12 BULLETIN 475^ V. S. DEPARTMENT OF AGEICULTUEE. 
usually so open at the bottom that it is not necessary to make special 
provision for fresh air. Where the drying room is heated from 
below fresh air can be admitted through dampers or ventilators in 
the jacket surrounding the stove. Vents to maintain circulation 
should also be provided in the roof of the drying room. 
Though they are usually the best that are practicable, these methods 
of ventilation are necessarily crude and wasteful. As the air cools 
and absorbs moisture it becomes heavier and sinks to the floor. Vents 
in the roof carry off much of the hot, dry, light air which should be 
retained. A certain amount of heavy, moist air is, however, carried 
out with the current, and the circulation of air, so essential to drying ^ 
the cones, is maintained. 
An improved method removes the saturated air directly from the 
floor by pipe ventilators extending from the floor through the roof. 
In one kihi fresh air is admitted directly under a small box stove 
with a heating drum placed near the center of the room. As this air 
becomes heated it rises to the ceiling, where it spreads to the side 
walls, and, cooling slightly , descends in a steady stream over the cones. 
The trays thus catch the descending current of hot air, which flows 
over them. They are slightly tilted toward the center of the room, 
so that as the air cools and absorbs moisture from the cones it runs 
off the lower edge of the trays like water from a roof. The saturated 
air is sucked up by pipe ventilators having inlets at the floor level and 
passing through the roof. 
WETTING CONES. 
Wetting cones before drying apparently does more harm than good 
with any species except lodgepole pine. Lodgepole-pine cones dipped 
in very hot water for not over one minute have, in some cases, been 
found to open more readily and to give a higher yield than un- 
moistened cones. This treatment, however, should be applied only 
to very tight cones and should not be of sufficient duration to add 
appreciably to their water content. Its only advantage is that it 
loosens the sealed tips of the cone scales. Experiments have also 
shown that live steam applied under a pressure of one-half pound 
for 30 seconds assists in opening cones without impairing the fertility 
of the seed. Such treatment, however, is possible only at fully 
equipped extracting plants. 
Even with lodgepole pine a preliminary wetting is not essential, 
and good results are obtained without it. Continued soaking of 
cones has almost uniformly lessened the ease of extraction and in- 
jured the seed. As a general rule, the cones should be as dry as 
possible before they are put into the kiln. Preliminary drying in 
the open or in well-ventilated storerooms will hasten opening after 
artificial heat is applied. 
