PRIME figure, in geometry, one which cannot be divided into any other figures more simple than itself, as a triangle among planes, and the pyramid among solids.
brings the screw and the swinging bed of the press down upon the bag, and com presses it into a very small space. A small cord is now passed through the spaces be tween the pieces of wood, forming the lower side of the swinging bed, and the tipper side of the fixed bed, and reefed twice round the bag, and tied fast : the man at the handles now turns it back, and draws up the swinging bed to relieve the bag, the cord retaining it in its compress od state.
In 1798, the Society for the Encourage ment of Arts, Manufactures, and Com merce, rewarded Mr. John Peak, of the New Road, near the Adam and Eve, Lon don, with thirty guineas, for an improved packing press, shown in fig. 3, Plate Press, which is a front elevation of the machine, A A, the frame of the press ; B B, the large screws, which, in this press, contrary to those in common use, are fix ed and immoveable; C, a circular iron bar, extending beyond the sides of the press, and having thereon two worms or endless screws, E, E, which work it two toothed wheels, fixed to the nuts ; by turning the winch, 1), the nuts and bed are driven up and down the screws, as may be found necessary. F, a stage suspended from
the bed, and on which the men stand who work the press ; such a stage may, if found necessary, be fixed at the other end of the bar, another winch being put upon the square shoulder, G. The bed of this press must be formed of two pieces of strong wood, which are held together by screws and nuts passed through them, as shown at 71 h h h.
One very considerable advantage of this press is, that much time is saved by its being a double press ; for it will very readily be perceived, that when the low er package has been sufficiently pressed, as the bed or presser is raised, (another package being thereon) the upper pack age begins to be pressed, as that one un derneath is relieved, and so alternately, during the whole operation.