Sept. 1906.] 



21S 



Saps and Exudations. 



MIXING. 



21. The masticated rubber is ready now to be mixed with the hundred and 

 one ingredients with which it is to be compounded. The requisite amount of 

 sulphur in fine powder is added, with zinc oxide, red lead, plumbago, asbestos, 

 powdered pumice, recovered rubber, rubber substitutes, rubber of other grades and 

 qualities, sulphide of antimony, lime, vermilion or any of all those substances which 

 the knowledge and experience of the manufacturer indicate as necessary for the 

 particular class of goods which the rubber is destined to become. This mixing is 

 done on rollers of exactly the same type as used in masticating, but the rolls are 

 kept cooler. The rubber is put on the machine and the ingredients sprinkled on 

 it as it passes through the rolls, they are folded between layers of the rubber, and, 

 after repeated working through the rollers, become thoroughly incorporated and 

 most intimately mixed into •'dough" of which each factory has many types and 

 the precise compositions of which are the secrets of each firm. The dough thus 

 compounded is rolled up and stored for future use. 



VULCANISATION. 



22. Vulcanisation is the name given to the act of combining India-rubber 

 and sulphur chemically into a new substance. There are two methods of producing 

 the desired result, known as the heat cure and cold cure, respectively. 



(To be Continued.) 



* ~ 



THE RUBBER BOOM. 



Whether you explore the wilds of the Cornhill or Leadenhall neighbourhoods, 

 or merely tour the less dangerous districts of agricultural fame in the tropics, you 

 will find that the rubber " boom " seems to be the pivot of commercial conversation- 

 And hearing the high talk of planters and company promoters, you will be 

 something more than human if you are not bitten with the desire for wealth 

 " beyond the dreams of avarice " which those who dwell in lands where the rubber 

 tree flourishes assure themselves is well within their grasp. 



A few days ago I returned from visits to Ceylon, Burmah, the Dutch Indies 

 and British Malaya, and in the Clubs of Colombo, Rangoon, Medan and Singapore 

 every one with a few dollars to invest proclaimed that there was " nothing like 

 rubber." In Ceylon the interest displayed in the boom amounted to a passion ; iu 

 the Federated Malay States the hotels and rest-houses were agog with option- 

 grabbers and "experts;" and on the very day I fouad myself back in the old 

 country the postman brought the prospectus of the Straits Settlements (Bertram) 

 Rubber Company, Limited, who have acquired a considerable (and costly) concession 

 on the hinterland of Penang. It is a world-wide boom indeed.— India Rubber Journal. 



