A Decennial Record 31 



A subject of trciiR'iuloiis inij)()rt;iMcc, upon wliicli coiiipuratively 

 little work has been done so far is the fi reproofing of wood through 

 painting or the injection of clieniicals. The la})oratory has developed 

 apparatus for the measurement of the inflammability of either natural 

 or "lireproofed" wood and has studied the relative inflammability of 

 imtreated Mood of many species and of specimens treated with ^'ari- 

 ous kinds of flreproofing agents. The relative value of several 

 methods of flreproofing has been studied and a flreproofing paint de- 

 veloped. 



The final test of any wood-preserving process or material lies in 

 the results which it yields in actual service; no laboratory test can 

 simulate the widely varying conditions encountered in use wath suf- 

 ficient accuracy. Therefore, a large number of experimental tests of 

 treated timber have been placed throughout the country, principally 

 in cooperation with large consumers of timber. There are tests of 

 treated ties, poles, fence posts, mine timbers, wood block pavements, 

 and piling timbers, some of wdiich have been in place for about 1.5 

 years. Various treatments and various species of w^ood were used in 

 each case, and complete records of treatment and periodical inspection 

 kept. These records form the best available measure of the value of 

 various preservatives and preserving processes under ordinary service 

 conditions. 



The study and analysis of wood preservatives has been a major 

 project since the inception of the laboratory. Kspecial attention has 

 been given to the analysis and grading of coal-tar and water-gas-tar 

 creosote, and a number of refinements have been made in the art. This 

 work has had commercial application not only in the improvement of 

 specifications for preservatives, but also in the modification of tlie 

 technique of plant o^^eration. 



In Kiln Drying and the Plujsical Properties of Wood 



The artificial seasoning of wood, commonly called "kiln drying", 

 has been practiced by rule-of -thumb methods to a large degree for 

 many years; and in any event it was a commercial practice only with 

 comparatively easy drying conditions, since little progress had been 

 made in handling successfully the drying of species and sizes of mate- 

 rials which did not readily respond to the generally unscientific proc- 



