From the stuff-chest the mixture is pumped into what is known as the “mixing” or “regulating” box.  Here the stream first passes over the “sand-tables” in a continuous flow.  These are composed of little troughs with cross-pieces, and are covered at the bottom with long-haired felt, to catch any sand or dirt that may still adhere after the numerous operations to which the pulp has been subjected.  The flow is then forced through the “screen,” which is a horizontal piece of metal pierced with slots.  For very fine paper these slots are so small as to be only one one-hundredth of an inch in width.  They are usually about a quarter of an inch apart.  Through these tiny apertures the fibers must find their way, leaving behind in their difficult passage all lumps, dirt, or knotted fibers which would mar the perfection of the product toward which they are tending.  A vibrating motion is given to the screen as the flow passes over it, or revolving strainers may be used.

When the screen has finished its work, the water carrying the pulp in solution flows in an even stream, the volume of which varies according to the width of the web of paper to be produced, through a discharge-cock onto the Fourdrinier or cylinder machine, as the case may be, each of which will be duly described.  This stream has a filmy appearance and is of diverse color, depending upon the shade of paper to be produced.  From its consistency, which is about that of milk, it is difficult to imagine that it floats separate particles of fiber in such quantities as, when gathered on the wire cloth and passed to a felt blanket and then pressed between rollers, to form in a second of time a broad web of embryo paper sufficiently strong and firm to take definite form.  Man’s mastery of the process by which this startling and wonderful change is effected has come as one of the rewards of his long and patient study.

The Fourdrinier machine, which preserves at least the name of the enterprising developers of the invention, takes up the work that was formerly done by the molder.  The wire cloth upon which the fibers are discharged is an endless belt, the full width of the paper machine.  Upon this the fibers spread out evenly, being aided by a fan-shaped rubber or oil cloth, which delivers the smooth stream under a gate regulated to insure perfect evenness and to fix uniformly the fibers of the web now commencing its final formation.  Deckel-straps of india-rubber are fastened on both sides of the wire screen, and move with it, thus holding the watery pulp in place.  The deckel-straps are adjustable and fix or regulate the width of the paper.  These and the gate, or “slicer,” are attached to what is termed the deckel-frame, which corresponds to the deckel used by paper-makers in the days when the manufacture was carried on by hand.  As the stream flows onto the endless belt of wire cloth, the water which has borne the fibers filters into the trough beneath.  Being charged with very fine