1914] | HASSELBRING—EFFECT OF SHADING 265 
TABLE I1I—Continued 
MEAN TEMPERATURE MEAN TEMPERATURE 
FoR 24 HOURS ENDING (FAHRENHEIT) (CENTIGRADE) 
AT 4 P.M. DIFFERENCE 
Open Shade Open Shade 
<a ee a 
January Bes. 71.24 70.24 —1.00 21.80 21.24 
¥ Ble 68.05 68.57 -+o.52 20.03 20.32 
: 2 eae 65.98 66.87 +0.89 18.88 19.37 
eck 66.35 66.22 —0.13 19.08 19.01 
6,.... 62.58 64.40 +1.82 16.99 18.00 
cy... 63.13 64.10 +0.97 17.29 17.83 
ae 60.20 60.86 +o0.66 15.67 16.03 
Within a cheese-cloth tent was 1-3° F. higher than that outside. It 
1s possible that the climatic conditions in these two regions are 
sufficiently different to account for the apparently different effects 
of the cheese-cloth, but it should be stated that StewART obtained 
his average daily temperature from the maximum and minimum 
temperatures of each day, a method which does not give the true 
average temperature. It is evident from the data of table III that 
under the climatic conditions prevailing in Western Cuba during 
the months of December and January the cheese-cloth tents used 
for shading tobacco in that region show very little tendency to 
retain heat. 
Relative humidity 
The relative humidity in the two stations was recorded by means 
of Draper hygrometers. These instruments, like the thermographs, 
d been kept under observation for several weeks previous to the 
beginning of the experiments, and during that time had been 
adjusted to correspond through the lower part of their range with 
4 sling psychrometer. Since the range of these instruments was 
hot adjustable, it was not possible to make them correspond with 
© Psychrometer readings through the whole range of the scale. 
At might, when the sling psychrometer regularly showed a relative 
humidity of 100 per cent, the hygrometers still showed a deficit of 
4-5 per cent. The recording instruments, however, agreed with 
each other throughout the range of the movement of the pens. 
Each week during the course of the experiment the instruments 
Were compared by being placed side by side for one hour. They 
