58 ThK FoKKST PkODUC'IS liAUOKATOKV 



ill many ways. The great l)ulk of the work carried out l)y the wood- 

 microscopy speciahsts during tlie war consisted in the identification 

 (as to species) of samples of wood for the hd)()ratory and for various 

 agencies and manufacturers engaged upon war M'ork. ()\'er 18. 000 

 specimens were thus identified during the war. One of the most re- 

 markable series of identifications was of gas mask charcoals submitted 

 by the Bin-eau of Standards early in the Avar. It was possible, ])y the 

 use of the identification keys M-orked out before the war, to identify 

 the species of wood from which each sample of charcoal had been made. 



A distinct phase of tlie microscopic work was the examination of 

 wood for decay. There are many kinds of stain and discoloration 

 caused by various agencies, among which are certain decay-])roducing 

 organisms. It is frequently impossible to determine the origin of a 

 stain except under the microscope, and it is most important, especially 

 in aircraft work, tliat no wood be used which is even slightly decayed 

 and. almost as im])ortant, that no wood be rejected simply on suspicion 

 of decay. 



Manufacturing and ])urchasing specifications of the leaders in 

 industry usually embody in a few simple words the residts of years 

 of study and experience and they represent the latest and best prac- 

 tice. Much of the progress made by the laboratory in its ten years of 

 research is embodied in the specifications of the various Army and 

 Navy bureaus and of the leading manufacturers in many industries 

 using wood. Several hundred such specifications were referred to the 

 laboratory for criticism and revision, and of these a goodly share were 

 written practically in their entirety at the laboratory. 



Instructional work afforded another excellent means of making 

 the laboratory's knoM'ledge effective. The staff had been doing in- 

 structional work of various kinds for a number of years and was 

 therefore well qualified to undertake the instruction of various grades 

 of inspectors and o])erators. The first course for airplane inspectors 

 was given in .Tidy, 11)17, and succeeding courses at intervals of two or 

 three weeks imtil the close of the war. xVbout 12.5 men received in- 

 struction in these courses, exclusive of various of the newer members 

 of the laboratory staff. 



Courses of instruction for box inspectors, principally for the 

 Ordnance Department, were inaugurated at about the same time as 

 those for airplane inspectors, and contiiuied until after the cessation 



