CHAPTER XI. 



THE PRODUCTION OF RUBBER FROM LATEX. 



Production of rubber by natural coagulation — Production on a small 

 scale illustrated — Suggestions for curing rooms — Effect of heat 

 and chemicals on coagulation — Smoking and coagulation — The che- 

 mistry of the Amazon method — Coagulation by chemical reagents — 

 Acetic acid — Formic acid — Hydrofluoric acid — Tannic acid — Corrosive 

 sublimate — Amount of acid to be used — Determination of complete- 

 ness of coagulation — A method of determining the amount of acetic 

 acid required — Advantages and disadvantages of adding chemicals to 

 the latex — Value of acids and preservatives discussed — Components of 

 coagulated rubber — Amount of proteid in mother liquor and rubber 

 — Putrefaction of rubber — Analyses of sound and tacky rubber — 

 Keeping the proteid inactive — Antiseptics, drying, dilution, and 

 washing — The removal of the proteid from the latex — Formalin and 

 sodium sulphate — Rapid coagulation and removal of proteids by 

 mechanical means — Biff en's centrifugal machine — Experiments in 

 Ceylon with the Aktiebolaget Separator — Principles of mechanical 

 separation — Rapid coagulation by mechanical and other means — 

 The Michie-Golledge machine; construction, action, and illustration 

 — Mathieu's apparatus. 



HAVING briefly described the physical and chemical properties of 

 the latex as it is obtained in the field, it now remains for us to 

 consider the operations upon which the production of good rubber from 

 latex depends. If the pure latex is allowed to stand in a receptacle, it 

 finally coagulates and the caoutchouc globules with other substances 

 float to the top, leaving a more or less clear liquid behind. 



By the addition of chemical reagents or by subjecting the latex to 

 different temperatures coagulation may be hastened or retarded. 

 The coagulated substance after washing, pressing, and drying is 

 ultimately known as the rubber of commerce. 



In the production of rubber from latex the planter may either 

 take advantage of the presence of coagulable constituents in the latex 

 or adopt chemical and mechanical means for the separation of the 

 caoutchouc globules from the rest of the latex. 



Production of Rubber by Natural Coagulation. 



This change is due to the presence, in solution, of albuminous oj 

 proteid matter, which quickly coagulates or becomes insoluble. The 

 coagulated proteid carries witli it the suspended globules of caout- 

 chouc and other bodies, so that the whole process is more or less one 



