100 



several different contractors, whose rubber has to be kept separate, 

 the sub-division of a tank into small compartments is very necessary 

 to ensure an even quantity and equal density of late^: in each, every 

 day. 



I have been experimenting with a small tank made to contain 

 40 gallons and have had good results from it. It is light enough to 

 go on a small trolley and be moved about by one cooly up to the 

 receiving tank, and back, when filled, to the most convenient place 

 for dealing with the coagulation. It is made of acid-proof concrete 

 and is 30" x 68" x 9" and makes 34 sheets. The only disadvantage 

 is that the sheets turn out too narrow for economy in rolling, and I 

 am having a deeper one made by the designers, Messrs. R. Young 

 and Co., Penang, to remedy this. The small tanks on wheels seem 

 to me to have many advantages over the large .tank on a fixed base. 



Kneading and Rolling. 

 When the coagulated sheet is taken out of the pans in the 

 morning it is placed on a smooth heavy chengai board, and coolies 

 tread it out till it is a firm mass, ready for the smooth roller. This 

 saves rolling more than is necessary and, I believe, retains the 

 strength in the finished sheet. Kneading by hand, or rolling out 

 with a rolling pin, takes longer to get the sheet tough enough to go 

 through a roller without tearing, unless the first rolling is done 

 with the rollers very far apart, and several subsequent rolls are 

 wanted. Coolies soon become experts at treading sheets out evenly, 

 and reduce the thickness to the desired limit quicker than machines 

 can, without tearing. The sheets then go once through a heavy 

 smooth roller set at about ^ of an inch, then through another, set 

 at -^ of an inch, and then through the marking roller set just 

 hard up enough to miss grinding. The setting of the last two rollers 

 is never altered, the adjusting keys being removed entirely so that 

 the coolies in charge have no option in the matter. This ensures 

 uniformity in thickness. The sheeting-machines are 18" x 7" and 

 have speed revolutions at the rate of 11 per minute for the smooth 

 roller and 9 per minute for the marking roller. The grooving on 

 the latter are spirals, | of an inch apart, to give a small diamond, and 

 the estate name is lettered round the centre of one I'oller, the spirals 

 stopping where the lettering begins, and there is a blank space 

 without spirals on the other roller exactly opposite. The main 

 points to be observed in rolling are that sheets must go through 

 evenly without a pull in any direction, and the lettering must be 

 kept equi-distant from the edges of the sheet. If the rollers are set 

 evenly the sheets will go through correctly without any guidance, if 

 started evenly. 



Economy in time is effected by having the sheets almost as 

 broad as the length of the rollers. It takes just as long for a sheet 

 80" x 9" to go through as for one 30" x 15", and the actual difference in 



