12 BULLETIN 322, U. S. DEPABTMEXT OF AGBICULTUBE. 
Chemical reduction was effected in a steel, rotary pulp boiler, 6 
feet long by 4 feet in diameter, which was supplied with a ther- 
mometer well, pressure gauge, and pipes for relief and direct steam 
inflow. 
Bleach No. 193. — A charge of 277 pounds (242 pounds, bone-dry 
weight) was treated with 15 per cent of burned lime (36.4 pounds) 
and 100 gallons of water, the lime being slaked in part of the water 
before being added. Direct steam was admitted, so as to bring the 
charge up to 148° C, or 50 pounds steam pressure, in 1 hour; then 
regulated so as to maintain this pressure for 10 hours, after which 
the pressure was relieved and the contents removed. This stock was 
followed down with a fairly light roll and washed for 3 hours in a 
400-pound beater, at which point the stock was removed, drained, 
pressed, weighed, and sampled for moisture content. From these 
data the yield was found to be 64.6 per cent of the sieved straw, or 
48.7 per cent of the original bone-dry straw. 
Bleach No. 194. — This bleach was made in the same manner as Xo. 
193 and beaten and washed 3 hours, after which the stock from Xo. 
193 was added to it in the beater. The combined stocks were beaten 
a total of 19 hours, the last 7 of which were fairly hard, the washer 
being used the first 4 hours. The long bast fibers were very strong 
and not easily reduced; likewise, the woody portion did not com- 
pletely reduce to the separated individual fibers, but remained as 
more or less fine shives, or cell aggregates. The washer used in this 
work was 60-mesh, while a much coarser, possibly 20 or 25 mesh, 
would have removed many more of the shives and given a far better 
product. This unsized and unscreened stock was pumped to the stuff 
chest and run over a 30-inch Fourdrinier paper machine, in conjunc- 
tion with a Jordan type of refiner. The stock acted well on the ma- 
chine wire, was strong after the second press rolls, did not cockle on 
the driers, but became very brittle on drying, doubtless due to the 
large amount of woody shives present. It was apparent that more 
wood must be removed from the finished product. This could be ac- 
complished by removing it from the straw before treatment, or by 
more severe chemical treatment, or by a harder beating and washing. 
Another test was made on the same lot of straw, which gave a sieving 
loss of 35 per cent of the original straw. 
Other bleaches. — Three bleaches, Xos. 202, 203, and 204, were made, 
similar to bleach No. 193, using 14.7 per cent of lime and treating 
10 hours at 160° C, equivalent to 60 pounds steam pressure. 
The stock from bleach Xo. 202 was beaten and washed eight hours 
in a 400-pound beater, following the roll .down fairly hard. At this 
point the stock was removed and weighed, giving a yield of 63.8 
per cent of the sieved straw, or 41.5 per cent of the original bone-dry 
straw. 
