FOREST UTILIZATION 95 



IV. The daily capacity of an eight block machine is 4,000 



pounds of fine wood wool, or 10,000 pounds of mattress 



stock. 

 V. Additional machinery consists of automatic knife grinders, 



baling presses, cut off saws etc. 

 VI. The price of the machinery for a modern plant is about 



$2,000. About 30 horsepower are required. 



XXXI. GROUND WOOD PULP AND CHEMICAL FIBRE AND THEIR MANUFACTURE. 



A. Historical remarks. 



Up to 1854 paper was made from cotton, linen and hemp fibre, 



precipitated from a mush in the shape of a matting. 

 Wood grinding was invented in 1854. Since 1867 the ground wood 



is refined by chemical processes which separate the wood 



into thinner strings of cells and free it from rosin, tannin, 



albumen, gums etc. 

 In the United States there were, in 1890, 82 mills producing 



$4,600,000 worth of wood paper, while the value of the output in 



looo approximated $20,000,000. 

 Rags, manila, straw and waste paper used as raw material for 



paper still outrank in value (in 1000) the wood used as raw 



material. 

 In 1000, close to 2,000,000 cords of wood were consumed, worth 



nearly $10,000,000; three-fourths being spruce and one- fourth 



poplar and miscellaneous. 

 If the United States shall conquer the Swedish and German export 



and supply the entire consumption of wood paper at home, 



6,000,000 acres of well managed wood lands will be required to 



produce the raw material. 



B. Statistical remarks. 



One cord of wood yields one ton of ground pulp wood (mechanical 



fibre) or }/ ton of chemical fibre. In the so called "news grade" 



80% of pulp is mixed with 20% of chemical fibre. 

 Japanese paper is made of the inner bark of a mulberry tree 



(Brussonetia). 



For highest grades of writing paper, cotton and linen arc used. 

 An average mill produces 25 tons a day. 

 A modern pulp plant requires annually, at least, 6,000 cords of 



wood ; a modern fibre plant at least 25,000 cords. 

 The price of the product loco factory is about : 



For ground wood pulp, $13 per cord; 



For soda fibre, $20 per cord ; 



For sulphite fibre, $25 per cord. 



C. The plant. 



The plant requires an outlay of about $ib,ooo per ton of daily 

 production. Unlike a saw mill, a paper mill cannot be shifted 

 when the nearby supply of raw material is exhausted. 



