A Dkcexxiai, Recokd 31 



A subject of tremendous importance, upon which comparatively 

 little work lias })ecn done so far is the fireproofing of wood through 

 painting or the injection of chemicals. The laboratory has developed 

 apparatus for the measurement of the inflammability of either natural 

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

 untreated wood of many species and of specimens treated with vari- 

 ous kinds of flreproofing agents. The relative value of several 

 methods of flreproofing has heen studied and a fireprooflng 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 -with 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 which have been in place for al)Out 15 

 years. Various treatments and various species of wood 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. Especial 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 lias had commercial application not only in the improvement of 

 specifications for preservatives. ])ut also in the modification of the 

 technique of plant operation. 



/// Kiln Drying and the PJn/sical Properties of Wood 



The artificial seasoning of wood, conmionly 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 tlie drying of species and sizes of mate- 

 rials M-hich did not readily respond to the generally unscientific proc- 



