10 BULLETIN 1367, U. S. DEPARTMENT OF AGRICULTURE 
ing through a long conduit. The mean temperature of the ground 
2 feet below the ‘surface in Florida during the early fall, when 
much of the coloring is done, is somewhat lower than the air tem- 
perature. Soil also conducts heat more readily than air. This 
explains, then, the fact, as shown in the table, that passing the gas 
through a buried pipe reduces the temperature more than passing 
it through a pipe exposed to the air. Cooling the QE pipe 
by spraying it on the outside with water is of some value, but does 
not increase the relative humidity as much as adding water di- 
rectly to the gas in the fan intake or passing the gas over the water 
in the pipe. ~The results of dropping water into the intake pipe 
are shown in Figure 4. There is no doubt, however, that the gas 
can be cooled down appreciably by passing it through long con- 
duits either under the ground or in the shade. It is “also obvious © 
that by adding water, further cooling can be obtained and the rela- 
tive humidity increased. 
TABLE 1—HLHffect of forcing gas through pipe below and above ground and of 
adding water on the temperature and relative humidity of the coloring room 
with exhaust fans delivering about 1,700 cubic feet per minute 
: Relative hu- 
Temperature (°F.) midity 
(per cent) 
Equipment 
Out- | Enter- | Out- | Enter- ee oe Out- 
side ing going ing | going 
} 
35 feet of galvanized rain spouting 6 inches in diameter 2 feet | 
below ground; no water added__._-_-._-_...--.-------__----- 71 92 | 84 | 40 | 56 
50 feet of iron gas pipe 6 inches in diameter 3 feet below ground; iad o ee | Sh | 2 
100 drops of water added per minute to gas at entrance__-_-_---|]~"~~ 88 o1| - 85 40 75 
if Sz] 100 eee ee ean 92 
= 77 103 | 90 43 
100 feet same____-_----------------+-------+---+-22-2--2-------- h ga] 100| 87 | 40 85 
74 101 | 84 42 86 
85 95 85 | 61 81 
90 feet of galvanized rain spouting 6 inches in diameter above | = a ae oe a 
ground but under the floor; no water; temperature of air sur- | 82 92 82 37 | 80 
ROUEN pipe (LOAN eS s 2. ae ere oe eccnee | 82 94 | 82 49 | 69 
76 95 | 73 39 78 
30 feet of galvanized rain spouting 6 inches in diameter above | { 88 97 | 98 28 61 
ground; water added at entering end__________---_-__-______- 75 85 86 } 40 Se 
85 101; 101 25 | 
Samevexcept NO) water, addede—--. oe eens eee { 30 90 | 89 | 25 25 
20 feet, same; 100 drops of water added per minute at entrance _| 85 106 95 } 46 69 
SS ECE CEE GME SRT 2 A ee eee eee: A rl ee ere | 85 106 | 93 46 73 
HUMCAL SAIN G2 wise ens Seen te dS "a ne) SRI, | 85 106 | 88 46 85 
60 feet, SSERTTA CLS Ree a Se Ee eB Bg ER 85 106 | 88 | 46 85 
76 80; 81 Btiae 72 
77 83 81 66 80 
: , : : an. 82 85 83 63 76 
45 feet of galvanized rain spouting 6 inches in diameter inside | 70 86 | 81 63 76 
building and above the coloring rooms; 100 drops of water | 81 88 | 82 | 61 80 
added perminute at entennerends. = -oeee eee 78 84 | 79 | 66 79 
| 72 78 77 | 79 87 
76 81 “4 80 83 
75 82 7 80 83 
Raia iis te Tea St 
Cooling the gas by refrigeration is another method used to some 
extent in Florida. One plant is equipped with mechanical re- 
frigeration, passing the gas over direct expansion coils on its way 
from the oenerating chamber to the coloring room. Other plants 
pass the gas over blocks of ice or place ice in the coloring rooms. 
