SUITABILITY OF LONGLEAF PINE FOR PAPER PULP. 9 
Table 1. — Record of semicommercial tests using the sulphate process — Continued. 
Chemicals charged per 100 pounds 
basis). 
of chips (bone-dry 
Duration of cooking. 
Cook 
No. 
S0 2 
All 
At 
At 
Maximum 
cooking 
com- 
sodium 
zero 
temperature. 
NaOH. 
Na 2 C0 3 . 
Na 2 S. 
pounds 
as 
Na 2 S0 3 . 
Na 2 S0 4 . 
com- 
pounds 
as Na 2 0. 
Total. 
gauge 
pres- 
sure. 
gauge 
pres- 
sure. 
Pounds. 
Pounds. 
Pounds. 
Pounds. 
Pounds. 
Pounds. 
Hours. 
Hours. 
Hours. 
°F. 
° C. 
171 
15.0 
0.8 
7.5 
1.0 
7.5 
21.8 
3.0 
0.1 
2.8 
331 
166 
77 
20.0 
1.2 
10.0 
1.3 
9.9 
29.1 
3.0 
.2 
2.3 
331 
166 
81 
15.1 
.8 
7.5 
1.0 
7.5 
21.9 
3.0 
.1 
2.5 
331 
166 
85 
15.0 
.8 
7.5 
1.0 
7.5 
21.8 
3,0 
.1 
2.5 
331 
166 
92 
12.0 
.6 
7.5 
1.0 
7.5 
19.4 
3.0 
.25 
2.5 
331 
166 
98 
12.0 
.6 
6.0 
.8 
6.0 
17.4 
5.0 
.1 
4.3 
331 
166 
113 
20.0 
1.1 
10.0 
1.3 
10.8 
29.4 
3.0 
.25 
1.0 
331 
166 
138 
20.0 
1.0 
10.0 
1.3 
10.0 
29.0 
3.0 
.1 
2.8 
331 
166 
141 
20.0 
1.1 
5.0 
.7 
10.0 
24.8 
3.0 
.1 
2.5 
331 
166 
146 
15.0 
.8 
7.5 
1.0 
7.5 
21.8 
3.0 
.2 
2.3 
338 
170 
147 
15.0 
.7 
7.5 
1.0 
7.5 
21.8 
3.5 
.3 
2.8 
338 
170 
148 
15.0 
.7 
7.5 
1.0 
7.5 
21.8 
3.5 
.2 
3.0 
338 
170 
Digester pres- 
Steam 
pres- 
Appar- 
Duration of beater 
sures per square 
inch. 
ent con- 
densa- 
treatment. 
Rea, 
per 
square 
tion 
Strength 
ratio 
Strength 
factor 
weight 
of 
Cook 
No. 
per 
pound 
ofchips 
(ibone- 
dry 
basis). 
pulp (bone-dry 
Maxi- 
Blow- 
inch 
at di- 
basis). 
Total. 
At 
light 
At 
stiff 
of paper. 
of paper. 
papers 
tested. 
gauge. 
ing. 
gester 
inlet. 
brush. 
brush. 
Lbs. per 
solid 
Pounds. 
Pounds. 
Pounds. 
Gallons. 
Per 
cord. 
Hours. 
Hours. 
Hours. 
Pounds. 
171 
90 
40 
105 
10.20 
61.2- 
2.172 
3.5 
1.5 
2.0 
0.60 
0.50 
76 
77 
90 
40 
105 
.50 
45.3 
1,609 
3.5 
2.0 
1.5 
1.15 
.91 
31 
81 
90 
50 
103 
.58 
47.9 
1,700 
5.0 
2.5 
2.5 
1.08 
.93 
44 
85 
90 
50 
108 
52.0 
1,846 
1, 733 
7.0 
3.0 
4.0 
.91 
.87 
38 
92 
90 
40 
110 
.49 
48.8 
6.5 
2.5 
4.0 
.86 
.70 
28 
98 
90 
40 
108 
.50 
51.8 
1,839 
4.5 
1.0 
3.5 
.60 
.56 
28 
113 
90 
40 
100-95 
.32 
48.6 
1,725 
6.0 
2.0 
4.0 
.70 
.59 
37 
138 
90 
90 
40 
40 
110 
108 
46.1 
44.2 
1,637 
1,569 
141 
8.5 
4.5 
4.0 
1.02 
.86 
36 
146 
100 
40 
105 
54.9 
1,949 
9.0 
4.0 
5.0 
.72 
.68 
45 
147 
100 
40 
115 
.41 
49.1 
1,743 
6.5 
4.0 
2.5 
.92 
.71 
37 
148 
100 
40 
115 
.63 
48.4 
1,718 
8.5 
4.0 
4.5 
1.02 
.77 
33 
(P. L.— 138, S. L.— 176.) 
i A portion of the digester liquor was lost, due to leaks during the early stages of cooking. 
SEVERE COOKING TREATMENTS. 
The effect of more severe cooking treatments, produced mainly 
by greater initial concentrations and amounts of active cooking 
chemicals, was evidenced by the thoroughly cooked or overcooked 
pulps from cooks 77 and 141 (Table 1). The crude pulps were not 
only free from chips and shives, but also seemed to be soft and 
fluffy. The papers made from the beaten pulps, however, were of 
very superior quality with regard to resistance to wear, toughness, 
and strength, the strength factors being 0.91 and 0.86 for cooks 77 
and 141, respectively. Both pulps became slightly hydrated during 
the beater treatments, which produced a parchmentizing effect and 
increased the strength and toughness. Either of the papers could be 
24542°— 14 2 
