MANUPACTUKES, ETC. 243 



the sulphite process." Other varieties which 

 come on the market in smaller quantities are 

 Birch, Red Beech and American Chestnut. " For 

 soft absorbent papers, such as blottings and 

 copper plate printings, Poplar and Aspen are 

 employed to a considerable extent as excellent 

 substitutes for the soft cotton rags generally 

 used in the more expensive grades." 



The method of preparation is used as a basis 

 for the classification of the coniferous wood 

 celluloses ; they may be soda or sulphite pulps, 

 and these again are divided into " strong " or 

 low-boiled and " easy bleaching " or high-boiled 

 types. 



The practically transparent grease-proof and 

 imitation parchment papers are prepared by 

 " beating ' strong ' wood pulps between very 

 broad, blunt knives for about twelve hours, with 

 the object of crushing and shredding the fibres 

 rather than cutting them, thereby forcing the 

 water into combination with the cellulose, so 

 that the latter is gradually reduced to a gela- 

 tinous mass. It may be assumed that if any 

 considerable degree of strength and elasticity 

 is to be retained in the paper, care niust be taken 

 to avoid the ' dead ' beating of the fibres during 

 this very severe treatment, and that the length 

 of the fibres should be maintained as far as 

 possible, although in such extreme cases ascertain 



