tubes or otherwise; or they may be partly open or partly shut in any intermediate degree, so that the quantity of pulp or paper stuff required to run from the vat upon the under web may by this means be regulated and adjusted to the velocity of the under web, as to produce a sheet of paper of any required thickness. We cause the pulp or paper stuff in the vat to be constantly stirred or agitated as long as the machine continues at work by certain pieces of mechanism commonly used in paper mills for that purpose, and well known to the manufacturers by the appellation of hogs; and these are represented at TTTT. The inclined plane B B, which is affixed to the upper edge of the trough in the front of the vat for the purpose of conducting the pulp from thence to the surface of the under web, is a copper plate hammered exceedingly flat and true, and otherwise reduced to as perfect a plane as possible. The pulp is prevented from spreading itself laterally, or running off sideways from the inclined plane, by proper pieces set edgeways thereon for that purpose. To prevent confusion in the drawing, we have shewn the inclined plane in the section only at B B and its support f, but its situation on the plan is denoted by the dotted lines BBBB. The upper edge of the trough over which the pulp flows upon the inclined plane at g should be exactly level, and about seven or eight inches below the upper edge of the vat, and about five inches above the surface of the under web. The required angle of the inclined plane will vary the quality and quantity of the pulp to be thrown upon the web, and must be ascertained by experiment. As the pulp ought to fall upon the under web with as little velocity as possible, we therefore place a small copper or wooden trough across the surface of the under web, and about half an inch

above it, and supported at each end by the dickles. The situation and figure of this trough (which we call the delivering trough) is shewn in the section at c, and likewise one of the regulating screws U, by which it is raised or lowered as the thickness of the paper may require, by having a screw at each end. By this means the rapidity of the pulp is considerably lessened by falling first into the trough and then upon the web. But it may still be further decreased by causing the flap of oiled silk to extend beyond and underneath the edge of the trough from which the pulp falls upon the silk and from thence runs gently upon the web. VVV is the wooden frame work supporting the various parts of the machinery. J and K the first or wet press cylinders or rollers with the revolving webs a a, &c. and dd, and passing between them, are darts or arrows, denoting the direction in which the webs move. W and X the iron spindles of the cylinders, hh the iron car riages, and bearing brasses ii, in which the spindles of the cylinder are supported and turn, k the compressing screws by which the upper cylinder is forced down upon the under one, to give the necessary pressure to the paper. The upper part of the iron carriages hh is fastened to the under part by screws or otherwise, and may be detached therefrom at any time when it may be necessary to remove the cylinders from their places for the purpose of putting on new webs, &c. L and M are the two rollers upon which the upper web revolves, Y and Y are their supporters, in the upper ends of which are placed the pieces of brass Z and Z*, which slide backward and forward, and in these pieces the pivots or * The rollers L and M, and their supports Y and Y, are only shewn in the section.

VOL. XIII.-SECOND SERIES.

Gg

bearings

bearings of the rollers L and M turn. Therefore by sliding out these pieces and the rollers in a proper direction by means of the screw, the upper web may be properly extended, and the rollers L and M placed exactly parallel with the wet press cylinders J and K. C and E are the two extreme rollers upon which the under web revolves, and by which it is extended. The pivots of the roller E rest upon, and turn in, the upper part of the cast iron carriages mm, which are firmly connected with each other by a cross bar; the ends of the bar, or outside of the carriages, being confined at each side of the machine frame by the iron plates nn, between which the bar, carriages and the roller E may slide backward and forward in a direction perpendicular, or at right angles, with the roller E, for the purpose of tightening or slacking the under web, as a greater or less degree of tension may be required. And we cause the said cross bar, with the roller last mentioned, to be moved backward and forward by two screws applied at each end of the cross bar; and by the application of wheel work thereto, we cause the same to make an equal number of revolutions in the same time; each screw having an equal number of threads in the same quantity of space; so that whenever it is necessary to tighten or slacken the web, the roller E will always move parallel with its first position, and with the press cylinders. The particular application of the screws and wheel work will be better understood by examining the drawing at the extreme roller Q for stretching the felting, where they are shewn, o and o being two wheels, fixed upon the ends of the screws p and p. The two wheels q and q are hung or fixed upon the spindle r, which, being turned by a handle at one end, gives motion to the

screws

screws in either direction by the teeth of the wheels taking into each other respectively. The roller C near the vat has its pivots resting upon, or turning in two carriages or supporters s and s affixed to a strong iron bar f, (which we call the shaking bar) supported by the two upright pieces of iron u and u, which are each connected with the shaking bar by a joint as at 2, and with the frame at bottom by another joint at w These joints admit of the bar being moved or shook backward and forward in a direction parallel with itself. The upright pieces or supports are furnished with screws near the bottom at x, by which the roller C and the under web may be set exactly level; yy, &c. are two straight iron bars, one on each side of the upper part of the under web, and parallel therewith, having their ends next the vat connected by means of a joint at z, with the iron carriages or supports A a placed upon and affixed to the shaking bar; the other end of the bars y and y, being in like manner connected with the iron carriages or supports Ab and A b affixed to the wooden posts A c. These we call the ruler bars, and to them are attached a number of wheels Ad Ad &c. (the peculiar construction and application of which will be shewn hereafter) for the purpose of conducting the undèr web in a proper direction, and likewise for keeping the same extended laterally. Upon the ruler bars are supported the dickles, by means of the five cross bars marked Ae; two of which pass through mortises made for that purpose in the upper dickles, and the other three through the under ones. Af, Af, &c. are screws by which the bars are connected to the ruler bars, and by which the upper and under dickles are adjusted and set parallel with each other, and with the under web. F and G are the dickles

with the revolving straps H and I. Ah and Ah are the pullies, upon which the straps revolve; the pullies A h - and Ah being made to revolve upon arbors or pins fixed to each dickle, as at Ai. The dickles are kept parallel with and at any determinate distance from each other by the screws Aj, by which they are fastened or held to the cross bars Ae. In order to prevent the pulp from adhering to the dickles, we line or cover them with plates of copper or brass on both sides and upon that edge which bears upon the strap. Ak and Al are two toothed wheels of equal diameters, taking or working into each other, and fixed or hung upon the two spindles Am and An, as seen in the section. The wheel Ak and spindle Am are likewise shewn upon the plan. The spindles Am and An are placed across the machine, one above and the other below the upper part of the under web, for the purpose of communicating motion to the revolving straps by means of the wheels Ao and Ap and the pulley Ag, round which the strap revolves. The wheel Ap is concentric with and affixed to the side of the pulley Ag. The other wheel Ao is hung or fixed upon the spindle Am. The frame work or arm by which the wheels Ao and Ap are held in connection with each other is so constructed, that one end swings or turns upon the outside of the extended socket of the wheel Ao, through which the square spindle Am passes (the outside of the socket being made round for that purpose).

In the other end of the frame or arm we fasten a round pin or arbor, its axis being parallel with the spindle; and upon this pin the wheel and pulley Ap and Ag turn; the teeth of the two wheels Ao and Ap take in each other, so that in whatever direction the arm and wheel Ap turn or move, the centre of the wheel and pulley Ap and Ag will

describe