564 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Experiments with reference to the handling and storage of Cali- 

 fornia table grapes confirmed tlie results of the tests made during- 

 the previous season, and showed that spruce sawdust is a suitable 

 and commercially satisfactory packing material. More than 80 cars 

 of Emperor grapes packed in spruce were shipped in the fall of 1919. 



For several years demonstrations have been made in the Pacific 

 Northwest to point out proper methods of constructing and operat- 

 ing apple storage houses. With the rapidly increasing production 

 of apples in this region tiiere has been an acute shortage of refrig- 

 erator cars to move the crop from producing sections, and there has 

 been an insistent demand for information concerning the proper 

 design, insulation, and ventilation of both common storage and cold 

 storage warehouses. During the present season assistance has been 

 given growers and shippers in providing additional common storage 

 houses for 1,220 carloads of apples and cold storage houses of 800 

 carloads capacity. Effective work was done by assisting sweet potatO' 

 growers to build more than 500 new storage houses having an aver- 

 age capacity of about 2,500 bushels. The combined capacity of 

 efficient storage houses for sweet potatoes built during the last three 

 years in accordance with recommendations of the department^ 

 amounts to approximately 5,000,000 bushels. Data were secured 

 regarding the temperature and humidity which should be maintained 

 in storage houses for the most effective curing and storage of sweet 

 potatoes. 



Additional data have been secured concerning the freezing points 

 of fruits and vegetables. The effect of low temperature on sweet 

 potatoes, tomatoes, and other fruits and vegetables was studied to 

 determine the proper methods of handling products injured by 

 chilling or freezing in order that they may be utilized as food. 

 Through this work it has been possible to obtain fundamental in- 

 formation regarding suitable temperatures for the cold storage of 

 fruits and vegetables. It was demonstrated that by holding Cali- 

 fornia table grapes at 28° to 30° F. instead of 32° (the ordinary 

 temperature used in commercial storage), the storage period may be 

 lengthened by at least 30 days, thereby materially extending the 

 marketing season. Experiments are being carried on to determine 

 the safe minimum storage temperature for apples, lettuce, celery, 

 and other fruits and vegetables. 



Investigations concerning the preservation of fruits and vegetables 

 by freezing storage were continued. The factors affecting the keep- 

 ing of these products and the influence of temperatures ranging from 

 20° F. to —5° F. on the quality and condition of frozen berries, 

 plums, cherries, beans, sweet corn, and other fruits and vegetables 

 were studied. A more extensive utilization of freezing storage seems 

 entirely practicable and desirable in many of the larger market 

 centers where surplus stocks of highly perishable fruits and vege- 

 tables are available. 



COMPLETION OF THE WORK OF THE DOMESTIC WOOL SECTION 

 OF THE WAR INDUSTRIES BOARD. 



For the completion of the work of the Wool Division of the War 

 Industries Board the sum of $35,000 was appropriated for the fiscal 

 year 1920. This work was directed by Mr. Wells A. Sherman. 



