THE SUPPLEMENT TO THE 



Tropical Agriculturist and Magazine of the C. A. 8. 



Compiled by A. M. & J. FERGUSON. 



No. 3.] 



MAKCH, 1910. 



[Vol. VI. 



RUBBER PLANTS IN SINGAPORE 

 BOTANICAL GARDENS. 



Analytical Notes. 



Hevea Bkasiliestsis.- The latex was obtained 

 from one 32-year-old tree, tapped at 6-30 a.m. 

 No water was added to the latex, and the for- 

 malin added was carefully measured, so that 

 the amount of pure latex is known. In the 

 figures given below, this formalin has bee"n cor- 

 rected for so that they refer to pure latex. 



The total yield from this tree at one tapping 

 was 27 fluid ounces of latex. It was thick, white, 

 and of very agreeable odour. 



The coagulum obtained by use of acetic acid 

 was analysed and the amounts of. several of the 

 other constituents determined. The dry rubber 

 has the following composition : 



Rubber 

 Resin 



98.14 per cent. 

 1.86 per cent, 



Albumens were not determined (as they should 

 be for strictly accurate results). Theiramount 

 is small compared to the total, and the usual 

 acetone extraction gives figures that are near 

 enough to the truth for all ordinary purposes. 



The analysis of the latex is : — 



i Rubber 3!j.fi5 per cent 

 Coagulum 36,29 per cent J Resin 0.67 per cent 



I Ash 0.07 per cent 

 Serum oliils 2.63 per cent /Organic matter 2.30 per cent 



\Ash 0.33 per cent 



Water 61 - 08 per cent Water 61.08 per cent 



The solids soluble in water, (tannins, colouring 

 matters, pentoses, gums, sugars of the inosite 

 group, etc.,) form a brown sweet smelling mass 

 of extremely hygroscopic nature: The strength 

 and appearance of the rubber were very fine. 

 The percentage of 36 per cent, coagulable matter 

 in the latex is very high for Para and is in ac- 

 cordance with the rule that the percentage of 

 rubber in a latex increases as the tree gets older. 



WlLI.UGHBEIA FlRMA. 



The specimen was a vine about twelve years 

 old, in the Botanical (iardens, growing in the 

 jungle part „of the same. Greatest diameter of 



34 



stems about 2^ inches. The latex was found to 

 flow most readily from transverse cuts, but 

 coagulated so easily that collection as latex was 

 difficult. Some of the latex was collected as 

 such and added to the clots picked out of the 

 cuts. The rubber was dried in the air and 

 analyzed. The results are: — Rubber, 86 82 per 

 cent. ; Resin, 13'18 per cent. 



It was a very fine tough rubber, turning very 

 dark-coloured in a short time. Except for the 

 high resin content it is a first-class rubber. 



Chilocaepus Enervis. 

 This latex was obtained from a creeper in 

 the Botanical Gardens. It consisted of a mass 

 of twisted stems around a large cinnamon tree, 

 the largest circumference of any one stem being 

 about five inches. The latex ran quite freely, 

 without coagulating, from transverse cuts on 

 the thickest stems. The reaction was neutral to 

 litmus. Coagulating agents did not act readily, 

 and the whole was evaporated. It then was a 

 white brittle mass, very soft when hot. The latex 

 contained 42 per cent solid matter. Analysis 

 Dry Rubber 25'60 per cent ; Resin 74'40 per cent. 



The extracted rubber was a light-coloured mass 

 of little strength or elasticity, although not tacky. 

 It seemed to be rubber, but if really such, is 

 very poor. The resin is a pretty white substance, 

 crystallizing well from organic solvents. 



Landolphia Heudelotii. (Africa.) 



The specimen examined was a bush in the 

 Botanical Gardens, growing in an inferior clay 

 soil. Only a few feet in height with a diameter 

 of about two inches on some of the branches 

 the basal stem being larger. The latex ran 

 very slowly from transverse cuts and coagulated 

 rapidly. The rubber was obtained by picking 

 the clots from the cuts, and was handsome and 

 strong. The analysis of the dry rubber is :— 

 Rubber, 89"50 per cent. ; Resin, 10'50 per cent. 



The dry rubber is of a clear light brown 

 colour, not tacky, and very strong and elastic. 

 Compared to Willughbeia rubber, it has a better 



