592 



THE INDIA RUBBER WORLD 



[August 1, 1913. 



ANNUAL REPORT OF HENRIQUES LABORATORY, 

 BERLIN. 



AS will be recalled, the "Chemical Laboratory for Commerce 

 and Industry," of Dr. Robert Henriques, Berlin, has been 

 carried on since his death by his successors. Dr. Edward Marck- 

 wald and Dr. Fritz Frank. The special section devoted to 

 rubber was established in April, 1910, under the name of "Central 

 Rubber Bureau for the Colonics," and has just issued its third 

 annual report. 



Upon its removal to its present more commodious quarters 

 at 88 Liitzowstrasse, the rubber section was equipped with 

 a vulcanizing boiler and regenerating plant, as well as grinding 

 and sifting machinery. During the year under review, wash- 

 ing machinery on the system of Werner & Pfleiderer has been 

 added. The number of plantation companies belonging to the 

 Bureau has, within that period, increased from 24 to 26. 



Cordial interest has been shown in the work of the Bureau by 

 the German Colonial Office and its representatives at different 

 points. A lecture delivered by Dr. Marckwald, dealing with his 

 visit to the Usambara plantations and the measures proposed 

 for improving the quality of the rubber produced, was attended 

 by Dr. Schnee, Governor of German East Africa, and other 

 important officials. In this lecture the cultivation of Hevea in 

 suitable locations was advocated. Frequent communications were 

 maintained by the Bureau with the various organizations in 

 the German colonies. 



TECHNICAL WORK. 



Among the features of the technical work were the investiga- 

 tions as to the albumen content in rubber goods and the determi- 

 nation of albumen in crude rubber. Another feature was the 

 investigation of the "Mengwerl" juice, used by the natives of 

 East Africa in the coagidation of Manihot latex, in conjunction 

 with other coagulants. Various other technical points were dealt 

 with as more urgent work permitted. 



GENERAL WORK. 



Besides the strictly technical questions, a number of others 

 of a more general character were taken up. Castor oil seeds 

 from German New Guinea were found to yield an oil of first class 

 quality, while a variety of drugs from the German possessions 

 were also examined. Tests made with wild lemons from West 

 Africa showed that they yielded 5 to 7 per cent, of citric acid, 

 which can be used in the coagulation of rubber. 



East African tests of manuring and soil had to be partially 

 interrupted, in consequence of the difficulty experienced in pro- 

 curing the necessary labor. The results obtained, however, 

 showed that the rubber tree does not require a rich, heavy soil, 

 but that the fineness and depth of the earth have a material 

 effect upon growth and yield. 



SYNTHETIC OR ARTIFICIAL RUBBER. 



The so-called "fish-rubber" was examined, and found perfectly 

 valueless. Regarding synthetic rubber, in confirmation of previous 

 utterances of Dr. Marckwald, the situation is said to be that the 

 production of synthetic rubber has been successful in the labora- 

 tory, and to a small extent in the factory. For its production, 

 however, on a large scale, very important difficulties have to be 

 overcome. The opinion is expressed that a parity of price 

 with that of natural rubber may be expected in the future, but 

 up to the present no way has been shown of obtaining a parity 

 in quality, particularly as natural rubber, besides the rubber 

 substance proper, contains other and important elements, the 

 introduction of which into the artificial product has not so far 

 been successfully accomplished. 



ESTABLISHMENT OF STANDARD QUALITY. 



At the conference of East African plantation companies which 

 took place in April, Dr. Marckwald referred to the difficult 

 position of the German East African plantations, advocating 



united action on the part of planters and planting companies 

 as well as the establishment of a first-class standard quality. 

 While these proposals encountered some opposition, they met 

 with the expressed approval of such expert authority as Pro- 

 fessor Zimmermann. The effect upon East African rubber of 

 unskilful preparation is illustrated by the statement that from 

 March to December, 1912, German market quotations for first 

 class Para rubber fell about 7 per cent., while the reduction on 

 Manihot rubber was about 27 per cent. The trials of washing 

 under water, which have been in progress for a year at the 

 Bureau with Werner and Pfleiderer's automatic machine, have 

 led to favorable results. 



TESTS MADE. 



In the rubber section, 214 tests were made; including: Manihot 

 Glaciovii, 104; Kickxia, 47; Ficus, etc., 18; Hevea, 20; gutta 

 percha 7; balata, 3; other kinds, 15. 



The following results are deduced from these tests: 



1. That it is quite possible to obtain in German Africa Manihot 

 rubber of first class quality. 



2. That the Manihot rubbers obtained from latex, without 

 the addition of coagulating agents, are only of medium quality. 



3. That through the addition of certain salts in coagulation, 

 rubbers of special nerve are obtained. 



4. That the present method of the preliminary treatment of 

 Manihot rubbers in German East Africa, through washing, etc., 

 in very many cases has not the anticipated favorable effect 

 either qualitatively or commercially. In commenting on these 

 results it is remarked that rubbers coagulated with acetic acid 

 were of medium quality, while the treatment of the rubbers with 

 the roller produced unfavorable results. 



COMPARATIVE RESULTS OF VARIOUS COAGULANTS. 



Different coagulants were used with four groups of samples: 

 1, citric acid and calcium-phosphate; 2, magnesium-sulphate 

 and citric acid ; 3, magnesium-sulphate ; 4, magnesia-salt. All 

 these rubbers were much superior to the products obtained with 

 chloride of calcium and acetic acid. Some rubbers were pro- 

 duced which in strength and nerve surpassed all products hitherto 

 obtained. Citric acid, on account of its high market price, can 

 only be used where there is abundance of wild lemons. Such, 

 as has already been remarked, is the case in West Africa. On 

 the other hand, magnesium-sulphate is an extremely cheap coagu- 

 lant, a trial of which is recommended. 



NEW COAGULATION PROCESS. 



.'\ttention is called to a new process of coagulation patented 

 by Dr. Collosseus, based on the double transposition of the 

 albumen components in the latex. Even when used cold, this 

 process is said to be satisfactory, both as to speed and quantity. 

 It is claimed that rubbers thus produced vulcanize in half the 

 time required by others of like origin but differently prepared. 

 Mechanical tests are said to have shown them to be of excep- 

 tional quality, the vulcanized product having considerable nerve. 

 Such are a few of the salient points of this interesting report. 

 Though dealing specially with the German colonies, it contains 

 many features of general interest on the subject of rubber 

 cultivation. 



A GERMAN VIEW OF THE BRAZILIAN SITUATION. 



In commenting upon the recent happenings in Brazil, the 

 "Gummi Zeitung" expresses doubt as to the prospects of rubber 

 goods manufacture in that country. Should the Brazilian in- 

 dustry, however, gradually acquire importance, the abstention of 

 European countries, particularly Germany, from purchases of 

 Brazilian rubber might be anticipated. It is added that a heavy 

 loss for Brazil would be thus implied, as the consumption within 

 that country of its rubber production is not to be seriously 

 considered. 



