Wooden Paper 



Vat. The steam pressure is increased above, and the mass is 

 driven out by the blast, leaving the walls of the digester as clean 

 as if they had been scrubbed. 



The cooking has chemically freed the wood fibre from every- 

 thing else. It remains to get the delicate white threads separated 

 from the mass of waste with which they are now associated in the 

 vat. Washing and screening are the means of freeing the fibres. 

 The processes now are purely mechanical. Water is introduced, 

 and by churning and draining alternately the acid solution is 

 washed out. Then the pulp passes, thinly spread, over sets of 

 screens that take out the coarsest of the impurities, brown flakes 

 of pith rays, uncooked knots, and bits of foreign matter. 



Water streams over and through the screens, carrying the 

 fine white fibres with it. There is a wide, endless apron of linen, 

 like a gigantic roller towel, that revolves at right angles with 

 the screening tables. As the water pours over this the fibres 

 lodge on the cloth, and as the dripping, tightly stretched sheet 

 of linen passes between the two big steel rollers at the end the 

 filmy layer of fibres has most of the water squeezed out, and 

 adheres as a damp, matted sheet of cotton wool to the upper 

 wheel. 



A continual winding of this coating of fibres thickens the 

 roll on the steel cylinder until it is like table felt of heavy quality. 

 The machinery need not stop while it is removed. A pocket 

 knife is run from end to end of the cylinder of steel. The next 

 revolution lays the white sheet of sulphite on the table in front of 

 the machine. The thin film on the steel is the beginning of another. 



This is sulphite. It has the colour of unbleached linen or 

 muslin. In fact, it looks much like felt, its fibres being merely 

 pressed together — not woven. It is folded clumsily and stacked 

 for the present. In this form it dries gradually for use or ship- 

 ment later, or it may be used at once. 



The Making of Paper. In this mill manufacture goes further 

 than in many. Sulphite is made into paper. Not the highest 

 grades, for the refuse of a woollen mill up stream pollutes the 

 water, so that an expensive system of filters would be required if 

 the manufacture of the better papers were attempted. 



The first step in the process of paper making is to bring out 

 the rolls of sulphite and throw them into a tank with plenty of 

 water. A central revolving shaft bears heavy arms under water 



546 



