SCIENCE AND INDUSTRY. 
The bark used for the remaining five experiments contained more moisture and 
less tannin, as shown below*:— 
Analysis of Bark used for Experiments Nos. 4 to 8. 
Particulars. per cent. 
Tannin ca Ay mn De .. A 37.18 
Non-tannins me: Aa oat et wee LOIDS, 
Insolubles.. hes Ne 7 Ne me, 39.78 
Water “3 us oat oP ba at 12.46 
Total ox se ey be: e 100.00 
In the following table results are given of the analyses of the spent barks:— 
Analyses of Spent Barks. 
. | Temperature | Tannin cal- Total 
Experi-| “of tail-end Tannin. | Non-tannin. | Insolubles. Water. culated on tannin in 
ment. vats. | original bark. | spent bark. 
per cent. percent, | percent. per cent. per cent. per cent. 
No.1 20 to 25° C. 19-22 3°16 66-02 11-6 11-68 31-10 
No.8 35° C. 14:79 2-59 71-02 11-6 8-35 22-90 
No. 7 40° C. 14-42 2-86 71+12 11-6 8-06 21-70 
No. 6 60° C. 12-35 3-89 72-16 11-6 6-80 18-30 
No.5 80° 8-20 3-99 6221 11-6 4-29 11-54 
No. 4 95° 4°20 2-32 81-88 11-6 2-09 5-56 
No. 3 95° 4-25 2-84 ; 81-31 11-6 2-10. 5-59 
The extraction results are summarized in the next table:— 
Hetraction Results. 
Temperature of 
Experiment. ib endivatse Tannin extracted. DD gre Tannin lost. 
per cent. per cent. per cent. 
No.1 20 to 25° C. 64-1 31-1 4-8 
No.8 .. Fv, 35° 74°35 22-9 2-75 
INOS Zameen < hs 40° 74-1 21-7 4-2 
NO WGy ay 60° 79°48 18-3 2°22 
INGD meee Nes 80° 84-82 11-54 3:64 
Nona. 7 90° 90°8 5-56 3-64 
INOw3 Be + ne 90° 90 6 5-59 3°81 
Discussion or RESULTS. 
Six days were required to finish each experiment after the last lot of bark 
was placed in the battery, and the barkometer values are shown for each liquor 
as it passes from this bark. These figures can be taken as approximately correct 
for all the liquors passing from any one lot of bark when the battery is working 
under normal conditions. The battery is not working under normal conditions 
before the bark in every vat is covered with liquor. The barkometer values of the 
last liquors for the third and fourth experiments seem to indicate that all 
the tannin found in the spent bark was in a state of solution when this bark 
was removed from the battery, and, therefore, better results might have been 
obtained by adding more vats to the battery, or passing more water through 
the bark. However, a greater proportion of soluble non-tannin would have 
adversely affected the value of these liquors. : 
TE 
4 
* It was extremely difficult. to extract the last traces of tannin with one litre of water as per the 
standard method, and the total solubles are given for a further extraction amounting to two separate 
volumes of 500 c.c. each. The first 500 c.c. gave a total soluble of 1:14 per cent. and there was a 
slight reaction with gelatine. The second 500 c.c. gave a total soluble of 1°23 per cent. and no re- 
action with gelatine. at 
156 
