132 PARA RUBBER. 



Smoked plantation rubber has been generally well reported 

 upon, and buyers state it appears stronger than the unsmoked 

 product. 



Such rubber is obviously only antisepticised superficially, and 

 consequently not sufficiently protected against the various agents 

 responsible for putrefaction, tackiness, &c. 



For this to be effectually performed it is necessary to follow 

 more closely the method adopted by the Amazonian collectors 

 and smoke the latex. An apparatus for this purpose has been 

 recently placed on the market (see Fig. 29). 



" This plant, which is the result of practical experiments and 

 tests by Mr Da Costa, and is made by Messrs David Bridge & 

 Co., the well-known rubber engineers of Castleton, Manchester, 

 needs no chemicals whatsoever, so long as tropical forest woods 

 are available for heating the boiler, as well as green foliage of 

 palms 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 being as 

 follows : 



" The latex, being brought from the field, is strained if it is 

 found to contain mechanical impurities, and then poured into 

 the coagulating tanks. Steam is meanwhile being raised to 

 about 30 to 35 Ibs. in the boiler, forest woods alone being used 

 for fuel. On to the burning wood in the furnace are then thrown 

 green palm leaves, nuts, or any green twigs of tropical trees, the 

 distillation of v\ hich produce 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 

 cleared of cinders, &c., and are then forced into the coagulating 

 tanks by a steam injector. 



"The force of the steam violently agitates the latex, and 

 during this operation every particle of it is reached by the smoke. 

 In about ten minutes, or rather more if the quantities to be dealt 

 with are very large, the caoutchouc globules coagulate and 

 separate from the lyes and rise to the surface. 



" The coagulated substance, after being allowed to cool off in 

 the tanks, is afterwards taken to a small press and turned out 

 in the shape of flat block rubber. These, in their turn, are then 

 re-blocked into cube form, and after being dried, either in a 



