and Magazine of the Ceylon Agricultural Society. 



81 



SMOGCED RUBBER. 



DA COSTA'S PATENT RUBBER COAGU- 

 LATING PLANT. 



Whatever may be the differences of opinion 

 between Manufacturers as to the value of the 

 different species of Crude Rubber available in 

 the world's Markets, they are certainly unani- 

 mous in pronouncing the product of the Para 

 Rubber Tree, as prepared by the natives, to be 

 the best of all species of Rubber. The native 

 process of smoking the latex of the Hevca Bra- 

 siliensis (Para Rubber) in the. Amazon region is 

 only persisted in because no other process has 

 met with the approval of Manufacturers. 



Shett and Crepe Rubber were manufactured 

 in Brazil long before the Rubber industry was 

 thought of in the East Indies, but it had to be 

 abandoned because of the manufacturers' pre- 

 ference for the native smoked product. 



Every chemical ingredient now used in the 

 East Indies to preserve the Rubber or assist in 

 the coagulation, has been tried again and again 

 and, in every instance, whore the assistance of 

 chemicals has been resorted to, an article of 

 good appearance has been produced, but always 

 inferior to the smoked Rubber when tested by 

 the manufacturers' standard. The fact is that 

 any chemical agent, of whatever nature, intro- 

 duced into the latex of the Para Tree in a liquid 

 or palpable form, injures the resiliency of the 

 Rubber produced, as repeated trials have clearly 

 demonstrated. 



The real cause of this continues to be one of 

 nature's mysteries, but it is an undoubted fact. 

 Whilst it is known by long experience on the 

 Brazilian forests, that heat will coagulate the 

 latex from the Para Tree, it is also beyond 

 doubt that fumigation alone will impart to the 

 finished product its lasting properties of re" 

 siliency and tensile strength that have made 

 the products of the Hevea Brasiliensis famous 

 all the world over. So too, as regards the 

 latex of the Castilloa Elastica tree, nothing but 

 very fierce heat will kill the enzymes it contains 

 and unless these are destroyed the Rubber pro- 

 duced therefrom will always be jet black and 

 more or less tacky, if kept for any length of time. 



On the face of these facts, and because the 

 method of smoking latex by the native process 

 in Brazil is not only very expensive and ex- 

 ceedingly tedious, but also certainly detrimen- 

 tal to the health of the operators, the inventor 

 of this plant thought of dovising means of 



DOING MECHANICALLY 



all that is now done by hand in the Rubber 

 forests of Brazil. The Da Costa Patent Coagu- 

 lating Plant which is the result of practical ex- 

 periments and tests, and is now manufactured 

 solely by Messrs. David Bridge and Co., En- 

 gineers and Rubber Machinists, Castleton, 

 Manchester, England, for whom Messrs. Zach- 

 arias & Co. of Kuala Lumpur are acting 

 as sole agents in the Malay Peninsula, 

 needs no chemicals of whatsoever nature, sc long 

 as tropical forest woods are available for heat- 

 ing the boiler as well as green foliage of palms 

 of any sort for generating smoke in the boiler 

 furnace. The coagulating and smoking by means 

 of this plant is the simplest of all operations 

 in the Rubber Industry and may be performed 

 by any inexperienced hand. The process is as 

 follows: — The latex being brought from the field 

 is strained only provided it contains mechanical 

 impurities and is then poured into the coagu- 

 lating tanks. Steam is meanwhile being raised 

 to about 30 to 35 lb. per square inch in the 

 boiler, forest woods alone being used for this 

 purpose. On the burning wood in the boiler fur- 

 nace are then thrown green Palm leaves, nuts, 

 or any green twigs of tropical trees ; the dis- 

 tillation of the woods producing acetic acid, 

 whilst the fumes of the green foliage would be 

 found to contain creosote to some extent. These 

 fumes are accumulated in a special receptacle, 

 after being expunged of all cinders and are then 

 forced into the coagulating tanks by a steam in- 

 jector. The force of the steam violently agitates 

 the latex and during this operation every par- 

 ticle of it is reached by the smoke. In about 

 ten minutes (more if the quantities to be dealt 

 with are large) the whole mass coagulates 

 and separates from the lyes and floats in 

 the water caused by the condensation of 

 the steam injected into the tanks. The 

 coagulated substance is allowed to cool off 

 in the tanks, and must afterwards be taken to 

 a small press and blocks are then reblocked in 

 cube form and afterwards dried either in a special 

 stove or vacuum dryer. If the first size blocks 

 are only lightly compressed into the form of 

 cubes, they can be easily torn as under by the 

 manufacturers and used in their machines 

 without the extra labour of previously cutting 

 them into convenient sizes. 



QUALITY OF THE RUBBER PREPARED. 



Rubber prepared in this way retains every 

 nativo clement of the resiliency and tensile 



