APPLICATION OF REFRIGEKATION TO HANDLING OF MILK. 
21 
mon salt. The solution should not be stronger than the temperature 
to be maintained requires, as the specific heat of brine decreases as 
the strength of the solution increases. A part of the pipe coils are 
placed in the tank containing the mixture of salt and ice, and a 
part are led down into the cooling room below. The coils of pipe 
that are in the cooling room absorb heat from the stored goods 
Fig. 8. — Gravity brine system. 
and those in the tank give up heat to the freezing mixture of salt 
and ice. 
The operation of this system is as follows : The brine in that part 
of the pipe circuit in the tank becomes heavier as it is cooled and 
flows down into the storage room, forcing the warmer and there- 
fore lighter brine up into the coils in the tank. The heat ab- 
sorbed in the storage room is transferred to the mixture in the 
tank by the natural circulation of the medium. This system is to a 
certain extent automatic in its operation, as an abnormal rise in 
temperature of the storage compartment from any cause increases 
the velocity of the brine circulation and therefore increases the re- 
