CUEING TOBACCO. 227 



made that they can be opened and closed at will, because 

 these furnish an efficient means for controlling the hu- 

 midity, providing the weatherboarding of the building 

 is tight, as it should be. In ordinary weather, it is 

 probably better to use only the ventilating doors near 

 the ground, and the roof ventilators, leaving the higher 

 side doors closed, except as an emergency seems to require 

 special ventilation, and the control may be mainly exer- 

 cised by the roof ventilators, since by opening or closing 

 these more or less, the air, as it rises between the hanging 

 tobacco plants, may be compelled to rise more or less 

 rapidly, as desirable. But it should be remembered, 

 that when the external air is very moist, as in rainy 



V 



FIG. 63. TREE CRICKET (GEcanthus nlveus). 

 The plate at right is the male, viewed from above. At the left, female, side view. 



weather, this upward current of air will largely cease, 

 because the absorption of water from the tobacco will be 

 greatly checked. At such times, the temperature of the 

 air between the plants must be raised, to restore normal 

 absorption, and the only way to do this is to provide 

 artificial heat. Placing lighted lamps beneath the roof 

 ventilators will help to produce an upward current of 

 air, as was proved in our experiments, but this will not 

 avail to prevent pole burn if the air that enters the 

 building is already on the verge of saturation. 



The curing house should be enclosed in such a man- 

 ner that the amount of external air that enters it is un- 

 der control, and should be provided with some kind of 

 heating apparatus -that renders it possible to reduce the 

 humidity of the air in wet weather. To ascertain 



