A French .paper states that a new prap« aration for the purpose of replacing india rubber and gutta-percha has been brought out and protected by M. M. Worm 3 ancc Zwierchowski' To a quantity of Manilla gum tempered with benzine is added 5 pef cent, of Auvergne bitumen, also mixec? with benzine.' These are thoroughly mixed together by mechanical means and by tha hand. By adding 5 per cent, of rosin oH, and allowing forty-eight to eighty-six hour* to pass between' each treatment, a product is obtained having all the suppleness, elas ticity, solidity and durability of the besli india rubber. If the product is too fluid, the addition of 4 per cent, of sulphur dissolved by means of sulphate of carbon will remedy this: The addition of 5 per cent, of india* rubber to this mixture makes an irre proachable compound for certain purposes. The-vulcanisation of this product can be carried out in the usual way.
Familiar Science.
