467 



increase in power in doing what, with washed rubber, can be done 

 in a more simple, safe and natural manner. 



MANUFACTURE OF RUBBER. 



16. Preliminary PROCESSES.-The various processes through 

 which raw rubber passes in conversion to rubber goods were as a 

 whole very freely shown to me by the British rubber manufacturer. 

 Introductions to the leading firms from the War Office and 

 Admiralty, who are large consumers of rubber goods, were obtained 

 through the Colonial Office, and these, together with sundry 

 personal and private introductions, proved to be all that was 

 necessary, and I met with great consideration, kindness and 

 courtesy from all with whom I came into contact. In a few cases 

 there were special and particular processes which were guarded as 

 trade secrets, but this tendency to secrecy was in inverse pro- 

 portion to the size and importance of the works. The greatest 

 interest was shown in plantation rubber and the prospect of a future 

 easing of the rubber market by supplies from the East, and the 

 manufacturers realise that there can be no antagonism between 

 them and the planters, and appreciate the efforts being made to 

 bring the producer and consumer into closer touch. 



17. The raw rubber used is of all kinds and qualities, from clean 

 pure fine Para to the lowest grades of African rubbers, which are 

 sticky, black, full of wood, stones and dirt, and all possible 

 adulterations. Fine Para is delivered in balls weighing from five 

 or six to a hundred pounds : when cut open the mass is seen to be 

 made up of concentric shells from i to J inch in thickness, the 

 rubber is grey and wet and the successive laminae are marked by 

 dark surfaces, showing the stages of successive smoking and 

 accumulation of the rubber into the balls. This rubber is never 

 dry, but contains water— the amount usually being about 15 per 

 cent., but varying from 10 to 20 per cent., and the loss of weight of 

 fine Para in washing and drying is due to this water contained in 

 it. In the best qualities there is little or no mechanical impurity, 

 at most a little surface dirt and grit. 



WASHING RAW RUBBER. 



18. The first thing to be done is to cut these large balls open 

 and reduce the largest masses to blocks of five to ten pounds in 

 weight. The rubber is then softened by boiling in water, this is 

 done to enable the washing machines to deal with the lumps. 



The rubber is then broken and washed on machines which are 

 simple in construction and action, and exactly similar in essentials 

 to the rubber-washing machines in use in the Malay Peninsula on 

 plantations. 



Each machine consists of a pair of steel rollers with roughen ■ 

 ed faces, revolving at different speeds on horizontal axes, the faces 

 of the rollers being in contact or slightly separated from one 

 another. The rollers are from one to two feet in length, and 

 usuallv one foot in diameter. The surfaces are roughened with 

 grooves cut spirally, or diamond shaped, and of different angles 



