box placed on it to receive the lower pivot of the shaft It is supported at its ends by cross-beams mortised into the upright posts b b, as shewn in the plan, fig. 2. A floor, or roof, I I, is thrown across the top of the brick building, to protect the machinery from the weather ; and to prevent the rain blowing down the opening through which the shaft descends, a broad circular hoop K is fixed to the floor another hoop or case L, which is fixed to the arms D D of the wheel, This shaft is of such a sizet as exactly to go over the hoop K, without touching it when the wheel turns round. By this means, the rain is completely excluded from the upper room M, which serves as a granary, being fitted up with bins m m, to contain the different sorts of grain which is raised up by the sack-tackle. A wheel t is fixed on the main shaft, having cogs projecting from both sides. Those at the underside work into a pinion on the end of the roller J, which is for the purpose of drawing up sacks* Another pinion is situated above the wheel which has a roller projecting out over the flap-door as seen at p, in the fig, 2, to land the sacks upon. The two pinions mm fig. 2 are turned by the great wheel 10, and are for giving motion to the dressing and bolting machines, which are placed upon the floor N, but are not shewn in the drawing, being exactly similar to the dressing-machines used in all flour-mills. The cogs upon the great wheel a are not so broad as the rim itself, leaving a plain rim about three inches broad. This is encompassed by a broad iron hoop, which is made fast at one end to the upright post b ; the other being jointed to a strong lever n , to the extreme end of which a purchase 0 is attached, and the fall is made fast to iron pins on the top of a frame fixed to the ground. This apparatus answers the purpose of the brake or gripe used in common wind-mills to stop their motion. By pulling the fall of the purchase o, it causes the iron strap to embrace the great wheel, and produce a resistance sufficient to stop the wheel. The mill can be regulated in its motion, or stopped entirely, by opening or shutting the blinds F, which surround the fan-wheel. They are all moved at once by a circular ring of wood situated just beneath the lower ends of the blinds upon the floor I 1, being connected with each blind by a short iron link. The ring is moved round by a rack and spindle, which descend into the mill- room below, for the convenience of the miller.