2, BULLETIN 343, U. S. DEPARTMENT OF AGRICULTURE. 
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, ete. 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.! 
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 EHibel, 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. 7 
1 Copies of Forest Service Bulletin 127 may be procured from the Superintendent of Documents, Wash- — 
ington, D. C., for 15 cents each, 
