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 : — 



Per cent. 



Moisture ... ... ... ... 0.4 



Caoutchouc ... ... ... ... 95. I* 



Resin ... ... ... ... 2.2 



Proteid ... ... ... ... 2.1 



Ash ... ... ... ... 0.2 



^ Including 1. 3 per cent, of " 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, 1911. 



Dear Sirs, 



In continuation of my letter of the T5th 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 

 Ilth'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 ... ... ... i.i 



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 ys follows: — 



Per cent. 



Moisture ... ... ... ... 0.9 



Caoutchouc ... ... ... ... 919* 



Res"n ... ... ... ... 2.7 



Saccharoid substance ... ... ... 1.3 



Proteid .. ... ... ... 2.8 



Ash ... ... ... ... 0.4 



Including 5.7 per cent. " insoluble caoutchouc." 



