UTILIZATION OF AMERICAN FLAX STEAW. 17 



been thrashed in ordinary grain-thrashing machines, without retting, 

 and is very different in character from the flax tow of the spinning 

 mills. A comparatively small quantity is manufactured into insulat- 

 ing boards, such as are used in building construction and refrigerator 

 cars; also a very small amount is used in the manufacture of rough 

 twine. There are about 10 flax-tow mills in the flax region, the 

 largest of which consumes over 30,000 tons per year, while some use, 

 not more than 1.000 tons. 



The flax-tow machines consist essentially of a series of corru- 

 gated rollers operating in pairs under considerable pressure, through 

 which a uniform layer of straw is rolled. The woody portion is 

 crushed and broken into small pieces, which fall away between the 

 rolls and are further removed by dusting and screening devices. 



Fig. 6. — A truck load of flax upholstering-tow bales. 



Flax upholstering tow is sold under four grades and normally in 

 carload lots at the following prices: Coarse, $16; medium, $18; fine, 

 $2 1 : extra fine, $32. These prices were the quotations in September, 

 L914, for baled flax tow, f. o. b. St. Paul, Minn., at which point flax 

 straw can be bought at $7 per ton, baled, in carload lots. The dif- 

 ferent grades vary in the amount of woody matter removed and the 

 degree of softness of the tow (fig. 7). 



Considering these prices of tow, the amount of wood removed, 

 and the genera] physical condition of the material, it would seem 

 that tow would be a more desirable as well as a more profitable raw 

 material than straw for the fiber-board manufacturer, if not indeed 

 for i he paper manufad iirer. [n the case of medium tow. for exam pie, 



2 ton- of straw arc required l<> make 1 ton of tow. which is a consider- 



