Page:Encyclopædia Britannica, Ninth Edition, v. 18.djvu/242

 224 P A P E R respects similar to those in the revolving cutter, the paper is carried over the measuring drum C, which, by a crank arrangement DE receives an oscillating motion and can be adjusted to draw the exact quantity of paper forward for the length of sheet required. The paper is kept fast on the drum by the gripper rolls F, F, arranged so as to rise and fall FIG. 9. Single-Sheet Paper Cutter. as the drum oscillates, while the dancing roll B keeps the web at a uniform tension. The paper is cut into sheets by the knife I, connected with cranks and links G, and supported by the link rods H, H working horizontally with a swinging motion against the dead knife K. At the same time the clamp L holds the web in position. The sheet to be cut may be seen hanging down at the dotted line M. The sheets are then caught by girls and dressed up in the usual way. This cutter requires a great deal of attention, and is only used when extreme accuracy is required. Calenders. If it is desired to give the paper a higher gloss than can be done on the calenders of the paper machine, or where, as in the case of papers sized with gelatin, these must be glazed- after leaving the paper machine, it Is done by the use either of the plate or roll FIG. 10. Plate Calender. calender. (1) The plate calender (fig. 10) is composed of a framework A, in which are set two highly polished rolls of solid iron B, B, with a space of about f inch intervening. By means of levers and weights pressure can be applied to | the top roll. The paper to be glazed is placed sheet by sheet between copper or zinc plates, till a bundle consider ably thicker than the space between the rolls is made. I This bundle is then passed backward and forward between the rollers, under considerable pressure, and the polished surface of the plates communicates a gloss to the paper. (2) In America a calender of different construction is employed (fig. 11). In it a perpendicular series of highly- polished iron and compressed cotton or paper rolls are placed alternately between frames, and revolve at a high speed. The sheets of paper are one by one introduced by an attendant, who sits in a convenient position near the JL, FIG. 11. Sheet Glazing Calender. top of the calender, under the tapes a, which, running against the roll A, convey the sheet to the next roll B. After passing under the roll A, the paper has a tendency to adhere to the metal surface; this is overcome by a sharp-pointed knife b placed against it, so that the sheet is again caught by the next set of tapes, and so on till it completes its course, and comes out at the foot of the calender. If a still higher glaze is required, the .sheets are passed through a second time. A much larger quantity of paper can be glazed in the same time by one of these calenders than by the so-called plate calender, and at a greatly smaller outlay for wages, but the surface acquired by the paper wants the peculiar gloss communicated to it by the latter, and for the higher grades of paper this still retains its position in Great Britain. After being cut, and, if necessary, calendered, the paper is sorted, that is to say, it is examined sheet by sheet, and all torn or soiled sheets are taken out. It is then counted into quires and reams, each quire containing twenty-four sheets, and each ream twenty quires. Hand-Made Paper. So far the preparation of pulp, whether for paper making by hand or by machine, is iden tical, the chief difference being that only the most expensive drawing and writing papers are now manufactured by hand, and for this purpose only the finest qualities of rags are used. The process will be best understood by reference to the drawing (fig. 12). The pulp, after being prepared in the beating engine as above described, is run into large chests from which the vat is supplied. Before reaching this it is strained as on the paper machine. Hand-made paper is made by means of a mould (tig. 13). This consists of a framework of fine wirecloth with a &quot; deckle &quot; or movable frame of wood all round it, to keep the pulp from running off. Nearly all &quot;hand-made papers have also a water-mark (W. King in this instance), which is produced by wires representing these letters being raised above the rest of the mould. Hence the paper in these parts is thinner, and the letters can be read on holding the sheet up to the light.