32 BULLETIN 16, U. 8. DEPARTMENT OF AGRICULTURE. 
it is highly desirable that the barn be so arranged as to be fully 
and freely ventilated, so that it may be possible to steadily remove 
the warm, moisture-laden air as it becomes saturated. 
In drying out an ordinary 16-foot or 18-foot barn, holding say 500 
sticks of cut tobacco, about 5,000 pounds of moisture (water) must 
be removed. The movement of the air through ventilation is the 
only means of getting rid of this large amount of moisture. Raising 
the temperature of the air increases its capacity to absorb moisture 
and creates a draft, provided means are afforded in the construction 
of the barn for letting out the air rapidly at the top and for letting 
it in at the bottom. For the outlet at the top a short lever device at 
each end of the peak for raising the ridgeboard by means of wires 
Fie. 11.—A good type of flue-curing tobacco barn, showing the ridgepole ventilator 
raised. The mouth of one of the bottom air inlets is seen just under the open door. 
reaching to the ground, as shown in figure 11, is a handy and simple 
arrangement. The slit left open when the ridgeboard is raised should 
be about 5 inches wide. To admit air at the bottom there is always 
the door, which can be partially opened at will; but this method 
gives an excess of air immediately in front of and over the door. For 
an even distribution of the air in all parts of the barn, sewer pipes, 
about the 4-inch size, set in the wall at appropriate places, will make 
a good arrangement for the bottom ventilation. The pipes should 
be set in the wall close to the ground, but just above it on the out- 
side; they should dip just below the ground on the inside, the open- 
ings of the different pipes being, respectively, under and near the 
end and at the middle of each length of flue, including the returns. 
Each air pipe should be fitted on the outside with a suitable wooden 
