317 



the Malav Peninsula owes to Mr, R.USSELL and the Federated En- 

 gineering Company for the time, trouble and money that was spent 

 in making a machine for exhibition — the first of its kind ever seen 

 in this part of the world — must not be overlooked. 



Without it words would have been weak, I fear futile, seeing is 

 and was believing. 



APPENDIX I. 

 The Rubber-Washing Machine. 



This machine consists essentially of two steel rollers which 

 revolve on horizontal axes parallel to one another., the distance 

 between the surfaces of the two rollers can be adjusted and varies 

 from \ inch to practical contact. 



The rollers revolve at different speeds and are driven by power 

 transmitted from belt and pulley, through gear wheels to the rollers 

 themselves. 



The axes of the two rollers may be on the same horizontal plane . 

 more usually one is slightly above the other, a stream of water 

 flows over the surfaces of the rollers all the time they are in use. 



When the machine is used, freshly coagulated lumps of rubber 

 are put between the rollers, which are separated about \ inch. The 

 rubber is passed through several times, the rollers being gradually 

 approximated to each other — -and the rubber becomes compacted 

 and to some degree hardened. At the same time the effect of the 

 differential rate of movement of the two roller surfaces is to subject 

 the rubber to a shearing stress, which stretches and tears it to 

 pieces, and it is here that the peculiar property of rubber is clearly 

 seen. The elastic stretching and rebound, kick out any gross 

 mechanical impurity that may be present, and when the machine 

 is used on scrap rubber there is a perfect shower of dirt, pieces of 

 bark and wood thrown out from the front of the machine. Freshly- 

 cut or torn surfaces of rubber re-unite on contact and pressure, 

 for this reason the fragments into which the rubber is torn by the 

 machine re-unite and emerge as a continuous sheet. At the same 

 time the stream of water thoroughly washes out any impurity 

 soluble in water that may be left in the rubber. The final product 

 is a coherent but granular sheet of -rubber, the thickness of which 

 can be regulated by the distance left between the rollers. The 

 function of the machine is thus threefold : — 



Firstly it ejects mechanically any solid impurity , 



Secondly it breaks up the rubber and subjects all portions of 

 the rubber to the washing effect of flowing water ; 



Thirdly it produces granular thin sheet of uniform thickness 

 which is clean and which can easily and rapidly be dried. 



