UTILIZATION OF AMERICAN FLAX STRAW. 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 &nd 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, 
$24 ; extra fine, $32. These prices were the quotations in September, 
1911, 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 general 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 the paper manufacturer. In the case of medium tow, for example, 
2 tons of straw are required to make 1 ton of tow, which is a consider- 
