OCR Text |
Show Effect of Copper fialti on India Rubber. In a recent paper Mr. W. Thomson, of Manchester, Enirland, said that it is known that copper salts have a most injurious in-jurious effect on india rnbber, and as copper is sometimes used in dyeing blacks and other colors cloth so dyed is liable to decompose,, and harden the rubber rub-ber put into it, A peculiarity investigated investi-gated by the authot is that metallic copper cop-per placed in contact with thin sheets of india rnbber brings oxidation SffnotfTT-ening SffnotfTT-ening of its substance, although no appreciable ap-preciable quantity of copper enters the india rubber, while metallic zino and silver have no injurious effect. All oils, except castor oil, have a most i detrimental effect on india rubber, which can best be kept under water, under un-der glycerine, in coal gas or in a vacuum. Tho smell of india rubber is one of the characteristics of its decomposition, and it has been noticed th.".t a piece of blotting blot-ting paper placed over the decaying rubber rub-ber is colored by certain volatile substances sub-stances resulting from the oxidation that produces tho hardening. Boston j Transcript. ! |