Schools and to a few others interested in agricultural experiments 

 who have promised to furnish periodical reports on the results 

 attained by thorn. 



7. Gryptostegia grandijlora. A sample of this rubber was 

 forwarded to the Imperial Institute in order that its quality 

 and commercial value should be ascertained. The report received 

 runs as follows : 



"The sample weighed about 13 ounces and consisted of a large porous lump 

 of rubber which had been formed apparently by the aggregation of thin sheets 

 and scrap. It was dark coloured, slightly sticky, and contained a considerable 

 quanitity of vegetable and mineral impurities. The rubber exhibited very 

 fair elasticity and tenacity. 



Results of examination. 



Ci The rubber was examined in the Scientific and Technical Department of 

 the Imperial Institute and found to have the following percentage composi- 

 tion : 



Moisture ... .,, . 3*6 



Caoutchouc (true rubber) ... . 64*3 



Resin ... ... . 10-1 



Albuminoid matter ... . 7*9 



Insoluble matter (including ash) . 14' 1 



Ash ... ... ... 8-22 



(e The percentages of 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 percentage of caoutchouc is rather low, 

 but this is chiefly due to the excessive amount of the impurities contained in 

 the present sample. 



" Two specimens of the rubber of Cryptosteyia cjrandiflora from India were 

 examined at the Imperial Institute in 1903. A specimen forwarded by the 

 Secretary of the Agri- Horticultural Society, Teynampett, Madras, was 

 analysed and the dry material was found to contain 7'9 per cent, of resin and 

 2*6 per cent, of insoluble impurity. A second sample from Jalaun, which was 

 rather inferior in physical characters, contained 9 percent, 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 varies with the age of the plants, a large percentage being 

 present in the product frcm young vines. 



Commercial valuation, 



" A sample of the rubber was submitted for valuation to brokers who 

 reported that it was rather sticky and slightly heated and would be worth 

 3$. 6d. per pound in London at the present time. For comparison with this 



