50 
BULLETIN 
U. S. DEPARTMENT OF AGRICULTURE. 
Series V. 
ACID TO WOOD RATIO. 
125 per cent of H 2 0; 7.5 atmospheres; minute. 
Cook No. 
Sulphuric 
acid (per 
cent of dry 
wood). 
Yield of volatile acid (per cent of dry 
weight of wood). 
Acetic. 
Formic. 
Both. 
3S 
0.5 
. 75 
1.00 
1.40 
1.40 
1.80 
1.80 
2.50 
2.50 
4.00 
0.87 
1.43 
1.05 
1.4*7 
1.56 
2.11 
1.38 
1. 755 
1.67 
2.43 
0.430 
.253 
.443 
.355 
470 
.480 
.642 
.572 
.790 
.735 
1.30 
37 
1.6S3 
35 
1.493 
33 
1.812 
40 
2.030 
34 
2.59 
30 
2.022 
31... 
2.827 
45 
2.460 
36 
3. 165 
/ 
/ 
/ 
/ 
/ 
/ 
/ 
/ 
/ 
/ 
/ 
1 
1 
1 
0.6 
0.1 0.2 0.3 0.4 0.5 
YIELD IN % OF FORMIC ACID ON DRY WEIGHT OF WOOD 
Fig. 10.— Series lb, showing the variation in formic-acid yields, with varying cooking pressures. Cooking 
period, minutes. 
Both the yields of acetic and formic acid varied with the cooking 
conditions, although the former was the more constant of the two. 
The variations in the water to wood ratio in general seemed to be 
without effect on the yields of both acids, and this w r as to be expected. 
Increasing the pressure of cooking increased the amount of formic acid, 
particularly as shown in the curve for series lb in figure 10, and this 
was apparently due in part to sugar decomposition. Increasing the 
