MACHINERY AND MANUFACTURE 



201 



there also, which have the effect of weakening its strength. 

 The flour dough out of which Scotch bread is made is worked 

 up much more than the dough for English bread. The effect 

 is that Scotch bread is of a whiter colour but of slightly sub- 

 acid flavour. Working up too much almost any sort of dough, 

 or straining too often any metal, has an effect in some direction 

 or another. 



Some authorities take the view that the rubber is just a 

 gum and that the working in the mills has no more effect on its 

 constitution than stirring a gum-pot would have on the gum. 

 This, however, is wrong. It is one thing to stir the gum in a 

 pot slowly by hand 

 and quite another to 

 churn it rapidly with 

 machinery. When the 

 latex is coagulated it 

 may not have ceased 

 to be a gum, but it is 

 a manufactured gum 

 with altered ingredi- 

 ents incorporated in it 

 and changed proper- 

 ties. The conditions 

 are therefore entirely 

 altered. 



Throughout this 

 chapter illustrations 

 of various standard types of washing-mills by leading firms 

 of engineers are interspersed. All these firms make excellent 

 machinery. All have their machines working on various 

 plantations, and it is rare to hear of any expressions of dis- 

 satisfaction. For this reason no special make is singled out 

 for higher commendation than what is equally bestowed on 

 the others. 



The type of mill most popular in Ceylon is, curiously enough, 

 not that which specially commends itself to up-to-date planters 

 elsewhere. Ceylon planters go in for belt-driven mills, while 

 in the Federated Malay States, the Straits Settlements and in 

 Sumatra the mills are driven by machine-cut gearing and 

 friction-clutch direct from the main-line shafting at the back 



FIG. 56. A Battery of Mills Direct Drive 

 ( Bridge & Co.). 



