2 BULLETIN" 343, U. S. DEPAETMEISTT OP AGBICULTTJRE. 



variable conditions in the manufacture of mechanical pulp, such 

 as surface of stone, pressure with which the wood is forced upon it, 

 peripheral speed, temperature of grinding, etc. Since the conclusions 

 reached in regard to these are applicable to the production of pulp 

 from coniferous woods in general, it is advisable to have a copy of 

 Bulletin 127 at hand when reading the present one. 1 



All the tests described in this bulletin were carried on at the Forest 

 Service ground-wood laboratory at Wausau, Wis., a branch of the 

 Forest Products Laboratory, Madison, Wis., in cooperation with the 

 American Paper and Pulp Association, which furnished all the 

 pulp-making equipment for the laboratory, and with an advisory 

 committee consisting of Messrs. G. F. Steele, chairman, and W. G. 

 McNaughton, secretary, Nekoosa-Edwards Paper Co. ; D. C. Everest, 

 Marathon Paper Mills Co.; W. L. Edmonds, Wausau Paper Mills 

 Co.; A. M. Pride, Tomahawk Paper Co.; and William Eibel, Rhine- 

 lander Paper Co. 



PRESENT STATUS OF THE GROUND- WOOD INDUSTRY. 



Thirty-five to forty-five years ago news paper was made almost 

 entirely of rags. Upon the introduction of the sulphite process of 

 wood-pulp manufacture varying amounts of that product were 

 added to the rag pulp, and later ground wood was made a part of 

 the mixture, but only in small quantities. Ground wood was for 

 many years nothing more nor less than a filler and not expected to 

 add any strength to the sheet produced. There is shown in figure 1 

 the average contract price (f. o. b. mill) of news-print paper from 

 1874 to 1912. The effect of the introduction of the cheaper processes 

 is evident. 



In 1870 there were only 8 establishments reported which made 

 ground wood, and the product manufactured during that year was 

 valued at $172,000. Ten years later, in 1880, 50 establishments 

 produced $2,257,000 worth of ground wood. In 1890, 82 establish- 

 ments reported products valued at $4,628,000. In 1900 there were 

 91 plants reported, which produced 280,520 tons of ground wood 

 for sale, and 77 mills which produced 306,520 tons of pulp for their 

 own use, a total of 168 mills, producing 586,000 tons, valued at 

 approximately $9,300,000. In 1909 there were produced a total of 

 1,179,266 tons of mechanical pulp. Of this amount 310,747 tons 

 were manufactured for sale or consumption in mills other than where 

 produced, the value being $5,649,466. The remainder, 868,519 tons, 

 assumed to have the same value of that made for sale, was worth 

 approximately $15,780,000, or a total value of product of $21,430,000. 



1 Copies of Forest Service Bulletin 127 may be procured from the Superintendent of Documents, Wash- 

 ington, D. O, for 15 cents each. 



