490 PAPER, MANUFACTURE OF 



water which drains away from the pulp during tho process of manufacture, and as this 

 water is frequently impregnated -with certain chemicals used in connection with paper- 

 making, it is returned again by a conducting spout, into the ' lifter,' where, by the 

 rotation of the buckets, both the pulp and back-water become again thoroughly mixed, 

 and are together raised by the lifter through the spout, L, into the trough, M, where 

 tho pulp is strained by means of a sieve or ' knottcr,' as it is called, which is usually 

 formed of brass, having fine slits cut in it to allow the comminuted pulp to pass 

 through, -while it retains all lumps and knots ; and so fine are these openings, in order 

 to free the pulp entirely from anything which would be liable to damage the quality 

 of the paper, that it becomes necessary to apply a means of exhaustion underneath, in 

 order to facilitate the passage of the pulp through the strainer. 



The lumps collected upon the top of this knottcr, more particularly when printing- 

 papers are being manufactured, are composed to a considerable extent of india-rubber, 

 which is a source of much greater annoyance to the piper-maker than is readily con- 

 ceived. For, in the first place, it is next to impossible in sorting and cutting the rags 

 to free them entirely from tho braiding, and so forth, with which ladies adorn their 

 dresses ; and, in tho next, the bleach failing to act upon a substance of that character, 

 tho quality of the paper becomes greatly deteriorated by the large black specks which 

 it occasions, and which, by the combined heat and pressure of the rolls and cylinders, 

 enlarge considerably as it proceeds. 



Passing from tho strainer, the pulp is next made to distribute itself equally 

 throughout the entire width of the machine, and is afterwards allowed to flow over 

 a small lip or ledge, in a regular and even stream, whence it is received by the 

 upper surface of the endless wire, x, upon which the first process of manufacture 

 takes place. Of course the thickness of the paper depends in some measure upon 

 the speed at which the machine is made to travel, but it is mainly determined by 

 the quantity of pulp allowed to flow upon the wire, which, by various contrivances, 

 can be regulated to great nicety. Paper may be made by this machine consider- 

 ably less than the thousandth of an inch in thickness, and, although so thin, it is 

 capable of being coloured, it is capable of being glazed, it is capable of receiving 

 a water-mark ; and, what is perhaps still more astonishing, a strip not exceeding 

 4 inches in -width is sometimes capable of sustaining a weight of 20 Ibs., so great 

 is its tenacity. 



But to return to the machine itself. The quantity of pulp required to flow from 

 the vat, M, being determined, it is first received by tho continuous woven wire, K, 

 upon which it forms itself into paper ; this wire-gauze, which resembles a jack-towel, 

 passing over the small copper rollers, N, round the larger one, marked o, and being 

 kept in proper tension by two others placed underneath. A gentle vibratory motion 

 from side to side is given to the wire, which assists to spread the pulp evenly, and 

 also to facilitate the separation of the water ; and by this means, aided by a suction- 

 pump, the pulp solidifies as it advances. The two black squares on either side of the 

 ' dandy ' roller, p, indicate the position of two wooden boxes, from which the air is 

 partially exhausted, thus causing the atmospheric pressure to operate in compacting 

 the pulp into paper, the water and moisture being drawn through the wire and the 

 pulp retained on the surface. 



Next, we have to notice the deckle or boundary straps, Q, which regulate the width 

 of the paper, travelling at the same rate as the wire, and thus limiting the spread of 

 pulp. The ' dandy ' roller, p, is employed to give any impression to the paper that 

 may be required. We may suppose, for instance, that the circumference of that roller 

 answers exactly to tho length or breadth of the wire forming a hand-mould, which, 

 supposing such wire to bo fixed or curved in that form, would necessarily leave the 

 same impression as when employed in the ordinary way. Being placed between the 

 air-boxes, the paper becomes impressed by it when in a half-formed state, and what- 

 ever marks are thus made the paper will effectually retain. The two rollers following 

 the dandy, marked B and o, are termed couching-rollers, from their performing a 

 similar operation in the manufacture of machine-made papers to the business of 

 the coucher in conducting the process by hand. They are simply wooden rollers 

 covered with felt. In some instances, however, the upper couch-roll, B, is made to 

 answer a double purpose. In making writing- or other papers where smalta, ultra- 

 marine, and various colours are used, considerable difference will frequently be 

 found in the tint of the paper when the two sides are compared, in consequence of 

 the colouring-matter sinking to tho lower side by the natural subsidence of the water, 

 or from the action of the suction-boxes ; and, to obviate this, instead of employing 

 tho ordinary couch-roll, which acta upon the upper surface of the paper, a hollow 

 one is substituted, having a suction-box within it, acted upon by an air-pump, which 

 tends in some measure to counteract the effect justly considered as objectionable. 

 Merging from these rollers, tho paper is received from the wire-gauze by a con- 



