6 
BULLETIN 494, U. S. DEPARTMENT OF AGRICULTUE*:. 
scribed about 10 per cent per hour in the range from 70 to 90 per cent 
of relative humidity. In a condition below 50 per cent of relative 
hmnidity the humidifier acts more quickly, while at about 90 per cent 
it works very slowly ; in fact, it has been impossible in these experi- 
ments to raise the humidity in the curing rooms during ver}^ drv 
days much above 95 per cent with this apparatus. 
CONSTRUCTION OF THE HUMIDIFIER. 
The illustrations of the humidifier (figs. 1 and 2) show its general 
arrangement and its position on a truck, whereby it can be moved 
from place to place Avhen needed. The detailed structure of the 
humidifier is shown 
in figures 3, 4, 5, 6, 
and 7. The upper 
pan (1) is 36 inches 
long, 24 inches wide, 
and 6 inches deep. 
The lower pan (2) is 
of the same dimen- 
sions. The side (4) 
of the cloth chamber 
(3), which is open at 
both ends, is 36 inches 
long and 20 inches 
high, connecting the 
upper and lower 
pans. The raised slots 
(5) are 4 inches high 
and extend to within 
half an inch of either 
end of the upper pan, 
so that they are held 
firmly in position. 
Fig. 2. — Rear view of the humidifier, showing the arrange- Xlie UPPCr Cnds of 
ment of the electric fan in the hood. , • i i 
the raised slots are 
spread slightly, so as to allow the easy passage of the strips of 
cloth (6). The pans, sides, and other metal parts are made of 
galvanized steel of medium weight. The corners of the cloth 
chamber are strengthened, with angle iron. The upper edges of the ^ 
strips of Russian crash are drawn through the raised slots and 
allowed to drop down into the water in the upper pan, as shown 
in figure 7 at 7. The bottom edges of the cloths are bound with 
strips of sheet metal (8), so as to hold them in place. These bound 
edges of the cloth strips are held in the lower pan by means of spring 
clips or clamps (9) which are soldered to the bottom of the lower pan. 
The strips of cloth are 35 inches wide, so as to fit the raised slots, 
