270 HORTICULTURE FOR SCHOOLS 



carrying of fruits for any considerable length of time. More- 

 over, a high consumption of ice is needed to offset the un- 

 avoidable heat leakage. 



When the fruit is packed and loaded into the car while 

 warm, there is a very considerable variation in the temper- 

 ature conditions in different parts of the carload. The 

 warmer air rises to the top of the car, and accumulates in a 

 layer which extends far enough down to affect the upper tiers 

 of packages. It is cool, of course, but not to the same degree 

 as the air below. For this reason, perishable produce cannot 

 be loaded to the full height of the car. Frequently in the 

 case of quick ripening fruits, the packages on the upper tiers 

 arrive in market with considerable deterioration due to over- 

 ripeness and decay, while those in the bottom tiers arrive in 

 sound condition. 



The limitations of refrigeration have led to attempts to 

 cool the fruit, or the air in the car or both, before the train 

 starts on its way. Experiments in precooling were conducted 

 by the United States Department of Agriculture, with results 

 that seemed very satisfactory, and this process is now being 

 practiced with oranges. Attempts to precool other fruits have 

 not proved as satisfactory, but it is probable that in the future 

 practical and inexpensive methods will be devised. 



385. Storage consists in placing products under favorable 

 conditions for continuing their life activity slowly and thus 

 prolonging their life span. Storage may be carried on accord- 

 ing to either of two ways : 



(1) Cold storage consists in holding compartments or 

 rooms cool by special means, to the lowest possible tempera- 

 ture that will keep the fruit in good condition. This tempera- 

 ture is usually 32 degrees. 



(2) Common storage, sometimes called dry storage, consists 

 of storing in special rooms or plants; the process depends on 

 ventilation to cool the fruit and hold it in good condition for 

 a longer period than the normal season. There is no artificial 



