66 THE I'RINOIPAI. USBS OF WOOD. 



displace the fibres to such an extent that a little twisting suffices 

 to separate these last from one another. In this condition the 

 fibres may be spun and woven like cotton or flax. 



A.ETICLE 19. "Wood pulp. 



Paper consists of cellulose with some sizing substance added in 

 order to prevent ink from running. Hence, if we remove from 

 wood everything but its cellulose, we get paper-making material, 

 or, as it is called, paper stock. Paper made entirely of wood stock 

 is, with the sole exception of that manufactured from young half- 

 lignified bamboos, rather brittle and coarse-grained ; but, on 

 the other hand, it takes a cleaner impression and wears away the 

 type less than printing paper made from linen or cotton rags. 

 Moreover, wood pulp is very much cheaper than stock prepared 

 from rags. Mr. Routledge, the great paper manufacturer, made 

 samples of paper from bamboo stock, which were equal to the finest 

 qualities of linen and esparto paper. 



Wood pulp is not only used by the paper manufacturer, but 

 serves for a variety of other purposes. By penetrating it with 

 special glutinous substances and subjecting it to high pressures, it 

 can be made as hard and as durable as one pleases, and be moulded 

 to any shape. Picture-frames, toys, ornaments, &c., are thus 

 made ; also slabs, which may be substituted for boards and planks, 

 and are practically unbreakable, and cannot warp or split even in 

 the most trying surroundings. In America solid railway-wagon 

 wheels are made of a skeleton of steel with specially prepared 

 wood pulp forced in between under great pressure. Such wheels 

 last very much longer than purely iron or steel wheels, and, being 

 of much more elastic material, produce very little jar, and minimise 

 wear and tear of the rolling stock and permanent way. The loose 

 fibre is used for stuffing cushions, as packing material and for 

 filtering water. 



The pulp may he made either (I.), by physical means, by rending 

 asunder the fibres between grind-stones, or (II.), by separating the 

 fibres chemically by maceration. 



I. The Physical PEOCiSSS.— The wood should be fresh-cut. It 

 is first barked, divided into short sections, about a foot long, and 

 split up, all knots and decayed portions being removed. The small 

 pieces are then broken and ground up in the mill, through which 

 a constant stream of water is kept flowing. The water carries 

 off" the broken fibre and dissolves away all clogging substances. 

 The coarser portions carried down by the water are separated by 



