158 ANNUAL EEPOKTS OF DEPARTMENT OF AGRICULTTJRE. 



The freezing investigations have clearly demonstrated that a little 

 more insulation, with the provision of floor racks, vs^ill eliminate over 

 90 per cent of the freezing now occurring in the shipment of citrus 

 fruits from California. This freezing protection is not only related 

 to insulation and floor racks, but also to heavier loading. In fact, 

 the refrigerator-car investigations, both as regards efficiency and 

 ecofiomy of refrigeration and the protection of perishables against 

 freezing during severe weather, indicate that whatever improve- 

 ments are made to increase the efficiency and economy of refrig- 

 eration likewise make for the more adequate protection of perish- 

 ables against freezing. While some investigation is being made of 

 heater equipment, the investigations indicate that freezing protec- 

 tion is fundamentally related to the insulation and construction of 

 the refrigerator car, supplemented with proper loading. They also 

 indicate that, as regards economy and efficiency the year round, 

 it is going to be a more fundamentally sound and economical 

 proposition to provide protection for perishables against freezing 

 through proper car construction and the provision of sufficient in- 

 sulation than by the installation of expensive and uncertain heater 

 equipment that is useful only during the freezing season. 



These investigations have been conducted in close cooperation with 

 similar investigations with regard to poultry and fish in the Bureau 

 of Chemistry. 



NORTHWEST APPLE STORAGE. 



Several new phases of the general fruit-storage problem were de- 

 veloped in the investigations conducted during the past year. The 

 relation between keeping quality in the storage of apples and meth- 

 ods of handling in the harvesting, grading, and packing of the 

 fruit, the stage of maturity at which fruit for storage should be 

 harA'ested, and the importance of prompt cooling in the storage of 

 fruit were subjects of further investigation in the Northwest. The 

 results indicated particularly that fruit intended for storage in air- 

 cooled warehouses requires an equal or even a greater degree of care 

 in handling in all the operations of preparing the fruit for market 

 than has been found to apply to fruit held in cold storage. 



Aside from the problems connected with methods of handling, the 

 results of the apple-storage investigations have clearly shown that 

 the two most vital problems relating to the successful storage of 

 apples in the Northwest are the proper design and construction of 

 common storage warehouses and the efficient management of these air- 

 cooled storage houses. The work emphasized especially the import- 

 ance of improvements in the methods of management of air-cooled 

 storage houses. A careful investigation of the efficiency of the com- 

 mon storage houses in use indicated that the most important features 

 in the construction of these warehouses are adequate insulation and 

 more efficient means of providing ample ventilation to insure maxi- 

 mum cooling at night by natural air circulation. The data secured 

 clearly show that the rate of cooling of fruit immediately after 

 storage is almost wholly dependent upon the methods of storage and 

 the arrangement and size of ventilators provided, and in this respect 

 there is a general need for improvement in the means provided to 

 insure the adequate and prompt initial cooling of the fruit. In a com- 



