The method described by Frühling as much used in the German laboratories, consists in igniting ten grams of the fine earth, previously dried at 140° in a crucible placed obliquely on its support and with the cover so adjusted over its mouth as to give a draft within the body of the crucible. The ignition, at a gentle heat is continued until on stirring with a platinum wire no evidence of unconsumed carbon is found. The moistening with solution of ammonium carbonate, should not take place until the contents of the crucible are cool. Subsequent ignition, at a low heat for a short time, will remove the excess of ammonium salt. =301. Method of Berthelot and André.=[194]—The earth dried at 110° contains still a greater or less quantity of combined water. This is the water united with alumina, silica and certain salts, but not the water of constitution belonging to organic bodies. The exact estimation of this water offers many difficulties. The determination of loss obtained at a red heat embraces: (1) The water combined with zeolitic silicates, with alumina and with organic compounds. (2) The water produced by the combustion of the organic compounds. (3) The carbon dioxid resulting from the partial decomposition of the calcium and magnesium carbonates. (4) The carbon burned and the nitrogen lost during ignition. The measure of the loss of weight in an earth heated to redness in contact with the air is not therefore, an exact process of estimating water or even volatile matters.