8 BULLETIN 1367, U. S. DEPARTMENT OF AGRICULTURE 
When the weather is cold, as it is at times during the winter, it 
may be necessary to heat the coloring room in order to have the 
proper temperature. This can be done with small kerosene heaters 
or by heating the air in the gas-generating room by removing the 
plates from some of the burners and using them to heat the gas de- 
livered to the coloring rooms. 
IMPORTANCE OF COLORING QUICKLY 
It is obvious that it is desirable to color fruit as rapidly as can be 
done without injury to its appearance or its dessert or keeping 
quality. If it is colored in 24 to 36 hours, a much smaller plant can 
be used than when it is kept in the coloring room from 48 to 72 hours, 
and the overhead expense will thus be greatly lessened. Another 
reason for making the coloring process as short as possible is the 
fact that much of the citrus fruit in Florida is affected with stem- 
end rot caused either by Diplodia natalensis or Phomopsis citri, 
which, according to Fulton, Winston, and Bowman,® will develop 
at temperatures above 45° or 55° F. If the fruit is colored slowly 
at temperatures from 60° to 75° there is much more danger of 
its breaking down from these diseases than if it is colored quickly 
at higher temperatures, then packed, cooled, and shipped to market 
and consumed before these rots have an opportunity to develop. It 
is, of course, evident that some method of quick cooling after the 
fruit has been colored is advisable with such fruit as has shown a 
marked tendency to break down from these diseases. 
METHODS OF REGULATING TEMPERATURES IN COLORING ROOMS 
The importance of a fairly even temperature in the coloring room 
if fruit is to be colored quickly and evenly was recognized early in 
this work, and a number of different methods of controlling tempera- 
tures were tested. 
INSULATION OF COLORING ROOMS 
One of the methods of partially overcoming the effect of changes 
of outside temperatures on the coloring rooms is insulating the 
room. ‘This insulation need not be expensive, but may consist of 
paper and sawdust or mill shavings, which are relatively cheap and 
easily obtained in Florida. Double walls with paper—that is, board- 
ing on both the outside and inside of the studding with paper next to 
the studding—has some insulating value, as it provides air spaces 
in the wall and lowers the heat leakage through it. If these air 
spaces, 4 to 6 inches in thickness, are filled with dry sawdust or mill 
shavings, the insulation will be much more efficient, and it will be 
much easier to keep the coloring room at an even temperature. 
COOLING AND HUMIDIFYING THE COLORING ROOM 
At times the temperature in Florida may be too low for rapid 
coloring, but it is more likely to be too high in the coloring room, 
so that care not to introduce too much heat with the gas is of fore- 
most importance. One precaution against overheating the coloring 
5 J. R. Winston, H. R. Fulton, and J. J. Bowman. Commercial controi of citrus stem- 
end rot. U. S. Dept. Agr. Cire. 293, 10 pp., illus. 1923. : 
