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BULLETIN 322, TJ. S. DEPARTMENT OF AGRICULTURE. 



able item where the material must be shipped east to the board and 

 paper mills, as most of the counter-board mills are in or near New 

 England. It is also a considerable item when it is recalled that the 

 board and paper manufacturer must remove more or less (and in 

 some cases practically all) of the wood during the manufacturing 

 process before a pulp is obtained suitable for his purpose. More- 

 over, the physical condition of the material is such that it is more 

 amenable to chemical pulping processes, yielding to less expensive 

 processes and producing a more uniform and satisfactory product. 



MILL TESTS ON THE MANUFACTURE OF MEDIUM FLAX TOW. 



On account of previous and satisfactory laboratory results on flax 

 tow and because of the satisfactory condition of the tow industry 

 near the flax region, it was decided to be advisable in continuing 

 board tests to employ flax tow instead of flax straw, as had been done 

 up to this time. With this in view, a cooperative test was made in 



Fig. 7. — Small samples of flax straw and tow. From right to left : Straw, coarse tow, 

 medium tow, fine tow, and extra fine tow. 



a large tow mill at St. Paul, Minn., in which 24.8 tons of straw 

 were manufactured into 14.7 tons of medium tow, or 59.3 per cent of 

 the original straw, which yield is believed to be somewhat higher than 

 that obtained in ordinary practice. The bales average 100 pounds, 

 and 15 tons can be loaded into a car. This lot of tow was shipped to 

 a counter-board mill in Maine, where cooperative board tests were 

 made later, while four bales were sent to the Washington laboratory 

 for preliminary tests as to the most suitable method of treatment. 

 From observations made during this tow test, it was evident that by 

 very slight modifications of the tow machinery considerably more 

 woody matter could be removed, greatly to the advantage of the paper 

 manufacturer. 



LABORATORY TESTS ON THE TREATMENT OF MEDIUM FLAX TOW. 



The tow used in these tests was that manufactured at St. Paul, 

 as previously described. In order to obtain an idea of the amount 

 of loose woody matter still remaining in the tow, a weighed quantity 

 was shaken out lightly by hand, yielding 16 per cent of woody shives. 

 These shives are of no value to the paper or board manufacturer, and 



