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simpler methods, and it is only the incident of rain upsetting the 

 normal state of things, and the vaiying rubber content of latex 

 during the wintering months that call for a reading of the instru- 

 ment. These methods are perhaps crude, but they are practical and 

 suited to the intelligence of the factory cooly, and the results have 

 been consistently good. Where tapping is done by coolies on daily 

 wage entirely, bulking the whole of the estate's latex is of course the 

 surest method of ensuring standardization. 



Coagulation. 

 Having bulked our lat«x and cup-washings the next step is to 

 add the acid necessary for coagulation. This is done before the 

 latex is put out into pans and a stock solution is kept i"eady in air- 

 tight jars. The solution is made up of 12 oz. acetic acid and | lb. 

 sodium bisulphite to one gallon of water — one gallon of this being 

 sufficient for 80 gallons of latex and cup washings. I have tried 

 sulphuric acid on a small scale, but was not very successful with it, 

 and did not continue experiments, the main reason being that we 

 had buyers who relied on uniformity from the estate, and the 

 change of acid might have upset previous vulcanization tests and lost 

 the confidence of the buyers. Pans thoroughly washed are stacked 

 at hand to receive the latex, each containing j of a gallon of 

 water and one gallon of latex is poured into each pan with as little 

 delay as possible after the solution has been thoroughly stiired 

 into the bulk. Skimming is done at once with a strip of tin 

 almost as broad as the pan and the pans are placed on shelves 

 in cupboards screened all round by a drop-curtain of tui"key-i«d 

 cloth. The pans used are 16" x 10" x 4' and produce a dry 

 sheet 25'' x 11" in the case of latex fi*om old trees and one 

 slightly smaller fix)m young rubber. Coagulation is usually finished 

 by 12.30 p.m. and this allows for latex being brought in carts from 

 outlying fields two miles from the factory. The pans are left 

 untouched overnight. The reason for the added water not being 

 put into the bulked latex is that 1 found bubbles restdted from 

 bad fusion of water and latex owing to insufficient stirring by coolies 

 when not watched, sheets from the same jar or tank varying 

 considerably. The method used leaves nothing to chance and is 

 therefore preferable. There is also economy in the number of jars 

 or tanks required for containing the bulk of latex before it is 

 put out into pans. In tank coagulation the solution of acid is 

 put into the latex after it has settled in the tanks and before 

 the partitions are placed in their slots. The majority of tanks 

 I have seen do not give such good results as pans owing principally 

 to the fact that the partition laths are not perfectly water tight and 

 permit latex to ooze through from one division to another causing a 

 i^agged edge on each sheet which is difficult to get rid of. Most 

 of them are also too big, without enough divisions to deal with 

 the ever vaiying gallonage. When an estate has tapping done by 



