The "wire" is an endless cloth made of very fine wire, the fineness depending much on the quality of the paper required. The mesh varies from 60 to 70 and even more threads to the inch. It is not woven endless, but is joined by very careful sewing, with wire. Its width varies consider ably, that on the machine shown being 76 in.; the length is generally 35-40 ft. It is carried by the breast-roll F (Figs. 1051 and 1052), the lower couch-roll G, end the small rolls! (Figs. 1052 and 1053), and by a large number of small rolls f'. The latter and the breast-roll are supported by the frame g, while the small rolls f are supported by brackets attached to it. The course of the wire is indicated by the arrows. The frame g works on two pivots g' (Fig. 1053), and receives a shaking motion from side to side from the rod j (Fig. 1051), in connection with a crank worked by two conical drums H (Fig. 1051). The supports g" are also pivoted at their lower ends to allow for the shaking motion. This shaking motion is given for the purpose of weaving or intertwining the fibres. One or more of the rolls f' can be moved up or down on the support which carries it, for the purpose of stretching the wire. There is usually a large number of the small rolls f", ae it has been found by experience that, probably owing to capillary attraction, they assist the water to leave the pulp. Though a large quantity of water thus passes through the wire-cloth, it is necessary to assist it by artificial means. This is done by means of the suction-boxes I (Figs. 1052 and 1051) connected by pipes with the vacuum-pumps I' (Fig. 1053).
Underneath the wire-cloth, is placed a box called the "save-all' K (Fig. 1052), connected with the box E (Fig. 1051). The water that flows in here contains a considerable quantity of very fine fibres, together with size, alum, clay, and colouring materials, that have passed through the wire, and which would be lost but for the arrangement now universally adopted. It flows into the box E', and is pumped, together with the pulp that has pissed through the knotter E (see before) into the high box B, whence the mixed stuff flows on the sand-tables, to be again used to dilute fresh pulp from the stuff-chests. If any pattern or name is desired on the paper, it is done by means of a light skeleton roll, called a "dandy-roll," covered with wires in the form of the desired pattern, placed between the suction-boxes, and pressing lightly on the still moist paper. The paper is thinned where the wire pattern presses, and thus a mark (water-mark) is produced. The other side of the paper has a mark corresponding to the wire-cloth ; by using u dandy-roll covered with wire-cloth, the two sides can be obtained alike, such paper going by the name of " wove." It sometimes happens that the wire-cloth slips slightly to one side. This can be obviated by
the machine-man shifting, by means of screws, one of the rolls provided for the purpose with a movable journal, until its axis is at a slight angle to that of the other rolls. An automatic apparatus has been invented for the purpose. Two brass plates are fixed, one on each side of the wire-cloth, to a long rod, connected by suitable machinery with the screws working the movable journal, so that, as the wire presses against one or the other of these plates, the roll is shifted so as to correct this.
The paper, which, even after peeing the suction-boxes, is still very wet, passes with the wire cloth between the couch-rolls G G'. (Figs. 1053 and 1051). These are hollow copper or brass cylinders, covered with a tightly-fitting endless jacket of felt. The pressure of the upper couch-roll upon the lower can be regulated by means of screws or levers. They serve to press out water from the paper, and to detach the paper from the wire-cloth. By dextrous manipulation on the part of the machine-men, the paper is transferred to the endless felt, travelling over the rolls k in the direction of the arrows. It is known as the " wet felt," from the condition of the paper at this stage. In its passage along this felt, the paper goes between two iron rolls K, called the first press-rolls, with the object of having the water squeezed or pressed out of it. These rolls are sometimes covered with a thin brass case, and the top one is provided with an arrangement called the " doctor,' in order to keep it clean, and free from pieces of paper that may have stuck to it. The " doctor " is a kind of knife placed along the whole length of the roll, and pressing against it at every point.
The pressure on the rolls can be regulated by means of levers, or, as in the illustration, by the screw h' (Fig. 1054). It will be readily seen that the under side of the paper that has been next to the felt will, in its still moist condition, have taken to some extent an impression from the felt, while the upper side will have been made comparatively smooth by the pressure against the top roll of the let press. In order to make both sides of the paper as nearly as possible alike, it is passed through another set of rolls L, called the 2nd press. This time it is reversed, and enters at the back of the rolls ; thus the other side of the paper is next the metal, being taken through by the felt (called the " 2nd press felt ") travelling on the small rolls / (Fig. 1054), the paper, after leaving the wet felt, and before being taken on to the 2nd press felt, travels over the rolls /'. The 2nd press felt is necessary, because the paper in its then condition is too tender to withstand unsupported the pressure of the rolls.