REFRIGERATION OF DRESSED POULTRY IX TRANSIT. 
23 
and thorough mixing of the salt, which produces very low tempera- 
tures. These four, together with the simple box arrangement 
shown in figure 12, are the types of ice bunkers now in common use. 
Most of the others are minor modifications of these five. 
The various types of cars studied show that there is a wider diver- 
gence in the construction of the ice bunkers than in any other single 
refrigerator-car essential. This is undoubtedly due to a recognition 
on the part of the car builder of the importance of this fitting in the 
performance of the car, and the varying forms of the bunker repre- 
sent the endeavors of 
the builders to meet 
modern requirements 
in the transporta- 
tion of refrigerated 
ice bunker in a refriger- 
a place analogous to that 
erating machinery in a 
stationary plant. It must chill every 
inch of working space hi the compart- 
ment depending upon it. It would 
seem, from the observations made on 
the types of cars described, that the aim 
of the builder must be to induce a circu- 
lation of air which will convey the lower 
temperatures at the bunker ends to the 
center of the car. To do this efficiently 
the bunker must be assisted by proper 
insulation on the surfaces of the car. 
Correlating the construction of the 
bunkers with the table 
of efficiencies of the 
four types of cars, two 
essential principles for 
the production of low 
temperatures stand out prominently. First, the bunker must per- 
mit of the ice being finely crushed and evenly mixed with the salt; 
and, second, there must be a free admittance of the warm air of 
the car at the top of the bunker and a free exit of the cold air at 
the bottom. Such requirements are apparently met most suc- 
cessfully by the tank on the one hand and the wire basket on the 
other. In this case simplicity of construction has been compatible 
with efficiency. 
Various attempts have been made to use overhead ice bunkers 
and, in a few instances, brine pipes for circulation have been tried, 
but in most cases the objectionable features were so numerous that 
Siphon bunker used in type A car 
