. [Bulletins on forest pathology : from Bulletin , Washington, , 1913-1925]. Trees; Plant diseases. 30 S. DEPARTMENT OF AGRICULTURE. A steam box was constructed of cypress, equipped with thermome- ters, dew-point apparatus, and manometer and connected with the main which supplies steam to the laboratory greenhouse (figs. 15 and 16). By means of suitable reducing valves in the connecting pipes it was possible to control the steam pressure in the box; hence, the exact conditions to which the blocks were subjected could be readily determ- ined. Steam at at- mospheric pressure only was
. [Bulletins on forest pathology : from Bulletin , Washington, , 1913-1925]. Trees; Plant diseases. 30 S. DEPARTMENT OF AGRICULTURE. A steam box was constructed of cypress, equipped with thermome- ters, dew-point apparatus, and manometer and connected with the main which supplies steam to the laboratory greenhouse (figs. 15 and 16). By means of suitable reducing valves in the connecting pipes it was possible to control the steam pressure in the box; hence, the exact conditions to which the blocks were subjected could be readily determ- ined. Steam at at- mospheric pressure only was used. Previous to steam- ing, the blocks were again weighed. They were then close piled or strip- ped in groups of 25 in the steam box and steamed for differ- ent lengths of time. At the end of the steaming period, some of the lots were allowed to cool for a certain time and then reweighed. Others were weighed imme- diately. Nearly all were put in a small ventilated box in the open and allowed to air-dry for several weeks. Some, how- ever, were placed in a closed shed for four weeks, and still others were taken from the steam box, weighed, and placed directly in the tile chamber. Some lots were stripped; others were close piled. An interval of at least 3 inches was maintained between adjacent piles. After the preliminary seasoning mentioned above, a number of the blocks were returned to the tile chamber for incubation. This was done for the purpose of subjecting the blocks to the conditions exist- ing in box cars and poorly ventilated warehouses during warm and. Fig. 31.—Stacking sawed billets in an open shed. It will be observed that the billets at the extreme right are cross piled, while those in the center are close piled. The former method of piling insures a better ventila- tion of the stack, provided intervals of at least 1 inch are left between the adjacent billets of a course. In the case of the cross-piled billets shown here this pro- vision was not Please no
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