140 HORTICULTURE, FORESTRY, FLORICULTURE 



of brine, which, when sufficiently chilled, is circulated through refrig- 

 erating pipes in the cool chambers by means of pumps. The latter 

 method is known as the "brine" system. 



If a perfect insulation could be devised, a properly constructed 

 storage room, when once freed of its heat and sealed, could be held 

 at a uniform temperature indefinitely without further attention or 

 expenditure, but as no perfect nonconductor of heat has been found, 

 a continuation of the cooling process is necessary. In plants prop- 

 erly constructed and managed, equipped with duplicate machinery 

 to provide against break downs, it is now possible to maintain definite 

 temperatures for long periods with very slight variation, after the 

 initial heat of the stored product has been absorbed and removed. 

 It is this feature which gives these systems their special value in hold- 

 ing fruits and other perishable products. (Y. B. 1900.) 



Refrigeration. A factor of prime importance in the successful 

 shipping of fresh fruits long distances is quick and efficient refriger- 

 ation. The deciduous fruits are all shipped during warm weather 

 and must be kept cool while in transit. The ripening processes are 

 hastened when the fruit is picked. The development of molds also 

 goes on at a rapid rate while the fruit is warm. Reducing the tem- 

 perature retards the ripening and prevents the development of the 

 molds. The length of time that the fruit will remain in good condi- 

 tion depends upon the promptness and the thoroughness with which 

 it is cooled. 



Careful records made of many deciduous-fruit packages show 

 that the temperatures of the packed fruit during the greater part of 

 the season are extremely high. The range runs from 80 to over 100 

 F., and the average of all temperature records made is between 

 90 and 95 F. At such temperatures the fruit ripens very fast and 

 decay and deterioration are extremely rapid, especially if the fruit 

 has been roughly handled and injured to any great extent. 



Records made in refrigerator cars show that the rate of cooling 

 in the fruit package is very slow when the ice of the car is depended 

 upon both to reduce the temperature and to hold it low. It fre- 

 quently happens that several days elapse before the fruit is cooled 

 sufficiently to retard ripening and decay. This is the main reason 

 why the Pacific Coast fruits are picked so long before they have ac- 

 quired full quality. When they are not picked green, they become 

 over-ripe and soften before the ice of the car has a chance to reduce 

 the temperature below the danger point. 



Frequently a very distinct advantage may be gained by allowing 

 the fruit to remain open overnight and packing while it is cool in 

 the morning. More cooling can usually be obtained in this way than 

 in one or two days in the refrigerator cars after the fruit is packed, 

 especially where it is wrapped in paper. This is particularly true for 

 grapes, and many growers and packers take advantage of it. 



Precooling is usually done by mechanical means after the fruit 

 is packed, either in a warehouse or a cold-storage plant before load- 

 ing on the cars or after loading by forcing large volumes of very cold 

 air through the cars, thus reducing the temperature of the fruit much 



