To avoid this inconvenience, the author proposes a preliminary treatment of the manure with sulphuric acid at 1.845 sp. gr., to convert potassium nitrate and chloride into the fixed sulphate. The sulphuric acid attacks the manure energetically, and much facilitates the incineration, which may be effected at a dark red heat. The ignited portion (10 grms.) is exhausted with boiling distilled water acidulated with hydrochloric acid, and the filtrate, when cold, is made up to 500 c. c. Of this solution 50 c c., representing 1 grm. of the sample, are taken, and, after being heated until close upon ebullition, baryta-water is added until a strong alkaline reaction is obtained. The sulphuric and phosphoric acids, alumina, magnesia, etc, are thus precipitated. The filtrate is heated to a boil, and mixed with ammonia and ammonium carbonate, to precipitate the excess of baryta in solution. The last traces of lime are eliminated by means of a few drops of ammonium oxalate. The filtrate is evaporated down on the water-bath, and the ammoniacal salts are expelled by carefully raising the temperature to dull redness. After having taken up the residue in distilled water it is treated with platinum chloride, and the potassium chloro-platinate obtained is reduced with oxalic acid. The quantity of potassa present in the manure can be calculated from the weight of platinum obtained.--_Bull. de la Soc. Chim. de Paris_. * * * * * THE ORIGIN AND RELATIONS OF THE CARBON MINERALS. [Footnote: Read before the New York Academy of Sciences, February 6, 1882.] By J.S. NEWBERRY. What are called the carbon minerals--peat, lignite, coal, graphite, asphalt, petroleum, etc.--are, properly speaking, not minerals at all, as they are organic substances, and have no definite chemical composition or crystalline forms. They are, in fact, chiefly the products or phases of a progressive and inevitable change in plant-tissue, which, like all organic matter, is an unstable compound and destined to decomposition.