FOREST SERVICE. 425 



eacli line of work are classified in two <.;roups, of which the first con- 

 stitutes those regarded as of major importance, the second those less 

 important at the present time. 



In timber tests the projects of major importance are: Tests to 

 determine the effect on the strength of wood of solutions used for 

 the })revention of sap stain; standard tests to determine the relative 

 mechanical })roperties of the commercial woods of the United States; 

 tests to determine the effect on the mechanical properties of wood of 

 preservatives and preservative treatment ; tests on built-up axles and 

 hubs, and tests to determine the effect of different kinds and stages 

 of decay on the mechanical properties of wood. 



Minor projects are: Tests to determine the mechanical efficiency of 

 joints and fastenings used in wooden structures; tests of the strength 

 of built-up beams in comparison witli that of solid beams; tests of 

 vehicle and implement parts made of various species of eucalyptus; 

 tests of the holding power of railroad spikes of various forms in various 

 kintls of wood; tests to determine the relative strength of wood under 

 dead, impact, and re])etitive loading; tests of the relative strength of 

 different kinds of wire-bound, veneer, and fiber-board boxes; tests 

 of the relation between mechanical properties of Rocky ^fountain 

 woods and conditions affecting growth, such as soil, altitude, etc.; 

 tests of the strength of structural timbers of Western hemlock and of 

 green and fire-kiffed Douglas fir; strength tests of Western larch and 

 aspen, and tests of Western hemlock and Douglas fir. 



In wood preservation the major projects are the following: The 

 preservative treatment of cross-ties; the effectiveness of different 

 fractions of coal-tar creosote in preventing decay and in preventing 

 the attacks of marine borers; the preservative treatment of silo 

 timbers; the efficiency of different wood preservatives; experimental 

 study of mechanical features of wood-preserving processes, including 

 study of preliminary steaming, temperature of preservatives, pressure, 

 and vacuum; prevention of sap stain; and the relative resistance of 

 different species of wood to preservative treatment. Minor projects 

 are: Determination of the quantity and character of distillates 

 obtained from the treating cylinder during a hot bath; determina- 

 tion of the possibility of substituting treated gum for locust and 

 other woods used for insulator pins; determination of the rate at 

 which different grades and quantities of preservatives in wood lose 

 their efficiency when exposed to the air only, when in contact with 

 the soil, when underground, and when submerged under water; 

 determination of the effect of moisture content, rate and condition of 

 growth, and presence of bark upon the impregnation of wood with a 

 preservative; and various projects in the experimental treatment 

 of fence posts, poles, lumber, mine timbers, and paving blocks, and 

 the construction and operation of treating plants of A'arious kinds. 



In timber physics the major ))rojects include: Determinations of the 

 specific heat of wood and wood substance and of the heat conduc- 

 tivity of wood under diOerent conditions; methods of drying and 

 conditioning lumber of {JiU'ereiit kinds and for dillerent purposes; 

 investigation of the fundamental laws of drying and of absorj)tion; 

 microscof)ic study of the structure of the principal native commer- 

 cial \\()ods and of the relation of structure to jjhysical and mccliaiu- 

 cal properite.s; the effect of temperature upon the strength and 



