IRRIGATION IN FLORIDA. 35 
to 300 acres in the western part of the State, the largest acreage 
being in Polk and Hillsboro Counties. 
Spray irrigation has been found to be of considerable value as a 
protection against frost in the southern part of the State. Some 
farmers claim they have saved their entire crop from frost injury by 
their spray systems. 
The installation of a complete irrigation system covering several 
acres by means of these nozzles does not differ greatly from that of 
the overhead-pipe system, the pumping outfit and main line being 
similar in both. The lateral lines of the overhead-pipe system must 
be elevated above the ground surface, as every nozzle is turned on at 
once. The laterals of the other systems usually are placed under- 
ground, while the nozzles are elevated by means of upright pipes 
connected to the underground lines. In the overhead-pipe system 
the lateral lines are placed perpendicular to the main, the size of 
the pipe increasing toward the main as the length of the lateral 
line is increased. The circular nozzles are placed close enough 
together so that water from one will overlap the space watered by its 
neighbor. The parallel laterals also must be placed close enough to- 
gether for the irrigated spaces to meet. It is evident that this dis- 
tance will vary with the radius of distribution of the nozzle. The 
nozzles of alternate laterals usually are placed opposite, so that the 
circular areas covered by all the nozzles will fit into each other. 
It is not necessary to go into details of the design of pump and 
engine, as it will be seen that if the capacity of each nozzle is known 
the problem differs in no way from that of the overhead-pipe 
systems. The stationary-nozzle types usually require considerably 
more water than the other system, and this means larger pipe lines if 
the same amount of land is to be irrigated at one time. Each lateral 
is fitted with a cut-off, as in the case of the overhead-pipe system, so 
that any amount of land required may be watered simultaneously, 
provided the main and the pumping outfit are of proper size and ca- 
pacity. The pressure required is about the same for all the overhead 
systems. 
Advocates of the whirling-nozzle type claim that their systems are 
automatic and need no turning by hand. The advocates of over- 
head-pipe systems claim that this difficulty can be overcome easily by 
installing an automatic turning machine, and that the turning of the 
lines by hand is very simple and requires little time away from other 
work. The small aperture in the overhead-pipe nozzle may cause 
trouble by becoming clogged with small pieces of sand or fiber. This 
does not happen usually with some rotation nozzles, but may stop 
others. Good screens or filters will stop this trouble to a large extent. 
The smaller nozzle may be cleaned with a pin and the rotating nozzles 
