REPORT OP THE FORESTER. 197 



Makers of pyrometers are now actively advertising the method of 

 controlled distillation developed by the laboratory. It is believed 

 that at least 50 per cent of the plants arc attempting to use tliis 

 method. Increased production is impoitant because of the demand 

 for the products in munitions making. One year's experiments indi- 

 cate that the yield of naval stor6s can be increased by 30 per cent 

 or more by making two narrow rather than one broad streak per 

 week, as in connnercial practice, and that net returns per crop cnn 

 be increased by about $450. The same trees are being chipped for 

 the second year to determine if the yield will be maintained. Double 

 chipping should be especinlly applicable in the case of lumber com- 

 panies Avhich desire to obtain maximum yields for a short period 

 prior to cutting. 



In the chemical survey of woods the mannan content was deter- 

 mined for 22 softwoods and 6 hardwoods. This is important, be- 

 cause of its relation to the yield of eth,yl alcohol. 



Further study of the utilization of various waste barks for the 

 manufacture of pulp and paper products included that of 8 species. 

 Observations over a period of six months failed to show any marked 

 signs of depreciation in paper and board made on a furnish of 

 hemlock tanbark stored under ordinary conditions. Cooperative 

 work is under way to determine the commercial practicability of 

 using the various barks in a number of paper products. Tests under 

 the soda process were continued for 13 species. Bleaching tests were 

 also made on a number of these pulps. Similar tests by the sulphite 

 process, which supplies a part of the material used in news print, 

 were made on 12 species, and some work was done to devise a method 

 which will permit the sulphite pulping of resinous woods. A study 

 of fundamental variables in the sulphite process, under way for a 

 number of years, was completed. Tests under the sulphate process 

 were continued in 18 species, and a good grade of kraft pulp, suitable 

 for a high-test wrapping paper, was obtained from each. 



INDUSTRIAL INVESTIGATIONS. 



On the whole, the principal activity of the Office of Industrial In- 

 vestigations for the year was in cooperation on war problems along 

 lines already mentioned. To a smaller extent the efforts of the force 

 followed the usual channels, including the collection of industrial 

 statistics. Through cooperation with the National Lumber Manu- 

 facturers' Association it was possible to collect data and issue a 

 report on the production of lumber in 191G. Production was esti- 

 mated at approximately 40,000,000,000 board feet, from over 30,000 

 sawmills. Though hampered by lack of shipping facilities in many 

 regions and by scarcit}' of labor at many small mills, the active mills 

 increased in number, and the total lumber cut amounted to nearly 

 2,000,000,000 feet more than in 1915. 



For the first time since 1911 statistics were compiled and reports 

 issued showing the number of crossties and poles purchased in the 

 United States. Approximately 121,400,000 crossties were purchased 

 in the calendar year 1915 — 112,800,000 by steam railroads and 8,600,- 

 000 by electric railways and light, heat, and power companies. The 

 total number of poles purchased was 4,078,000. 



In cooperation with the American Wood Preservers' Association, 

 statistics were collected showing that in 1915 a total of 150,500,000 



