42 
FLORIDA STATE HORTICULTURAL SOCIETY 
do not have the same degree of moisture 
we have here. 
The point of my whole talk is, to im¬ 
press upon you the importance of thor¬ 
oughly drying your fruit before packing 
it. Just apply the commonest law of phys¬ 
ics. T ori have a cool orange in a warm 
room; it will attract moisture just as long 
as it is cooler than the atmosphere. Now, 
then, if we pre-cool our fruit to the dew 
point, we invite moisture. If we put it 
up dry and put ice in the cars with it, we 
cool the fruit down to such a point that 
it will attract moisture from the warmer 
air outside and will “sweat.” If we dry 
our fruit instead of pre-cooling it, we 
will not need ice. In fact, the car that 
we shipped under ice this season, showed 
more decay than any other car, shipped 
Avithout ice. 
Failure to dry fruit properly in cold, 
damp or foggy weather by the methods 
generally in vogue: On suggestion of O. 
YV. Sadler, Jr., as I have said, I took up 
the question of the efficiency of heat in 
evaporatng water and the necessary ra¬ 
pidity of movement of the heated air in 
drying fruit, with the University of 
Gainesville. 
J. R. Benton, Professor of Physics 
and Electrical Engineering, made the fol¬ 
lowing reply: “It is not difficult to com¬ 
pute how much moisture could be taken 
up by air at any specified temperature. 
• he best effect would probably be pro¬ 
duced by having the air as hot as the 
fruit would stand. 
As an illustration of the story of fig¬ 
ures that could be obtained let it be sup¬ 
posed that you start with air at 68 de¬ 
grees F, completely saturated with mois¬ 
ture; heat this air to 200 degrees F., then 
let it pass over the fruit and leave the 
fruit at 86 degrees F. Then one cubic 
foot of air should carry with it .36 
grains of water. Just how much mois¬ 
ture sticks to one orange, I do not know. 
As a pure guess, I should say about one 
* 
gram (15 grains) , so that approximately 
three cubic feet of air under the condi¬ 
tions specified would be required for 
each orange. The amount of heat nec¬ 
essary to warm the air as specified above 
amounts to 554 calories for each cubic 
foot, and this would require the burning 
of .2 of a gram of wood, so that one 
pound of wood should be enough to heat 
about 2,000 cubic feet of air if no heat 
was lost, and should probably be sufficient 
to dry about 700 oranges. 
(These computations make no allow¬ 
ance for practical difficulties and imper¬ 
fections, but represent the best that can 
be obtainable under ideal conditions.” 
By what means, then, shall we get the 
greatest efficiency in thoroughly drying 
fruit by heat? 
In my opinion, there can be no more 
efficient method than by steam confined 
in pipes, run close under the rolls carry¬ 
ing the fruit in the drying box. In this 
way, the heat would be absolutely under 
control as to quantity and temperature. 
A little experimenting in each plant or 
packing house would soon determine the 
temperature required for the capacity and 
speed of the drying box. When this is 
determined, a thermostat would control 
that amount automatically, whether the 
drying rack traveled slow or fast, or not 
