REPORT OF THE SECRETARY. 239 



paper. As a direct result of these experiments several mills have 

 begun grinding these woods. Moreover, the department has demon- 

 strated in its paper laboratories, which work under conditions com- 

 parable with those of practical manufacturing plants, that efficiency 

 in pulp making can be raised far beyond that which obtains in the 

 ordinary plant. 



WOOD DISTILLATION. 



In wood distillation the department has demonstrated that com- 

 mercial yields of acetate of lime and wood alcohol can be obtained 

 from various new woods and from mill waste of these woods. It 

 has also demonstrated that a yield of acetate of lime more than one- 

 half greater than the present can be obtained. There is now being 

 installed in the forest-products laboratory a still of special design, 

 contrived by our investigators for the production of ethyl alcohol 

 from wood waste. Only the methyl or wood alcohols are now so 

 produced. There is wasted in the United States each year 6,000,000 

 tons of slabs, edgings, and sawdust, each ton of which is capable of 

 yielding 15 gallons of alcohol, if the proper commercial process can 

 be developed. 



KILN-DRriNG. 



In the artificial seasoning, or kiln-drying, of lumber, lack of scien- 

 tific knowledge of what is involved and of accurate control of the 

 methods used has been a cause of heavv loss. The average amount 

 of material rendered unfit for use in kiln-drying is 3 per cent for 

 softwoods and 10 per cent for hardwoods, which means a money 

 loss of millions of dollars annually. After years of study the de- 

 partment has arrived at such a knowledge of the theory and prac- 

 tice of drying lumber as makes possible a dry kiln in which tem- 

 perature, circulation, and humidity of the air are under control of 

 the operator. This solves the fundamental problem. 



FOREST RESOURCES. 



When the tAventieth century opened the actual situation with re- 

 gard to forest supplies was a matterof entire uncertainty. The census 

 had published figures of lumber production at successive 10-year in- 

 tervals, but there was no knowledge of what supplies the country pos- 

 sessed or of the rate at which those supplies were replenished by 

 growth. In 1907 the Forest Service brought together from all existing 

 sources of information its first estimate of our actual forest resources. 

 This stock taking was carried further in the reports prepared for the 

 Conservation Commission. These figures, combined with the figures 

 of annual consumption, collection of which began in 1905, showed 

 for the first time to all the danger of an impending timber shortage. 



