In it the frame _f_ carrying the deckle-strap is made to slide along the rods _e_ by means of the small wheel _b_, and by a similar arrangement on the opposite side and geared with it. The movable apron _l_, Fig. 49, is wound round the spindle _g_, and is kept taut by the cords _m_ connected with the springs _n_. As the deckles approach each other, the excess of apron is wound up, when they are separated it unwinds again. The flow of pulp is regulated by two slices _a a_, which are kept in position by the screws _h_. The whole arrangement is securely bolted to the frame of the machine; _c_ (Fig. 50) represents the breast-roll, and corresponds to F, Plates I. and II. [Illustration: FIG. 50.] The thickness of the paper is regulated by altering the supply of pulp to the wire-cloth, and by the speed at which the machine is working. This speed may vary from about 60 feet to as high as 270 feet per minute. 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 considerably, some {154} being made as wide as 126 inches; the length is generally 35–40 ft. It is carried by the breast-roll F, the lower couch-roll G, and the small rolls _f′_, 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′_, and receives a shaking motion from side to side from the rod _j_, in connection with a crank worked by two conical drums H. 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″_, as it has been found by experience that, probably owing to capillary attraction, they, cause 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 connected by pipes with the vacuum-pumps I′. This part of the machine, which is called the “wet-end,” is placed at a slight slope of about 1 in. in its entire length, the lowest end being nearest the strainers.