Current Literature 485 



Ground-Wood Pulp. By J. H. Thickens and G. C. McNaughton. 

 Bulletin 343, U. S. Department of Agriculture. Contribution 

 from the Forest Service. Washington, D. C. 1916. Pp. 151. 



This is a highly specialized and yet practical publication, 

 which in the official monthly list of publications is listed as "none 

 for free distribution and none for sale." Supposedly, those 

 commercially interested can secure it by special correspondence. 

 It is a supplement to Bulletin 127, on the grinding of spruce, 

 recording experiments not only on spruce, but besides a few hard- 

 woods on a nimiber (19) of other coniferous woods, eleven of which 

 are found suitable for the production of news print, while such 

 species as tamarack and Jack pine, owing to their dark color, do 

 not lend themselves to this use. 



A price curve of news print paper from 1878 on shows strikingly 

 the gradual substitution of the cheaper ground pulp for more 

 expensive paper materials; the price per 100 pounds in 1878 of 

 $7.25 having fallen in 1898 to less than $1.75. Other curves show 

 the movement of exports and imports. The equipment and 

 methods used in the experiments are described. The effects of 

 steaming, boiling, pressure, temperature, and time of cooking, 

 and other conditions in producing spruce pulp were investigated 

 with a view to increasing efficiency, reducing power consumption 

 and increasing yield per cord. 



Cooking prior to grinding produces stronger-fibered pulp, but 

 requires more power than untreated wood. No difference in 

 quality from steaming or cooking was observed. Under high 

 pressure the yield per cord in spruce is greater than at low. 



Maps show the distribution of the various species investigated. 

 In one appendix the results of tests are tabulated in detail, and 

 in another appendix paper samples from the various woods treated 

 in different ways are added, allowing the manufacturer or constmier 

 to judge the quality. 



B. E. F. 



Year Book, 1915. U. S. Department of Agriculture. Washing- 

 ton, D. C. 1916. Pp. 616. 



Too often the Year Book of the Department of Agriculture 

 immediately upon receipt is relegated to a top bookshelf. The 

 1915 volume has more of interest to the forester than usual. A 



