. Rubber hand stamps and the manipulation of rubber; a practical treatise on the manufacture of India rubber hand stamps, small articles of India rubber, the hektograph, special inks, cements, and allied subjects . Tree Tapped for India Rubber. around the tree and a collecting gutter is worked with it for a basis. « v, f The iuice is coagulated in a smoky fire. A dot-tomless jar is placed over the fire and some palmnuts are mixed with the fuel. The mould, which ,soften a canoe paddle, is smeared with clay to pre-vent adhesion and is then heated. A cup of ]uiceis poured over it, and after the e
. Rubber hand stamps and the manipulation of rubber; a practical treatise on the manufacture of India rubber hand stamps, small articles of India rubber, the hektograph, special inks, cements, and allied subjects . Tree Tapped for India Rubber. around the tree and a collecting gutter is worked with it for a basis. « v, f The iuice is coagulated in a smoky fire. A dot-tomless jar is placed over the fire and some palmnuts are mixed with the fuel. The mould, which ,soften a canoe paddle, is smeared with clay to pre-vent adhesion and is then heated. A cup of ]uiceis poured over it, and after the excess has droppedoff it is moved about rapidly over the smoke and 22 nUBBER HAND STAMP MAKING hot air which ascends from the mouth of the series of operations is repeated until the coat-ing is quite thick; it may be as much as five solidifying over night it is cut open and thepaddle or mould is removed. After a few days dry-. Indian Drying and Smoking India Rubber. ing it is sent to market. With all the heating,during which it sweats profusely, it still retainsfifteen per cent, of water. India rubber sap may be coagulated by an aqueoussolution of alum. The process has been tried inBrazil, and is used to a considerable extent in AND THE MANIPULATION OF BUB BEE. 23 Pernambuco. It was proposed by an investigatornamed Strauss, and the process is still called by hisname. One objection is that it gives a very wetproduct, and apparently one of inferior value to thesmoked gum. The feeling that India rubber suffers in the gath-ering has been so much felt that it has been re-cently suggested that if possible the uncoagulatedjuice should be exported to Europe there to beworked up from the beginning. CHAPTER III. PROPERTIES OF UKVULCANIZED AND VULCANIZEDIKDIA RUBBER. There are two broad divisions to which all varie-ties of india rubber can be assigned—nnvulcanizedand vulcanized rubber. Speaking with a certainamount
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