337 
No. 3. Two pieces of smoked biscuit rubber, one light brown and 
the other dark brown ; the specimens showed no trace of stickiness. 
The physical properties of the rubber resembled those of No. 2. 
The results of the chemical examination were as follows : — 
Moisture 
Caoutchouc 
Resin 
Proteid 
Ash 
* Including 1.3 per cent 
of 
Per cent. 
0.4 
95.1* 
2.2 
0.2 
“ insoluble Caoutchouc.” 
This sample is the best of the three specimens so far as chemical 
composition is concerned. 
I shall be glad to learn the age of the trees from which these 
rubbers came and to have some information as to how they were 
prepared. It may then be possible to discuss further their peculiarities. 
COPY. 
Imperial Institute. 
23rd. February, igil , 
Dear Sirs, 
In continuation of my letter of the 15th instant, I now send you 
the following report on the three further specimens of smoked Para 
rubber from Singapore which were forwarded with your letter of the 
Iltht January. 
No. 4. Two small pieces of thin sheet rubber of light brown 
colour. The rubber was strong, but easily elongated when stretched 
and exhibited little power of recovery. 
The analysis gave the following results : — 
Per cent. 
Moisture ... ... ... ... 3.5 
Caoutchouc ... ... ... ... 89.9* 
Resin ... ... ... ... 2.6 
Saccharoid substance ... ... ... 1.1 
Proteids ... ... ... ... 25 
Ash ... ... ... ... 0.4 
* Including 4.8 per cent. “ insoluble caoutchouc.” 
No. 5. Two small pieces of thin sheet rubber of dark brown 
colour. The rubber was strong and exhibited greater elasticity than 
No. 4. Its composition was found to be as follows : — 
Per cent. 
Moisture ... ... ... ... 0.9 
Caoutchouc ... ... ... .... 91.9* 
Res n ... ... ... ... 2.7 
Saccharoid substance ... ... ... 1.3 
Proteid ., ... ... ... 2:8 
Ash ... ... ... ... 0.4 
* Including 5.7 percent. “ insoluble caoutchouc.” 
