48 
BULLETIN 983, U. S. DEPARTMENT OF AGRICULTURE. 
Commercially, the subject of extraction, covering the questions of 
size, design, and number of cells in a diffusion battery, is one that 
has received a great deal of attention in the beet-sugar industry. In 
the light of data obtained in units of commercial size in the ethyl- 
alcohol industry, it may be said that at least a 5-cell draw — that is, 
passing the extracting medium through 5 cells in rotation — is neces- 
sary, and that a 6 or 7 cell draw is more desirable. The amount of 
water to be used and the proper end point or time of drawing must 
be determined for each particular battery, and with proper care and 
supervision the efficiency of the entire operation can be maintained 
at a 92 per cent extraction with a 10° to 11° Brix acid juice corrected 
for temperature. 
VOLATILE ACID YIELDS. 
In addition to the sugars obtained as hydrolytic products, acetic 
and formic acids were also obtained in varying amounts. The yields 
are given on the acid-yield sheet in the Appendix, in addition to the 
following tables, in which the cooks have been outlined in the differ- 
ent series as given before under pressure, time, water to wood and 
acid to wood ratios : 
Series I&. 
PRESSURE VARIABLE. 
1.80 per cent of H : S0 4 ; 400 per cent of H 2 (water); minute. 
Cook Xo. 
Pressure. 
Yield of volatile acid (per cent of dry- 
weight of wood). 
Acetic. 
Formic. 
Both. 
20 
6. 5 
1.25 
1.22 
1.62 
1.60 
0.105 
.185 
.220 
1.355 
15 
7.5 
1.405 
16 
7.5 
1.840 
19 
9.0 
.443 
2.043 
• 
Series III. 
TIME VARIABLE. 
2.5 per cent of H2SO4; 125 per cent of H 2 0; 7.5 atmospheres. 
Cook No. 
Time of 
cook 
(minutes). 
Yield of volatile acid (per cent of dry 
weight of wood). 
Acetic. 
Formic. 
Both. 
31 


10 
10 
20 
45 
90 
1. 755 
1.670 
1.67 
2.62 
2.360 
2.915 
0.572 
.790 
1.090 
.340 
1.450 
2.827 
45 
2.460 
32 
2.760 
47 
2.96 
46 
3.81 
56 
1.492 i 4.407 
55 
2. 140 . 440 1 2. 580 
