GLYCERINE

is a sweet substance which may be extracted from fatty substances. If we take equal parts of olive oil, and finely-ground litharge, put them into a basin with a little water, set this on a sand bath moderately heated, and stir the mixture constantly, with the occasional addition of hot water to replace what is lost by evaporation, we shall obtain in a short time, a soap or plaster of lead. After having added more water to this, we remove the ve el from the fire, decant the liquor, filter it, pa sulphuretted hydrogen through it to separate the lead, then filter afresh, and concentrate the liquor as much as is po ible without burning upon the sand bath. What remains must be finally evaporated within the receiver of the air-pump. Glycerine thus prepared is a transparent liquid, without colour or smell, and of a syrupy consistence. It has a very sweet taste. Its specific gravity is 1·27 at the temperature of 60°. When thrown upon burning coals, it takes fire and burns like an oil. Water combines with it in almost all proportions; alcohol di olves it readily; nitric acid converts it into oxalic acid; and according to Vogel, sulphuric acid transforms it into sugar, in the same way as it does starch. Ferment or yeast does not affect it in any degree. Its constituents are, carbon 40; hydrogen 9; oxygen 51; in 100.