INDIA-RUBBER.
India-rubber or Caoutchouc which was, a short time back, used only for the very insignificant purpose of rubbing out pencil marks, is now used for almost innumerable purposes. India-rubber is the solidified juice of several trees, such as the Siphonia, Jatropha Elastica, Ficus Elastica, &c., the juice is got by making incisions in the trunk of the trees during winter and collecting the juice, which is caoutchouc combined with water, in the form of a milky thick fluid, the water is then allowed to evaporate and the India-rubber remains. It is brought here in all sorts of shapes, and is purified before it is fit for commercial use by washing in warm water or steaming; it is then cut into pieces and put into a kneading machine which cuts and works it together with such rapidity that it becomes quite hot and the pieces join into one mass. After having undergone every kind of torture that can be well imagined in the form of cutting, tearing, and squeezing, it is finally compressed in a square cast iron mould, where it is kept for a time, and then is fit for any use it has to be applied to. What is called vulcanized India-rubber is produced by incorporating it with powdered sulphur, or some substance containing it, as sulphuret of antimony, or the vapour of sulphur is kneaded into the mass; this vulcanized rubber is very elastic and does not harden by cold. Waterproof fabrics are made by stretching the stuff to be waterproofed on a frame, at one end of which is a partition having a slit in it, through which it is drawn, after having been smeared with a solution of India-rubber in naptha; the slit is so narrow that it scrapes off all superfluous caoutchouc, it is then dried in the air.