REPORT OF COMMITTEE ON PUBLICATION 295 



current flows outward along the floor of the car, and absorbs heat from the 

 fruit packages. As it warms it rises to the top of the car and circulates back 

 to the ice bunkers where it is again cooled by the ice. The rapidity of the 

 circulation of the air currents within the car is thus greatest at the beginning 

 when the difference in temperature of the car within the bunker and the car 

 body is greatest. As the fruit cools this temperature difference becomes less, 

 and the movement of the air currents becomes more sluggish. The tem- 

 perature of the air is always considerably (5 to 10) higher at the top of 

 the load, and the fruit on the top tiers of the load is thus subjected to a 

 considerably higher temperature while en route than the fruit on or near 

 the floor. 



The fruit from the top tiers frequently arrives in market showing con- 

 siderable deterioration while that from the bottom tiers may be in sound 

 condition. For this reason, growers prefer to have their fruit loaded on the 

 bottom layers or tiers, and shipping companies have difficulty at times in 

 satisfying all their patrons. Obviously, all can not have their crates placed 

 in the lower part of the load. When the investigations of the decay in grapes 

 were begun, some objections were made by shipping companies against a 

 study of the behavior of fruit loaded on the bottom and on the top tiers, on 

 the ground that the results might increase their difficulty in satisfying the 

 owners of fruit which had to be loaded on the top layers. Instead of in- 

 creasing the difficulty of shippers in this respect, the results are really 

 beneficial in that they show that the difference in temperature is not the 

 only factor governing the difference in the condition of the fruit. This is 

 conclusively shown when the results are analyzed. Table IV shows the 

 average percentages of decay found in crates of Tokay grapes loaded on the 

 bottom and top tiers of the loads in all the shipments made during an entire 

 shipping season. The "Commercially Handled" lots were those obtained from 

 ordinary shipments, the "Carefully Handled" were picked and packed by the 

 Department investigators. 



TABLE IV. Average percentages of decay in commercially handled and 

 carefully handled Tokay grapes, packed in crates, loaded on the bottom 

 and top tiers in refrigerator cars, and shipped to New York City. 



Carefully Handled Commercially Handled 



Bottom Top Bottom Top 



Tier Tier Tier Tier 



% Decay % Decay % Decay % Decay 



On arrival at New York 0.6 1.4 3.6 8.4 



Three days after arrival 1.8 _2.2 7.2 11.1 



Five days after arrival 3.5 6.7 12.0 19.2 



Seven days after arrival 5.0 12.5 15.2 19.8 



The figures shown in Table IV are presented to establish the general 

 principle that the type of handling given the fruit in preparing it for ship- 

 ment ha^; an important influence upon its behavior under the varying condi- 

 tions of temperature within a refrigerator car. While there is higher decay 

 on the top tier of the load both in the fruit given ordinary commercial hand- 

 ling and that handled with special care, the results obtained from the ex- 

 perimental shipments show that the difference between top- and bottom-tier 



