74 



THE INDIA RUBBER WORLD 



[December i, 1901. 



ADULTERATION OF FINE PARA RUBBER. 



[from the "GUMMI-ZEITUNG," DRESDEN.] 



ADULTERATION of rubber has always been practiced, 

 especially of the African sorts, and in isolated instances 

 also of those coming from Para, but these were generally an 

 exception. But it seems that the adulteration of Para rubber 

 during the past season has assumed such proportions that it is to 

 the utmost interest of the importers, as well as the manufactur- 

 ers, to call public attention to this fact, in order to make future 

 adulterations impossible. It is self-evident that these adulter- 

 ations are perpetrated at the place of production — /. e., along 

 the Amazon and its tributaries — and the importers can exert 

 their influence only in so far as to call the attention of their cor- 

 respondents to this evil and urge them to a sharp inspection 

 before accepting the goods. No doubt this is the rule with 

 most firms. But there are some firms who consider adultera- 

 tions up to 10 per cent, as nothing unusual, and take it for 

 granted that the product just now is of no better quality, 

 and that the manufacturers have to take it as it comes. The 

 experience which one of our largest factories had with import- 

 ers, and which is given below, will show the true condition of 

 affairs. 



The adulterations consist in some instances in the mixing of 

 medium with fine Para, and in others in the admixture of 

 farina flour, and this last named one particularly causes the 

 manufacturers the greatest trouble. It seems peculiar that 

 these adulterations occur almost exclusively in the so called 

 soft or brown cure (Islands) rubber, and therefore in the rub- 

 ber district of the lower Amazon, embracing the islands in 

 that river near the city of Para, while the so called hard fine 

 cure (Upriver), commg from the upper part of the Amazon 

 and its tributaries, is free from this adulteration. It seems 

 that the rubber gatherers living remote from the large rubber 

 center, Para, are as yet not sufficiently cultivated to practice 

 the mixing of farina, needed by them for food, with rubber 

 milk and turning it into Caoutchouc. 



The firm already mentioned had sufficient proof of a 10 per 

 cent, adulteration with this flour, and so informed the house 

 from which the rubber was obtained and placed it at their dis- 

 posal. But, strange to say, this firm, an English house, de- 

 manded that the rubber be returned to Liverpool for inspec- 

 tion. It IS the custom for sales of Para rubber to be made on 

 the condition " f. o. b. Liverpool," but to expect that a quan- 

 tity of rubber, which has been declared as adulterated by ex- 

 perts, should be returned to Liverpool for inspection, seems to 

 be rather strong. The factory refused, and the matter was 

 arranged amicably. How much dependence can be placed on 

 such an inspection in Liverpool is shown by what follows: 



This same factory bought a parcel of 10 tons soft brown cure, 

 the selling firm promising to have this lot undergo specially 

 careful inspection and selection. The goods were accompanied 

 by the certificate of a Liverpool broker, which read as follows: 



We hereby certify that .... cases soft cure Fine Para rubber, shipped 



by Messrs per to Hamburg, were duly weighed and tared 



in the presence of our man , and carefully inspected by him, and 



are of fair usual quality. 



According to this certificate the Liverpool broker had sent a 

 workman to "carefully" inspect the goods. How carefully 

 this inspection had been made is shown by the fact that, on an 

 inspection being made in the factory, exactly 10 per cent, of 

 flour- adulterated rubber was found. The man had only looked 

 at the goods superficially and had not even deemed it worth the 

 trouble to cut the pieces in one of the cases ; otherwise the 

 adulteration could not have escaped him. 



These adulterations with flour are at times so great that, on 

 cutting through the pieces, the flour can be seen and often falls 

 out. Such pieces, owing to their high specific gravity — given it 

 by the flour — sink in water, and even if they float it is not positive 

 proof of their purity, much ingenuity to disguise the adultera- 

 tions being resorted to. Sometimes only the inner layers con- 

 tain flour, while the outer ones, to the thickness of from 5 to 

 10 millimeters, consist of fine Para. The worst feature of this 

 flour adulteration is that washing does not remove it, and it 

 remains in the washed rubber. A simple and absolutely sure 

 reaction on flour is the reaction of a solution of iodine, which 

 immediately gives a deep blue color to bodies containing starch. 

 If a solution of iodine is applied with a brush to a piece of rub- 

 ber containing flour, the portion containing it will immediately 

 turn blue, while the others will retain their usual light color. 

 Washed rubber, containing flour, will, on being tested with 

 iodine solution, turn a deep blue ; this proves that the washing 

 process does not remove all the flour. 



As mentioned above, the importers are not to blame for this 

 adulteration. Their fault lies in the fact that the houses across 

 the sea which are represented by them do not exercise sufficient 

 care, and it seems strange that some firms pronounce such rub- 

 ber adulterated with flour " fair average quality." Happily, 

 these houses are the exception. Another large English house, 

 to which the firm had sent samples and asked for advice, wrote 

 as follows : 



It happens off and on that a single piece of <fn/«yf«f (medium), or 

 one that has been adulterated with farina flour, escapes detection, but 

 we must admit that an admixture of such pieces, and of the percentage 

 you mention, has never been experienced by us in bona fidi imports. 

 We are well acquainted with the quality in question, receiving it regu- 

 larly from Para and from Manaos, where our houses separate it, and 

 here of course it is sold at its value, according to the amount of adul- 

 teration. The standpoint assumed by your purveyor seems, in onr 

 opinion, to be wrong in every respect ; with us no question would arise 

 in the market, as to whether a parcel, adulterated to any great extent, 

 with such rubber, was within the scope of contract, and the buyer cer- 

 tainly has the privilege to refuse such goods. The action of the broker 

 who furnished your purveyor with the certificate is beyond our compre- 

 hension. If the parcel shipped to you consisted of "original import," 

 the shippers on the Amazon must have been extraordinarily careless. 

 Of course it is outside of our province to say whether the rubber reached 

 you in the same condition in which it was received here, or if something 

 " queer" happened to it in Liverpool. 



It would certainly be of interest to know if such adulterations 

 are experienced by others, and we beg those manufacturers 

 who have met with like conditions to express themselves on 

 this subject. 



THE OFFICE OF "LATEX." 



HW. BENNETT, president of the Tehuantepec Rubber 

 Culture Co., who has spent many years in Mexico and is 

 familiarwith its products, brings forward an interesting theory 

 regarding the office of the latex in tropical trees and vines. It 

 is of course well understood that the latex or milk from which 

 rubber is produced is in no sense a sap. As far as is known, 

 it does not feed the tree in any way, and its presence or absence 

 has nothing whatever to do with the nurture or growth of it. 

 Mr. Bennett's theory is that, tropical vegetation is so exposed 

 totheattacks of myriads of insects that nature hasgiven to it the 

 protection of the /a/«-, which appears to be unpalatable to such 

 insect devourers. The theory is a plausible one, as almost every 

 sort of tropical tree, particularly those having quick growth 

 and soft wood, have some such milk, entirely distinct from the 

 sap. 



