Current Literature. 237 



heat to enter the load are the essentials of rapid and uniform 

 drying- 



4. Preliminary steam baths are of great value in reducing 

 checking, casehardening and warping; for drying in no case 

 should be permitted to proceed unless conditions are such that 

 the moisture will be brought from the interior of the board as 

 rapidly as it is removed from the surface. 



5. Artificial circulation greatly accelerates and equalizes the 

 rate of drying in flat piled loads. 



6. Vertical stacking greatly accelerates and equalizes the rate 

 of drying in kilns relying upon natural circulation by affording 

 uniform distribution of heat. 



7. Rapid or appreciable exchange of air in the kilns for carry- 

 ing away the evaporated moisture, or condensing apparatus for 

 disposing of this moisture, is not essential to quick drying, even 

 at temperatures 10 or 20 degrees below the boiling point. 



8. The practice of using wide pieces of flooring strips for 

 stickers should be abandoned, for they greatly retard drying in 

 that portion of the board covered by them. Flooring strips so 

 used, often being manufactured, frequently shrink at the points 

 where they were in contact with other boards, giving manu- 

 factured board incavated edges at such points. 



9. There is room for improvement in the method of binding 

 vertical stacked loads, in which there is a small amount of 

 warping. 



10. The time required for drying lumber at nearly all kilns 

 visited may be greatly reduced by one or more of the following 

 means : More open piling, vertical stacking, higher temperatures, 

 conservation of heat, constant temperature, separation of species, 

 and discontinuance of the practice of drying lumber to an un- 

 necessarily low moisture content. 



11. All factors which tend toward uniformity in drying con- 

 ditions on the two sides of the boards and throughout the truck 

 materially increase the efficiency of the kiln. 



S. J. R. 



