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lion. Nothing piejudiees a rubber brand so much as continued 

 depreciation of quality. At first, price is considerably reduced, 

 and if continued the material is discarded by all good buyers, and 

 become relegated to the rubbish heap or unreliable products. 



All this has reference to what one may regard as accidental 

 adulteration arising from carelessness. Many rubbers are design- 

 edly loaded to gain weight. The readers will note how absurd 

 such a policy is, and how ultimately it must result in loss and dis- 

 credit. There is, however, another form of adulteration which will 

 in time destroy the reputation of any brand and effectively exclude 

 it from the markets of the world. I his is the designed admixture 

 of inferior gums, such as Euphorbia and many others of the resin- 

 ous class, with the intention of illegitimately increasing the imme- 

 diate profit. But the brand once detected in this condition will 

 be for ever disregarded. After due care has been observed in 

 collecting the milk, there come the process of curing. This also 

 requires the greatest care in order to yield the desired results. 

 The method employed by the Amazon workers is to dip a wooden 

 paddle (perfectly clean) into the milk can. A layer of sap then 

 adheres, and this is coagulated by the smoke from a vegetable 

 fibre. The paddle is repeatedly dipped, the object being to have 

 each layer as thin as possible so that the whole mass may be quickly 

 cured, thoroughly yet not excessively. This is necessitated by two 

 considerations : in the first place to ensure that all the sap is tho- 

 roughly coagulated, failing which the immature piece will lose in 

 washing from 5 to 20 per cent., and in the second and most vital 

 and important place, to secure the freedom of the gum from the 

 presence of rubber resins. 



Some eight years ago Professor HENRIQUE, of Germany, made 

 some investigations into the causes of the depreciation of the quality 

 of vulcanised India rubber under the influences of heat, time and 

 sunlight. The effects noted were — that some rubbers become hard, 

 brittle and rotten, whereas other rubbers under the same conditions 

 retain their old strength and vitality. The Professor traced the 

 cause of this to the presence of quantities of rubber resins in the 

 defective samples, and explained that the 5 per cent, of sulphur 

 originally introduced for the purpose of vulcanisation had formed 

 considerably traces of sulphuric acid in combination with the resins, 

 which in course of time had destroyed and rotted the rubber. This 

 fact, having been experimentally verified, led to the issue of an 

 order by Sir A. M. RENDEL, on behalf of the Indian State Railways 

 and of the Indian Government, limiting the percentage of rubber 

 resins in any manufactured articles to 5 per cent. This test has 

 been rapidly adopted by all Government Departments and has now 

 become the standard for all high class goods. Hence the manufac- 

 turer cannot afford to use any gum which does not meet this re- 

 quirement, for he cannot afford to run the risk of rejections. Thus 

 it becomes of the first importance to the rubber grower to see that 

 his product meet this requirement, or he will quickly find his article 

 relegated to the position of a third rate brand. Some experiments 

 have recently been made with a chemical treatment by alcoholic 



