18 The Forest Products Laboratory 



feet. While this indicates the niuxiiniini caj^acity of the Forest Prod- 

 ucts Laboratory to test timbers and huge built-up members, the equip- 

 ment for lesser parts is especially complete. Ten machines capable 

 of applying breaking strains of from 10,000 to 200,000 pounds are 

 also available. Toughness and impact resistance are measured on 

 other machines, while many special tools and rigs are here for special 

 tests, including those for testing plywoods. Most of these machines 

 are original devices that first saw the light of day in the la])oratory 

 as need for them arose in the progress of the development of the 

 technique of testing wood. 



The box laboratory, a part of the work of timber mechanics, is 

 equipped with two tumbling drums, the larger of which can take boxes 

 M'eighing as much as half a ton, and reduce them slowly or quickly to 

 a shattered wreck — the quickness of the breaking depending on the 

 amount of resistance built into the box by its designers. Here also 

 can be measured the abihty of a box to stand tension and compression, 

 drop tests and similar abuse. 



Tlie drying of wood by almost any conceivable variation of tem- 

 perature, humidity and circulation within practical limits is possible 

 in the laboratory equipment of six dry kilns of commercial size, all 

 closely regulated and entirely automatic and autographic in their 

 operation. In addition to the kilns, a conditioning apparatus permits 

 fundamental research in the conditioning and treating of wood under 

 pressures or gases, and under absolutely controlled factors. This 

 apparatus, as well as the kilns and many supplemental devices, was 

 designed by laboratory engineers. 



Completely equipped to make wood pulp by any of the commer- 

 cial chemical or mechanical processes and convert the pulp into paper 

 by cylinder or Fourdrinier process, the pulp and paper section meas- 

 ures up to the general standards of equipment existing throughout the 

 laboratory. The list of equipment sounds like a combination of several 

 paper-making plants, but of course ever}i;hing is on a laboratory 

 rather than on a commercial scale. The main items recognizable by 

 the paper manufacturer are a wood chipper, sulphite and soda digesters 

 and necessary auxiliaries, grinder, pulp press, wet machine, beaters, 

 Jordan and a 22-inch combination cylinder and Fourdrinier paper- 

 making machine. Pressers, driers, colenders, etc., complete the list. 

 In addition to complete chemical equipment, a constant humidity and 



