26 



Results of Examination. — The rubber was examined in the 

 Scientific and Technical Department of the Imperial Institute 

 and found to have the following percentage composition : — 



Moisture... 



... 3-6 



Caoutchouc (true rubber) ... 



... 64-3 



Resin 



... 101 



Albuminoid matter 



... 79 



Insoluble matter (including ash) 



... 141 



Ash 



... 8-22 



The percentage or resin and albuminoid matter are both a 

 little high, but the chief defect of the rubber is the presence of 

 the large amount of insoluble matter consisting of vegetable 

 and mineral impurities. The presence of mineral impurity 

 points to the contamination of the rubber, possibly the scrap 

 rubber present in the sample, by contact with the soil, and 

 precautions should be taken to avoid this in future The per- 

 centage of caoutchouc is rather low, but this is chiefly due to 

 the excessive amount of the impurities contained in the pre- 

 sent sample. 



Two specimens of the rubber of Cryptostegia grandifiora 

 from India were examined at the Imperial Institute in 1903. 

 A specimen forwarded by the Secretary of the Agri-Horticul- 

 tural Society, Teynampett, Madras, was analysed and the dry 

 material was found to contain 79 per cent, of resin and 26 per 

 cent, of insoluble impurity. A second sample from Jalaum, 

 which was rather inferior in physical characters, contained 9"0 

 per cent, of resin and 6*5 per cent, of insoluble impurity. Both 

 these specimens therefore contained less resin and insoluble 

 impurity than the present sample from Bombay. The amount 

 of resin in the rubber may vary with the age of the plants, a 

 larger percentage being present in the products from young 

 vines. 



Commercial Valuation. — A sample of the rubber was sub- 

 mitted for valuation to brokers who reported that it was rather 

 sticky and slightly heated, and would probably be worth 3s. 6d. 

 per pound in London at the present time. For comparison 

 with this valuation ib may be stated that the current value of 

 fine hard Para from South America (the market standard for 

 price) was 5s. 4d. per pound. 



Conclusion and Recommendations. — The investigation has 

 shown that this sample of the rubber of Cryptostegia grandi- 

 fiora from Bombay is of very fair quality, and there is little 

 doubt that the carefully prepared product would sell readily in 



