SUITABILITY OP LONGLEAF PINE FOE PAPER PULP. 11 
All things considered, cooks 147 and 148, which may also be classed 
with those of medium severity, gave the best results. These two 
cooks were made under almost duplicate cooking conditions, approxi- 
mately as follows: Caustic soda and sodium sulphide charged per 100 
pounds of chips, 15 and 7.5 pounds, respectively; initial concen- 
tration of caustic soda in digester liquor, 26.5 grams per liter; initial 
volume of digester liquor per pound of chips, 0.68 gallon; total 
duration of cooking, 3.5 hours, of which 2.8 hours for cook 147 and 
3.0 hours for cook 148 were at a maximum gauge pressure of 100 
pounds per square inch. 
The crude pulps were slightly raw and contained some soft chips, 
which, however, broke up in the beater. The pulp from cook 148 
was hydrated during the beating treatment to such an extent that the 
paper made from it had a parchment-like appearance, the individual 
fibers being scarcely distinguishable from each other. This paper 
had good wearing properties and was very tough, with, a strength 
factor of 0.77. The pulp from cook 147 was not subjected to so 
long a beating treatment, and the resulting paper was not parch- 
mentized to the same extent as that from cook 148. It had a strength 
factor of 0.71, however, was very tough, and showed good wearing 
properties. The yield from cook 148 was 48.4 per cent, or 1,718 
pounds per solid cord, and from cook 147, 49.1 per cent, or 1,743 
pounds per solid cord. 
EFFECTS OF BEATING. 
The mechanical treatment given a kraft pulp has as important 
an influence on the properties of the resulting paper as the cooking 
treatment itself. A crude pulp which appears to be of little value 
can be made into strong high-grade paper if the proper beater treat- 
ment is employed, while the best pulps can easily be ruined by 
improper beating. The use of kollergangs or edge runners prelimi- 
nary to actual beating, or of stone rolls and bedplates in the beaters, 
and the determination by successive tests of the refining and beating 
treatments best adapted for a particular pulp undoubtedly would 
have resulted in papers of much better quality than those obtained. 
Nevertheless, many of the experimental papers were equal or superior 
to commercial kraft papers. 
The effect of different beater treatments was shown by a single 
series of tests on some of the crude pulp from cook 71 (Table 1). 
Separate portions of the pulp were treated in the 1-pound beater 
for periods of 0.5, 1, 2, 3, and 4 hours with the roll at light brush. 
The papers resulting from treatments of 2 hours or less were soft and 
weak, and had poor wearing properties, but for the longer periods the 
papers were firm and tough, with good wearing properties. Under 
the 4-hour treatment the fibers became hydrated, and a parchment- 
like paper resulted. The fibers of longleaf pine when reduced by the 
sulphate process seem to take up water and to become hydrated very 
