FRUIT STORAGE 109 
possibility of the escape of ammonia in the cold storage 
rooms. 
““Owing to the lower temperature and greater rapidity 
of the circulation of the ammonia gas, only about two- 
thirds the pipe surface is required to produce the same 
effect, as is necessary for brine circulation. 
“In the direct expansion system the refrigerating 
effect ceases upon the stoppage of the compressor. In 
small plants where this system is used it is not desired 
to operate the machinery but a portion of each day. 
One or more brine storage tanks can be placed in the 
cold storage room, in which a portion of the expansion 
coils are placed. The brine being cooled to a low tem- 
perature while the machine is in operation, this body 
of cold brine will help maintain the temperature during 
the time the machine is shut down. When brine storage 
tanks are used, they are placed overhead in the room to 
be cooled, when sufficient height permits, and arranged 
so as to create a proper circulation of air. The cost 
of installing a mechanical plant is much greater than for 
an ice system, but after once installed, especially for 
large houses, the operation would be much less. And 
in most places it is considered the most economical sys- 
tem to operate.”’ 
Ventilation—All fruit storage houses need to be 
constructed with a view to ventilation. This is neces- 
sary: (1) To remove the gases given off by the various 
products stored; (2) To remove the decay organisms 
that occasionally appear in storage rooms; and (3) To 
control, to some extent, the humidity required for the 
best keeping condition of the fruit. In the case of 
small ‘‘dug-outs’”’ or storage cellars on the farm, little 
