20 BULLETIX 322, U. S. DEPARTMENT OF AGRICULTURE. 
Fiber-board manufacturers would do well to pay more attention to 
the reaction of their waste liquors. A few drops of 1 per cent phe- 
nolphthalein in 50 per cent alcohol dropped into about a quarter of an 
ounce of the waste liquor should produce an intense red color at once. 
MILL TESTS OX THE MANUFACTURE OF FIBER BOARD. 
Fiber-board mill tests were again undertaken in a fiber-board mill 
in Maine, but flax tow was used instead of the straw that was 
employed in the previous work. The regular machines were used 
in all of these tests and the work was performed by the regular mill 
employees; in other words, the flax tow was subjected to actual com- 
mercial manufacturing conditions, although in some of the tests 
slight changes in procedure were made, as will be shown. 
Bleach Xo. 2o^. — A charge of 4,062 pounds was treated with 14.6 
per cent of burned lime by slaking 578 pounds of the lime in 1,600 
gallons of water in the bleach boiler, then adding the charge of tow. 
Direct steam was admitted, and the pressure was brought up to 110 
pounds in 3 hours and maintained for 4 hours, after which the 
pressure was relieved in 2 hours and the charge dumped. 
After remaining on the drain floor over night this stock was 
made into a 500-pound beater furnish of one-third flax tow. one- 
third mixed strings, and one-third board cuttings, in the following 
manner : The mixture of tow and mixed string was washed in the 
beater for 2 hours, when the board cuttings and sulphite screenings 
were added and the charge beaten off in a total of 12 hours. Near 
the end of the beating, the filler, color, and size were added. This 
stock was run over a 44-inch wet machine, loft dried, and put 
through the board calenders. The. wet boards from the wet ma- 
chines measured 38 by 44 inches, and after they were dried and 
calendered they measured 33 by 44 inches, which is about the correct 
amount of shrinkage. These boards were sold in the trade, but not 
as counter boards, as they were too brittle for that grade. The 
brittleness was due, according to the management and employees, 
to the fact that the stock was beaten too short. In working with 
any new material, its characteristics and differences must be learned 
before its full possibilities can be developed, and many failures must 
be expected during the earlier stages of development. 
Bleach Xo. 235. — This bleach was made in the same manner as 
Xo. 234, but 15 per cent of lime was used and the charge cooked 
at a steam pressure of 75 pounds for 9 hours, the total time of cook- 
ing being 12 hours. The stock from this bleach was used in the 
same furnish and manner as that of bleach Xo. 234. This furnish 
was beaten off in a total of 12 hours, loaded, colored, and sized, as in 
the previous test. The stock showed up very well in going over the 
Avet machine, giving a board measuring 38 by 44 inches wet. which 
after loft drying and calendering measured 33 by 44 inches. This 
