Part IV.] Puran Singh: Preparation of Tannin Extracts. 27 
Through the kindness of Mr. C. Rogers, Conservator of Forests, 
Pegu Circle, Rangoon, eight specimens of mangrove barks obtained from 
old and young trees of the same species were examined for com¬ 
parison of colour and tannin strength. The samples were collected and 
despatched by the Divisional Forest Officer, Andaman Isles, in a fresh 
and moist condition packed in gunny bags. Some portions of them were 
completely rotten when they arrived. The rotten portions were rejected 
and the sound bark was picked out and analysed. The following table 
gives the results of the examination of these, along with one specimen 
of mangrove bark drawn from old trees (locality unknown), which had 
been lying in the laboratory stores for about two years, for purposes of 
comparison :— 
Analysis of fresh Mangrove Bark from Andamans. 
1 
The yield 
of extract 
calculat¬ 
Mois¬ 
ture 
Mois¬ 
Colour 
ed on air- 
Serial 
Description. 
ture 
on 
Ash. 
Total 
solu¬ 
Non- 
Tan¬ 
measure¬ 
ment on - 5 
dried 
material. 
num¬ 
ber. 
on 
fresh 
bark. 
air- 
ble 
tannin. 
nin. 
solution 
with 20 
dried 
solids. 
in 1 cm. 
per cent. 
bark. 
cell. 
moisture 
from 100 
parts of 
the bark. 
Per 
cent. 
Per 
cent. 
Per 
cent. 
Per 
cent. 
Per 
cent. 
Per 
cent. 
Red. 
Yellow. 
1 
Rhizophora muc- 
ronata bark 
(from old trees) 
40-51 
8-84 
6-64 
45-88 
801 
37-87 
13 
39 
65-88 
2 
Rhizophora muc- 
ronata bark 
(from young 
trees) 
48-05 
7-43 
8-68 
31-92 
7-83 
24-09 
20 
57 
51-92 
3 
Rhizophora muc - 
ronata bark 
stored in the 
laboratory for 
about two years 
(from old trees) 
11-17 
10*31 
8-34 
3212 
8-7 
23-42 
22 
58 
52-12 
4 
Rhizophora con- 
jug it a bark 
(from old trees) 
47-77 
8 47 
17-46 
44-40 
9-62 
34*78 
9 
22 
64-40 
244 
