TRANSPORTATION 143 
houses of each of the local exchanges and draw fruit 
from the area from which the exchange operates. 
The fruit is cooled down as soon as it is brought in 
from the orchard. After being sufficiently cooled, it is 
stored in a cold room or loaded directly into the cars and 
sent off. Before the inauguration of the pre-cooling 
plants, cars of fruit moving north or east during the 
hot season would need to be iced every four days. In 
some cases, every three days. This would mean a stop 
of from two to six hours at certain icing stations along 
the road to refill the bunkers of the cars. As the rail- 
road companies always charge extra for this it adds very 
materially to cost of transportation of the fruit. 
Pre-cooling plants, for the most part, cool the fruit 
down sufficiently before starting so that the initial icing 
is sufficient to carry the fruit across the continent, thus 
making a saving both in expense and time in transit. 
In some eases pre-cooling is working so satisfactorily that 
fruit can be shipped across the continent without any 
ice in the bunkers. 
In the car system for pre-cooling fruit sufficient cool- 
ing space and track surface is necessary to accommodate 
a full train of fruit consisting of about 32 cars. From 
four to five hours are required to cool down the fruit 
in these cars to a temperature of 45 degrees which is 
considered desirable before starting them on their long 
journey. The method of producing the cold is similar 
to the ammonia pressure system referred to in connec- - 
tion with the large public cold storage houses. One of 
the largest of these plants in California contains over 
35 miles of pipe coils through which brine with a tem- 
perature below zero is circulated, The air surrounding 
