80 BOARD OF AGRICULTURE. [Pub. Doc. 



as soon as it becomes too moist. In other words, the air must 

 be heated before it comes in contact with the tobacco, and it 

 must be removed as soon as it becomes moist. 



If we raise the temperature 20°, we double the cajiacitvjfor 

 holding moisture, and if the temperature in the barn can be 

 kept 15° to 20° higher than that of the outside air, with a 

 reasonable amount of ventilation, there is no danger of pole 

 sweat, no matter how wet the outside weather may be. Warm 

 air is, of course, lighter than cold air, and, surprising as it 

 may seem, moist air is lighter than dry air at the same tem- 

 perature. For these reasons the natural course is to admit the 

 outside air at the bottom of the barn, heat it to the proper tem- 

 perature and allow it to move upward through the tobacco. 

 Sufficient heat must be applied to drive the air through the 

 tobacco fast enough to prevent its becoming chilled, otherwise 

 it will stagnate before reaching the top of the barn. Too little 

 heat is worse than none, for it simply drives the moisture 

 from the lower into the upper portions of the tobacco. It is 

 also necessary to provide some means of escape for the warm 

 moist air when it reaches the top of the barn. If the roof is 

 not tight there may be sufficient natural ventilation, but with a 

 very tight roof, a ventilator is needed along the peak of the 

 building. 



The next question is as to the best means of applying the 

 heat. Open charcoal fires have been used to some extent and 

 with sticcess, but the method is laborious and expensive. For 

 best residts the heat must be well distributed, so that a large 

 number of small fires is better than a few larger ones. The 

 charcoal burns out rapidly, so that the fires require close 

 attention. We have been endeavoring for the past three or 

 four years to work out a simple and cheap method of heating 

 based on the use of flues and heaters or furnaces, using wood 

 as fuel, and I feel confident that we will soon be able to an- 

 nounce a satisfactory process. A system of this kind will 

 insure a more even distribtition of the heat, and the amount 

 of heat can be more easily controlled. I believe that artificial 

 heat will be used more and more as its advantages are more 

 fidly recognized, especially in curing picked tobacco. 



