and Magazine of the Ceylon Agricultural Society.— August, 1911. 187 



Among the valuable characteristics of this pro- 

 duct (designated Hevea Para) are the fol- 

 lowing: — The carbonic acid coagulates the latex 

 instantly. The nerve, strength and elasticity 

 are not only equal to but superior to what is 

 met with in case of Para, The metallic salts 

 present are carbonates, as a result of the car- 

 bonic acid treatment. The rubber is alkaline, 

 for carbonic acid is not destroyed by alkali, but 

 can exist in contact with it, vide the well-known 

 alkaline carbonic acid charged mineral Wiitnrs. 

 The solutions of this rubber have as high visco- 

 sity as those of Para, and the product obtained 

 on vulcanisation is the same. Carbonic acid 

 coagulation is the cleanest possible method, 

 and gives the purest and lightest coloured pro- 

 duct possible. On the other hand, Para rubber 

 is coloured by the smokiog process. Hevea 

 Para never moulds, for the carbonic acid re- 

 moves the plant-albuminoids which form a soil 

 for bacterial vegetation. Hevea Para oxidises 

 no more readily than does Brazilian Para. Rub- 

 ber coagulated by acetic acid soon acquires a 

 bluish surface colour. This is due to the de- 

 composition of residual albuminoids with form- 

 ation of phenols, which give the rubber its 

 bluish colour, and make it second quality. In 

 the new process we have for the first time a 

 latex coagulated by a gas, and not by a corro- 

 sive fluid, as in case of the strong acids. Briefly, 

 we have here the only re-agent which can give 

 planation Hevea rubber the same fine quality as 

 Brazilian Para, Another advantage of carbonic 

 acid is that it requires no fine manipulation. 

 Its use can be entrusted to the most ignorant 

 hands. 



Mr Petch— denied that it was possible for 

 any coagulum to prevent mould. 



The second longest discussion of the day was 

 raised by this paper which was very severely 

 handled by several of the English experts. Pro- 

 fessor Carmody said they were always ready to 

 hear of any new coagulum, but he did not think 

 the lecturer had made out his case altogether 

 satisfactorily. — Dr. Stevens traversed the paper 

 from end to end, pointing out that most of the 

 statements were contentious statements. At the 

 same time he thoughtit might be worth while to 

 make a trial with carbonic acid. The arguments 

 used had not inspired much confidence in the 

 theory. — Dr Huber objected to the title "Hevea- 

 Para,"as Para they understood to be rubber 

 from Hevea. 



The afternoon was devoted to a joint meeting 

 of planters, manufacturers, and chemists, and 

 under the chairmanship of Dr. Torrey they dis- 

 cussed the question whether it was not possible 

 for the planter to devise ceitain tests by which 

 they could ensure 



THE STANDARDISING OF THEIR RUBBER. 



The Chairman, in opening the discussion, urged 

 that this was a matter of special importance to 

 tti6 planter. Immediately two planters arose and 

 said it was impossible for planters to under- 

 take tests on the field, and that they, on their 

 part, wanted to know what it was the manufac- 

 turers required and then they would endeavour 

 to supply it. 



Dr Hcber — said that though not a planter 

 by profession, he had planted rubber trees in the 



experimental gardens at Para, and he had done 

 a good deal in the way of testing samples of 

 rubber. He thought it would be possible for the 

 planter to get good relative results which would 

 be sufficient tor the purpose, and he indicated 

 several ways in which it could be done s 



Mr J Ryan— a planter — thought these sugges- 

 ted methods would be impracticable — Mr Potts 

 said the problem for the planter was not so 

 much to determine quality as to make from the 

 beginning careful tests of the latex, in order to 

 get absolutely uniform results.— The Chairman 

 agreed with this, and said that what was wanted 

 was not for the planter to distinguish qualities, 

 but to ensure that the quality of a given kind 

 should be permanent and reliable in subsequent 

 supplies. — Mr Francis Martin, as a manufac- 

 turing chemist, thought it possible something 

 could be done. 



Professor CALMODY-of Trinidad— said that as 

 regarded Castilloa they got uniform results in 

 the preparation of rubber by a centrifugal 

 machine invented by Mr Smith, of Tobago, and 

 an excellent quality was turned out. 



Mr Harvky— of South Mexico— spoke of the 

 juice of a plant found there which was used 

 in coagulation. He thought chemists might 

 investigate whether a preparation of this 

 could not be used throughout the world At 

 present their preparations would only keep a 

 very short time. He also urged that it was 

 not so much a question for the planter as for 

 the manufacturer. — Dr. Stevens, on the other 

 hand, thought that simple tests could be used 

 by the planter. — Mr. Gorringe said it would 

 be no good the planters making a test if the 

 brokers in London sold it not by that test, 

 but by feel and sight. 



The Chairman— in concluding the confer- 

 ence on the subject— urged the planters to see 

 what could be done in order to procure that 

 the rubber they supplied should be uniform 

 in quality. 



To the exhibit of the Imperial Institute re- 

 presenting the rubber resources of the Empire 

 the British South Africa Company contributes 

 a collection of specimens of the rubber-yield- 

 ing plants of Northern Rhodesia. These in- 

 clude specimens of Landolphia vines, which 

 are reported to grow luxuriantly in many dis- 

 tricts and to cover large areas of the country, 

 and also a number of specimens of various 

 roots from the bark of which root-rubber is 

 prepared. Additional interest is lent to the 

 exhibit by specimens of dried and mounted 

 leaves and flowers of the plants, further illus- 

 trated by coloured drawings. 



A very interesting and practical demonstra- 

 tion of the process of tapping rubber trees was 

 given on Saturday. The tapping of the trees 

 took place at the joint stand of the Soconusco 

 Rubber Plantations, Limited, and La Zacu- 

 alpa Plantations Company, Limited, situated 

 in King George's Hall, where specimens of 

 eight live Castilloa lactifiua rubber trees from 

 six to ten years of age from the estates were 

 exhibited. The foliage of the trees had been 

 cut away, and also the whole of the roots, 

 with the exception of about 1 ft. measured 

 from the bottom of the trunks. In spite of, 



