BUREAU OF PLANT INDUSTRY. 151 



Twenty-three varieties had no decay, 9 varieties had less than one- 

 half of 1 per cent, and 4 varieties showed a loss of more than 5 

 per cent. 



Shrinkage weights were taken at harvest time (October 13), at the 

 end of the curing period 13 days later, and at intervals during the 

 storage period. Approximately one-half of the loss in weight takes 

 place during the curing period. The rate of shrinkage does not vary 

 much from month to month after the potatoes are cured. The aver- 

 age shrinkage for all varieties was 8.9 per cent on October 26, and 

 16.8 per cent on March 26. 



FLAX STRAW FOR PAPER MAKING. 



• 



During the year special effort was made to solve the problems in- 

 volved in using domestic flax straw for paper-making material. The 

 investigations have shown conclusively that the tonnage of flax 

 straw now estimated to be available can be greatly increased if pur- 

 chasers will buy in small lots and not insist (as is now the custom) 

 that straw for sale shall be baled. As a result of tests it has been 

 demonstrated that flax straw spread 20 inches thick will ret so as to 

 yield flax tow from which paper may be produced. By spreading 

 the straw thickly in this way savings in land rentals and labor cost 

 may be effected. 



Recently 130 tons of flax straw were retted successfully in Minne- 

 sota and will be used in connection with paper-making tests. A 

 complete experimental flax-tow machine is being installed at Dal- 

 ton, Mass., in order to tow this straw. This machine has a capac- 

 ity of about 5 tons of tow per day. Arrangements have been made 

 to determine whether this flax tow may be used in the production of 

 currency paper. Papers produced as a result of these experiments 

 will be submitted to the Bureau of Engraving and Printing of the 

 Treasury Department for examination in order to determine their 

 suitability for currency. Flax papers made in the Washington lab- 

 orator}^ of this project and submitted to the Bureau of Engraving and 

 Printing were reported to be suitable for such use, owing to their 

 wearing strength and printing quality. 



FRUIT-HANDLING AND STORAGE INVESTIGATIONS. 



The phases of the fruit and vegetable handling and storage inves- 

 tigations which have to do with commercial activities, including 

 transportation, cold-storage warehousing, and other phases that are 

 somewhat definitely of a marketing character, have been transferred 

 during the year to the Bureau of Markets and are now being con- 

 ducted there. In connection with the transfer of work, the members 

 of the staff of this office who were directly connected with the carry- 

 ing forward of these investigations were also transferred to that 

 bureau. Some phases of technical research have been developed, 

 however, which are fundamental in character and which have for 

 their object the determination of the factors affecting the storage life 

 of fruit and vegetables. This work includes within its scope not only 

 the response of fruits and vegetables as living organisms to different 

 storage conditions, but also the influence of cultural conditions upon 



