18 
BULLETIN 322, U. 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 
medium tow, fine tow, and extra fine tow. 
Straw, coarse tow, 
a large tow mill at St. Paul. Minn., in which 24.8 tons of straw 
were manufactured into 11.7 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 
