Take of finely-powdered litharge five pounds, and olive oil nine pounds. Boil them together over a gentle fire, constantly stirring, with the addition occasionally of a small quantity of warm water, until the compound has the consistence of plaster. Jahn boils this plaster for half an hour with an equal weight of water, keeping it at the same time constantly stirred. When cold, he pours off the supernatant fluid, and repeats the boiling three times at least with a fresh portion of water. The sweet fluids which result are mixed, and evaporated to six pounds, and sulphuretted hydrogen conducted through them as long as sulphuret of lead is precipitated. The liquid filtered from the sulphuret of lead is to be reduced to a thin syrupy consistence by evaporation. To remove the brown coloring matter, it must be treated with purified animal charcoal. However, this agent does not prevent the glycerine becoming slightly colored upon further evaporation. It possesses also still a slight smell and taste of lead plaster, which may be removed by diluting it with water, and by digestion with animal charcoal, and some fresh burnt-wood charcoal. After filtration, this liquid must be evaporated until it has acquired a specific gravity of 1.21, when it will be found to be free from smell, and of a pale yellow color. For the preparation of glycerine, distilled water is necessary, to prevent it being contaminated with the impurities of common water. Jahn obtained, by this method, from the above quantity of lead plaster, upwards of seven ounces of glycerine.--_Archives der Pharmacie_. * * * * * TEST FOR ALCOHOL IN ESSENTIAL OILS. J.J. Bernoulli recommends for this purpose acetate of potash. When to an ethereal oil, contaminated with alcohol, dry acetate of potash is added, this salt dissolves in the alcohol, and forms a solution from which the volatile oil separates. If the oil be free from alcohol, this salt remains dry therein.