188 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



less than 1 per cent. These processes have been developed on a 

 semicommercial scale. The drying of maple shoe lasts, of which a 

 great number are used in the United States, has been difficult because 

 of the size of the blocks from which they are manufactured. On a 

 semicommercial scale the period required for drying has been reduced 

 to 7 weeks from nearly 2 3 T ears without increased loss. 



The dyeing principle of the Osage-orange wood was not used prior 

 to the investigations conducted in the laboratory. The value of this 

 material has been so conclusively shown that from $750,000 to 

 $1,000,000 worth of the dye is now being manufactured annually in 

 the United States and practically all from material which was for- 

 merly wasted. 



Approximately 12 per cent of the volume of the tree is bark. Little 

 use has been made of bark except as the source of tanning extract 

 and for fuel, and for the latter purpose the value has been very low. 

 Investigations conducted at the laboratory have resulted in the use 

 of spent tanbark in the manufacture of asphalt shingles to the extent 

 of 160 tons per week. The value of this bark has thereby been in- 

 creased from 60 cents to $2.50 per ton. This is one of a series of very 

 promising investigations to use a material formerly wasted. 



A new process has been developed on a semicommercial scale for 

 the manufacture of kraft or wrapping paper, and the suitability of 

 13 National Forest species for its manufacture has been shown. In 

 addition to improving the quality and increasing the strength, the 

 process promises reduced costs of at least 10 to 15 per cent and 

 increased yields of at least 5 per cent. Paper has been manufac- 

 tured which exceeds in strength and appearance any which it has 

 been possible to secure from American or foreign sources. 



A very considerable number of promising methods and processes 

 have now been developed on a semicommercial scale and their indus- 

 trial application awaits only tests on a commercial scale. In this 

 important phase of its investigations, the logical consummation of 

 all primary investigations, the efforts of the laboratory are greatly 

 handicapped through inadequate funds. This list includes the 

 manufacture of kraft paper from a considerable number of species, 

 including southern yellow pine, western yellow pine, Douglas fir, 

 etc.; improved processes of kiln-drying southern pine, red gum, 

 western larch, and other species; a process of purifying the sulphate 

 turpentine secured in the manufacture of kraft pulp from longleaf 

 pine; the use of sodium fluoride to prevent blue stain; and the manu- 

 facture of wallboard from spruce bark. 



Other developments of importance as a result of the investigations 

 of the laboratory during the year are the adoption by a number of 

 lumber companies of the improved grading rules for southern pine 

 structural timber, previously adopted by the Southern Pine Asso- 

 ciation; the development of similar rules in a preliminary form for 

 Douglas fir structural timber; development of a method on a semi- 

 commercial scale for removing casehardening in kiln-dried lumber; 

 studies which indicate precautions which should be used in .the 

 selection of timber to prevent decay in buildings; demonstration of 

 the fact that staves treated with creosote may be used in silo con- 

 struction without injury to stock; adoption by approximately 40 per 

 cent of the plants in the United States of improved methods of hard- 

 wood distillation developed by the laboratory and demonstrated on 



