FRUIT STORAGE 111 
lose weight by evaporation and will also shrivel. On 
the other hand, if there is too much moisture the fruit 
will be likely to decay. 
The amount of water vapor that can exist in any 
given space depends entirely upon the temperature. The 
higher the temperature the more moisture in a given 
space. When it reaches its maximum or point of satura- 
tion, it is then deposited on the fruit or packages and on 
the walls of the room and furnishes ideal conditions for 
the growth and spread of decay organisms. 
At one degree Fahrenheit the saturation point for 
air would be about 0.457 grains to one cubic foot. As 
the temperature rises, the holding capacity increases 
until, at 100 degrees, it will hold as high as 19.77 grains 
to one cubic foot of air space. At a temperature of 31 
or 32 degrees, the point at which most of the fruit is 
held in storage houses, the humidity would be about two 
grains to the cubic foot of air space. 
No very careful figures have ever been worked out 
for the best humidity for the different fruits, but in a 
general way they are carried at the same humidity as 
the percentage of water contained in the fruit. For 
example, apples will run from 80 to 86% water, and 
under such conditions the percentage of moisture in the 
air should be from 80 to 85 in the storage rooms. 
The percent of humidity represents only a relative 
condition. The exact weight of water in a cubic foot of 
air when the humidity is 85% and the temperature 31 
degrees, would be quite different from that for 70 de- 
grees. For calculating the exact quantity of water in 
a given space, a chart put out by the United States 
Weather Bureau should be secured. 
