PAPER, MANUFACTURE OP 



491 



tinuous folt, s, which conducts it through two pairs of pressing-rollers, and after- 

 wards to the drying-cylinders. After passing through the first pair of rollers, the 

 paper is carried along tho felt for some distance and then turned over, in order 

 to receive a corresponding pressure on the other side, thus obviating the inequality 

 of surface which would otherwise be apparent, especially if the paper were to be 

 employed for books. 



The advantage gained by the use of so great a length of felt is simply that it 

 becomes less necessary to stop the machine for the purpose of washing it, than would 

 be the case if the felt were limited in length to its absolute necessity. 



In some instances, when tho paper being made is sized in the pulp with such 

 an ingredient as resin, the felt becomes so completely clogged in the space .of a 

 few hours, that unless a very great and apparently unnecessary length of felt bo 

 employed, a considerable waste of time is constantly incurred in washing or changing 

 the felt. 



The operation of tho manufacture will now be apparent. The pulp flowing from 

 the reservoir into the lifter, and thence through the strainer, passes over a small lip 

 to the continuous wire, being there partially compacted by the shaking motion, more 

 thoroughly so on its passage over the air-boxes, receiving any desired marks by means 

 of the dandy-roller passing over the continuous felt between the first pressing-rollers, 

 then turned over to receive a corresponding pressure on the other side, and from 

 thence off to the drying-cylinders, which are heated more or less by injected steam ; 

 the cylinder which receives the paper first being heated less than the second, the 

 second than the third, and so on ; the paper, after passing over those cylinders, being 

 finally wound upon a reel, as shown, unless it be printing-paper, which can be sized 

 sufficiently in the pulp by an admixture of alum, soda, and resin, or the like; in 

 which case it may be at once conducted to the cutting-machine, to be divided into any 

 length and width required. But, supposing it to be intended for writing purposes, it 

 has first to undergo a more effectual method of sizing, as shown in tho accompanying 

 drawing; the size, in this instance, being made from parings obtained from tanners, 

 curriers, and parchment-makers, as employed in the case of hand-made papers. Of 

 course, sizing in the pulp or in the engine offers many advantages ; but as gelatine, or 

 animal size, which is really essential for all good writing qualities, cannot at present 

 be employed during the process of manufacturing by the machine without injury to 

 the felts, it becomes necessary to pass the web of paper, after it has been dried by the 

 cylinders, through this apparatus. 



In most cases, however, the paper is at once guided as it issues from the machine, 

 through the tub of size, and is thence carried over the skeleton drums shown, inside 

 each of which are a number of fans rapidly revolving ; sometimes there are forty or 

 fifty of these drums in succession, the whole confined in a chamber heated by steam. 



A paper-machine, with the sizing-apparatus attached, sometimes measures, from the 

 wire-cloth, where the pulp first flows on, to the cutting-machine at the extremity, no 

 less than 1,000 feet. The advantage of drying the paper in this manner over so 

 mauy of these drums is, that it turns out much harder and stronger than if dried 

 more rapidly over heated cylinders. Some manufacturers adopt a peculiar process of 

 sizing, which, in fact, answers very much better, and is alike applicable to papers 

 made by hand or by machine, provided the latter description be first cut into pieces or 

 sheets of the required dimensions. The contrivance consists of two revolving folts. 

 between which the sheets are carried under several rollers through a long trough of 

 size ; being afterwards hung up to dry upon lines previously to rolling or glazing. 

 The paper thus sized becomes much harder and stronger, by reason of the ireedom 

 with which the sheets can contract in drying ; and this is mainly the reason why 

 paper made by hand continues to be so much tougher than that made by the machine. 



