336 
London, 17th, February , 1911. 
COPY. 
( From Imperial Institute, London, S. W . ) 
15th February, 1911. 
Messrs Gow, Wilson and Stanton Ltd. 
13 Rood Lane, E. C. 
Dear Sirs, 
The three specimens of smoked rubber from the Botanic Gardens 
at Singapore, which were forwarded with your letter o f the 2ist 
December, have now been examined with the following results: — 
No. I. A this sheet of dark brown rubber, slightly sticky on the 
surface, and having a strong odour of creosote. The rubber was 
fairly strong but appeared to be rather deficient in elasticity, as 
strips when stretched elongated very considerably and showed little 
power of recovery. 
The rubber had the following composition 
Rubber as received. 
Composition of dry 
rubber. 
Per cent. 
Per cent. 
Moisture 
2.0 
Caoutchouc 
80.7 
Resin 
5.5 
Proteid 
4.1 
Insoluble matter 
7-7 
82.3 
5-6 
4.2 
7-9 
100.0 
100.0 
Ash 
1.0 
1.0 
The results of the analysis show that this specimen is abnormal 
in containing a large proportion (7.7 per cent) of matter insoluble in 
chloroform, and a very high percentage of ash. The insoluble por- 
tion consisted ef dark brown flocculent matter which differed in 
appearance from the so called “ insoluble caoutchouc ” frequently 
present in Para Rubber. The amount of resin is very high for Para- 
rubber and in this respect the sample resembles those previously 
examined. The percentage of proteid is also high. 
No. 2. The sample consisted of pieces of light brown smoked 
sheet and biscuit which were free from all traces of stickiness. The 
rubber appeared to be a little stronger than No. I., but like the latter 
was easily extended permanently on being stretched. 
The rubber had the following composition, 
Per cent. 
Moisture 
Caoutchouc 
Resin 
Proteid 
Ash 
0.5 
94.1* 
3-2 
2 1 
0.1 
* Including 1.1% of insoluble caoutchouc.” 
The percentage of resin, proteid and ash are all much lower in 
this specimen than in No. I, and the amount insoluble in chloroform 
is only 1. 1 per cent compared with 7.7 per cent in the preceding 
sample. 
