September, 1908.] 



211 



Saps and Exudations. 



ANALYSIS OF RUBBER SAMPLES 

 FROM INDIA: FIOUS ELASTIC A. 



Several samples of Ficus elastica rubber 

 from India have been examined recently 

 at the Imperial Institute, and the results 

 obtained are recorded iu the following 

 account :— 



FlCUS ELASTICA RUBBER FROM ASSAM. 



Two specimens of this rubber from the 

 Kulsi Plantation in the Kamrup Divi- 

 sion of Assam were submitted for 

 analysis and valuation. 



(1) "Tree Rubber from Ficus elastica." 

 The specimen conistsed of an irregular 

 cake of rubber formed by the aggrega- 

 tion of thin strips. The rubber was 

 reddish-brown, clean, free from sticki- 

 ness, and exhibited good elasticity and 

 tenacity. 



A chimical examination furnished the 

 following figures : — 



Per cent. 

 Moisture ... ... 0"7 



Caoutchouc ... ... 78 



Resin 19-0 



Proteids ... ... 09 



Insoluble matter ... 14 



This rubber contains a little less resin 

 than " the tree rubber, " but on account 

 of its weak, sticky character it is much 

 inferior in value. The stickiness may 

 be due to the plan of placing the mats 

 covered with rubber iu the sun to dry. 

 It would be preferable to effect the dry- 

 ing in the shade so as to avoid over-heat- 

 ing the rubber. 



FlCUS ELASTICA RUBBER FROM INDIA. 



Two specimens from this rubber ob- 

 tained at Mukkie in the Kanoth Range 

 North Malabar, have also been examined 



(1) Ficus elastica, scrap rubber. 



A cylindrical lump of reddish-brown 

 rubber, made up of aggregated shreds 

 and weighing 12| oz. The latter was 

 clean, free from stickiness, but rather 

 weak. 



The rubber had the following com- 

 position :— 



Per cent. 



Mositure ... ... 0-9 



Caoutchouc ... ... 67*3 



Resin ... ... 281 



Proteids ... ... 0-9 



Insoluble mattter ... 2*8 



Ash 049 



The rubber was valued at 4s. 3d. to 

 Is. 6d, per lb. in London, the current 

 price of fine hard Para from South 

 America being os. 2d. per lb. 



The percentage of resin in this rubber 

 is higher than is desirable, but otherwise 

 it is of satisfactory quality and would 

 be readily saleable. 



(2) *' Mat Rubber from Ficus elastica." 



This was a piece of dark-brown rubber 

 composed of several thin sheets firmly 

 attached together. The rubber was 

 soft, sticky, and rather weak. 



The rubber was found to have the 

 following composition :— 



Per cent. 



Moisture ... . . 24 



Caoutchouc ... ... 80 "0- 



Resin ... ... 160 



Insoluble matter ... 1*9 



Ash 1-94 



•Including proteids. 



The specimen was valued at 2s. to 2s. 

 3d, per lb, in London, but would be diffi- 

 cult of sale on account of its soft, sticky 

 character. 



The sample was too small for complete 

 chemical examination, and consequently 

 it was not possible to determine the 

 amount of proteids present. The per- 

 centage of the later constituent is in- 

 cluded with the " caoutchouc." 



Ash 047 



The sample was valued at 2s. lid. per 

 lb. in London, with fine hard Para 

 quoted at 3s. 5^d. per lb. 



This rubber contains an excessive 

 amount of resin, which adversely affects 

 its physical properties. 



(2) Ficus elastica, " biscuit " rubber, 



A large circular biscuit of black rub- 

 ber weighing 8 oz. The rubber was clean, 

 free from stickiness, but deficient in i 

 elasticity and tenacity. 



A chemical examination gave the fol- 

 lowing results . — 



Per cent. 

 Moisture ... ... 4*0 



Caoutchouc ... ... 71 "2 



Resin ... ... 22-7 



Proteids ... ... 10 



Insoluble matter ... 1*1 



Ash 1-68 



The specimen was valued at 2s.5d. per 

 lb. in London, with fine hard Para from 

 South America quoted at 3s. 5id. per lb. 



This sample contains a little less resin 

 than the preceding specimen, but on 

 account of its dark colour it would not 

 realise such a good price — Bulletin of 

 the Imperial Institute, Vol. VI., No. 1. 

 1908. 



