In preparing black carbon paper either of the two following compositions may be used, (a) Finest lampblack 5 parts, olive oil 5 parts, cerasin wax 1 part, and petroleum ether 10 parts, (b) Lampblack 5 parts, cerasin wax 6 parts, olive oil 5 parts, and petroleum ether 15 parts. The lampblack and oil are ground together in a mortar, transferred to a small dish or pan and slightly heated, and the cerasin wax added; when the latter has thoroughly melted, well stir the mixture, remove it to a safe place, and while still warm add the petroleum ether. For a bluish-black shade, add a little Prussian blue. The mixture, while wa-m, should be applied with a brush to paper that has been heated in an oven. After the application, lay the carbon paper on an old newspaper and return to the oven to allow the mixture to soa.k in. After about half an hour's heating any excess of fluid maybe removed with a cotton rag; the paper will be fit for use on cooling.