516 [June 1908. 



GUMS, RESINS, SAPS, AND EXUDATIONS. 



RUBBER SAMPLES PROM INDIA. 



Para Rubber from Mbrgui, Burma. 



This sample of Para rubber (Hevea bra- 

 siliensis) was prepared from trees in the 

 Government plantation at Mergui, and 

 was forwarded to the Imperial Institute 

 for examination and valuation. The 

 sample weighed 49 grams, and consisted 

 of two thin sheets of pale rubber, which 

 was clean and well prepared. The 

 physical properties of the rubber were 

 very satisfactory. 



A chemical examination furnished 

 the following results : — 



Moisture 



Caoutchouc 



Resin 



Proteid 



Ash 



Per cent. 



0'5 

 95-2 

 1*6 

 24 

 0-3 



The rubber was valued a 5s. 6d. per 

 lb. in London, fine hard Para from South 

 America being quoted on the same day 

 at 5s. 2d. per lb., and Para biscuits from 

 Ceylon and the Federated Malay States 

 at os. 6d. per lb. 



This rubber is of excellent quality, 

 and compares favourably in composition 

 and physical properties with sample of 

 Para rubber from Ceylon and the Fe- 

 derated Malay States. Consignments of 

 similar character would find a ready 

 sale at good prices. 



Cryptostegia Grandiplora Rubber 

 prom India. 



Three samples of the rubber of Cryp- 

 tostegia grandiflora, received from India, 

 have been examined at the Imperial 

 Institute, and the following summary of 

 the results may be given :— 



Sample from Madras. 



This sample consisted of three flatten- 

 ed cakes, weighin .ogether about 1 lb. 

 They were dark brown externally, but 

 much lighter and slightly porous within ; 

 the pores contained a small amount of 

 uncoagulated latex and a quantity of 

 dark-brown liquid having an acid reac- 

 tion ; a little vegetable impurity was also 

 present. The rubber on arrival was 

 soft but not sticky, very elastic, and 

 possessed fair tenacity. After keeping 

 for some time, however, it hardened a 

 little and then exhibited a tendency to 

 tear when stretched. 



A chemical examination gave the 

 following results :— 



Calculated 



Sample as for dry 



received, material. 



Per cent. Per cent, 

 Moisture ... 24'7 



Caoutchouc ... 67'4 89'5 



Resin ... 5-9 7'9 



Insoluble impurity 2*0 



2-6 



It will be seen from these figures 

 that the rubber is of very fair quality, 

 the dry material containing 7'9 per 

 cent, of resin and 89 5 per cent, of 

 caoutchouc. The amount of moisture in 

 the sample as received was excessive, 

 but this could be remedied by more care- 

 ful preparation. 



A sample of the rubber, together with 

 a statement of the above results, was 

 submitted for commercial valuation to 

 brokers, who reported that it would 

 be worth about 2s. 4d. per lb. in London 

 (August, 1903). 



Sample from Jalaun. 



This sample was an irregular mass of 

 rubber, almost black throughout, porous 

 but quite dry, and contained frag- 

 ments of bark distributed through it. 

 The rubber was rather soft and slightly 

 sticky ; it exhibited very fair elasticity 

 but was somewhat deficient in tenacity. 

 As in the case of the specimen from 

 Madras the tenacity of the rubber dimin- 

 ished on keeping. 



An analysis 

 results :— - 



gave the following 



Moisture 



Caoutchouc 



Resin 



Sample as 

 received. 

 Per cent. 



... 5-5 

 ... 79-9 

 ... 8-5 



Calculated 

 for dry 

 material. 

 Per cent. 



84-5 

 9'0 



Insoluble impurity 61 



The sample from Jalaun therefore con- 

 tained more resin and foreign matter 

 than that from Madars, and its physical 

 characters were not quite so satisfactory. 

 The brokers to whom it was submitted 

 valued it at Is. 6d. per lb. compared 

 with 2s. 4d, per lb, for the Madras 

 specimen. 



Sample from Bombay. 



It is stated that the climbing plant 

 Cryptostegia grandiflora is very common 

 in the Bombay Presidency, and that if 

 the rubber is of marketable quality 

 large supplies could be obtained. 



