FLORIDA STATE HORTICULTURAL SOCIETY 
73 
I shall give a few of the requirements 
of an efficient heater as I see them from 
the experience I have had and the inves¬ 
tigating I have done along this line. First, 
a large capacity heater is best. A heater 
should always hold enough oil to burn full 
capacity at least all night. In the past it 
has rarely been necessary to fire a grove 
during the day, but a heater should hold 
enough oil so that refilling at night would 
never be necessary under any circum¬ 
stances. It will always be necessary to have 
men out at night to fire them, but the re¬ 
filling should be done in the day time. 
Second, a gas-generating heater is best 
in my estimation. It is more economical 
in that you get more heat units out of the 
same amount of oil than you get from a 
heater which gives off a dense smoke. 
You burn the carbon instead of throwing 
it off in the air. There are probably 
many who will say that the smoke is 
worth as much as the fire. I do not agree 
with that. Smoke will keep off a frost; 
it will not keep off a freeze. A frost will 
not injure your trees nor fruit, and a 
freeze will. Smoke may save a vegetable 
patch or any plants that a frost will kill, 
but smoke will not raise the temperature. 
A gas-generating heater will throw off 
less soot and will discolor the fruit much 
less than one which makes smoke. This 
will be found to be a large item when 
it comes to cleaning up the fruit at ship¬ 
ping time. 
A practical heater should be as cheap 
as possible, consistent with the use of good 
materials. It should have few parts and 
few adjustments, because if it has too 
many parts it will be hard to put to¬ 
gether, the parts will get lost, and will 
get out of place, and be generally ineffi¬ 
cient. Too many adjustments will com¬ 
plicate it beyond the ability of the labor 
available to operate it. Drafts or damp¬ 
ers are an absolute necessity. There are 
times when it will be necessary to fire 
up early in the night with the thermome¬ 
ters just at the danger point. It may stay 
there until morning, or it may go either 
way—up or down. If it goes down sud¬ 
denly, as it frequently does, it will be 
necessary to open the heaters up and open 
them quick. They should be so arranged 
that the drafts can be quickly and accu¬ 
rately set by our ordinary labor. It is 
not economical to burn fuel enough to 
raise the temperature io degrees when 
five is all that is needed, as oil is too' ex¬ 
pensive here to raise and keep the tem¬ 
perature at 35 when 30 is high enough. 
The weather bureau can give you in¬ 
formation as to where to obtain wet and 
dry bulb thermometers, and how to use 
them to determine the dew-point, which 
will help you to determine how low you 
dare let the temperature go. A heater 
should be made of good material in order 
to withstand the damp climate here as 
much as possible. Light guage steel will 
rust out in one year even after being 
dipped in crude oil. The heavier guage 
a steel is the better, even though it in¬ 
creases the cost of the heater. 
I shall now try to give you an idea of 
the practical application of heaters as 
we have used them, and then a table of 
costs. Some four years ago we put in 
2,500 three-gallon heaters with twenty-six 
6oo-gallon tanks through the grove for 
reserve supply of oil; also a concrete cis¬ 
tern, holding 25,000 gallons. We have 
