SAP-STAIN, MOLD, AND DECAY IN GREEN WOOD. 31 



sultry weather. The tile chamber, when given a preliminary treat- 

 ment, which consisted of intermittent steaming for three successive 

 days to reduce the amount of viable fungous growth therein, pro- 

 vided these conditions admirably. In this chamber the temperature 

 was maintained at an average of 85° F., while the relative humidity 

 varied from 70 to 95 per cent. At the end of four weeks in the tile 

 chamber the blocks were removed and their condition with respect 

 to molding noted. 



The following observations were made from several series of exper- 

 iments : 



The amount of drying which took place in the steam box was comparatively 

 slight. This seemed to depend, however, upon the relative moisture content of the 

 wood previous to steam- 

 ing. Green blocks usu- I I I i 

 ally lost, while partly f^(^(^<<^ i ^^^^^ i 

 seasoned blocks often jr^/^/^<^| JAP>^<^ 

 gained in weight. /f;^ ^ or, ^ 



Beyond a certain '/^^^J 'a<^/^^' %/^n>,.^ 



length of time dependent W?^ h;?;!!;^ W;^ 



upon the moisture con- i "^ 1 1 '' I I " """"^ 



tent of the wood and f^fis(^<^ | '^'^^'^ f^^(^<<^ - 



the surface area of the A x?^ /^ <^ h> ^ 



blocks in relation to vol- '^a^^J V!N/Nfe^ WaJ U>4S^c^^ 



ume, there seemed to be Wj^ W:^ Wm^ W^ 



little gamed, in so far as 1. — J I — I I , . I I , .1 



the reduction in weight g^ |^^ ^^ P^ 



was concerned, by con- mT^ M, <M ^ iM ^ M, 



tinned steaming. Six or 



nine hours' steamin<' ^^"^^ ^^- — Diagram illustrating one method of stacking 

 , '^ green split billets. This method is used by one of the 



seemea to be no more ^^j.^^ ^j^^^j factories of the North. When ample storage 



efficient than three hours space in well-ventilated sheds is available, this method 



in the case of the 24 by is recommended. 



2^ by 10 inch blocka 



Steamed blocks subsequently dried more rapidly than those that were simply 

 air-dried. 



Open piling or stripping in the steam box was preferable, in that it per- 

 mitted a better circulation of the steam in the box and thus insured a more 

 uniform treatment of the blocks. 



The amount of checking varied in the several lots when steamed under the 

 same conditions. This may have been due to the fact that the blocks differed 

 considerably in the relative proportion of sapwood and heartwood present. 



The greatest amount of checking occurred in those lots that were subjected 

 to rapid cooling and surface drying by exposure to air currents from open doors 

 and ventilators. Blocks allowed to cool in the steam box with doors closed 

 seemed to suffer least in this regard. Slow cooling was, in some cases, brought 

 about by opening a small hatch in the roof of the steam box at the conclusion 

 of the steaming period. 



The total amount of checking which had taken place in the steamed blocks, 

 both during the steaming process and the subsequent period of air seasoning, 

 extending over four months, exceeded but little that noted in those blocks which 

 had been simply air seasoned for the same length of time. 



Steaming seemed to be effective in killing the fungi in the infected blocks 

 when employed for a period of three hours. Cultures taken from various points 



