89 



component particle, even the molecule, is exposed to the action of 

 smoke and is so polymerised, and thus the keeping quality of the 

 resulting rubber is assured, and the subsequent vulcanizing test satis- 

 factory for years afterwards. 



30. It will be evident that the process differs from all others that 

 obtain, and it is asserted that perfect coagulation and curing of Hevea 

 latex can only be effected when the water within the latex is separated 

 and disposed of at the same time. Whatever the re-agent may be, 

 when Hevea latex is treated in volume, the process is one of coales- 

 cing (smoke applied to latex in volume furnishes the same result). In 

 volume the re-agent diffuses too slowly, and the particles of caout- 

 chouc flock into an agglutinated mass, leaving a residuum of caout- 

 chouc in the mother liquor. Such coalesced rubber not only oxidises 

 and moulds after preparation, but is also faulty in the vulcanizing 

 process. Smoke coagulated rubber on a belt, where the particles and 

 globules of caoutchouc are expanded, so that even the molecule is 

 exposed and polymerised, improves in keeping, while coalesced rub- 

 ber wliich has not been cured but merely agglutinated, deteriorates. 



31. The process differs too from the Brazilian method in the 

 application of dry filtered smoke as compared with the water vapour- 

 ish smoke used in Brazil. In Brazilian smoke the three elements of 

 Hydrogen, Oxygen and Carbon are excessively high, while other ele- 

 ments are only partially generated. The more material difference 

 however, lies in the separation of water by this process against its 

 absorption in the Brazilian one. 



32. Mention has already been made of vertical adjusting gear 

 to accommodate the sag of the belt as it becomes loaded, the weight 

 however, is in inverse ratio to the latex supplied, as owing to the 

 separation of water and caoutchouc there is considerable drip and 

 evaporation of muisture. 



23. It is estimated that a belt one foot wide would coagulate 

 7^ gallons of latex in 3 to 4 hours. Before removal from the belt 

 the rubber should be surface dry or slightly hardened for stripping. 

 It can then be readily removed and passed through rollers in the 

 same operation of stripping, when the remaining water is expressed 

 out, and complete drying is effected in a few days, if the rubber is 

 smoked daily, fc;r which purpose the smoke chamber could be 

 utilized. (A sample of such rubber analysed at the Imperial Institute 

 was reported to contain O.04 ' moisture and arrived in excellent 

 condition free from mould). On estates where there is washing 

 and preparing machinery the process would be considerably ex- 

 pedited if the belt w-as stripped at intervals, as the water separates 

 and evaporates quicker the less the belt is loaded. It is esti- 

 mated that a belt one foot wide and stripped at intervals would 

 coagulate from 4 or 5 gallons of latex per hour. An adjustable 

 rubber brush is attached to the driving gear which scrapes off the 

 freshly coagulated rubber and leaves the surface of the belt compa- 

 ratively dry. The rubber is brushed into a funnel and drops into a 



