When the work was repeated after the addition of 400 milligrams of calcium oxid the weight of the precipitate recovered was 62.3 and 63.1 milligrams in duplicate determinations. Similar determinations were made with a known weight, _viz._, 35.6 milligrams of alumina. The treatment of the mixture was precisely as indicated above for iron. The quantity of alumina finally obtained was 28.9 and 29.3 milligrams, respectively, in duplicate determinations. When the lime was added, however, the weights of alumina, recovered, fell to 19.8 and 20.6 milligrams, respectively. These results show that the molybdate method for the separation of iron and alumina in the presence of a large excess of lime and phosphoric acid is subject to widely varying results, but that the error due to the excess of iron in the weighed product is partly corrected by the one due to deficiency of alumina. =42. Method of Wyatt.=—A method largely used in this country, both in private laboratories and by fertilizer factories, for determining iron and alumina, is described by Wyatt[33]. It is claimed for this method that, while it may not be strictly accurate, yet it is rapid and easy, and in the hands of trained analysts yields concordant results. Fifty cubic centimeters of the first solution of the sample in aqua regia, or an amount thereof equivalent to one gram of the phosphate, in a beaker, are rendered alkaline by ammonia. The resulting precipitate is first redissolved by hydrochloric acid, and a slight alkalinity is again produced with ammonia. Fifty cubic centimeters of strong acetic acid are next added, the mixture stirred and placed in a cool place and left until cold. The precipitate is then separated by filtration and washed twice with boiling water. The vessel holding the filtrate is replaced by the beaker in which the precipitation was made. The precipitate is dissolved in a little fifty per cent hot hydrochloric acid and the filter washed with hot water. After rendering slightly alkaline, as in the first instance, the treatment with acetic acid is repeated as described. The precipitate is washed this time, twice with cold water containing a little acetic acid and three times with hot water. The precipitate is dried, ignited, and weighed as iron and aluminum phosphate. Half of this weight may be taken to represent the quantity of iron and aluminum oxids. To separate the iron and alumina the precipitate just described is dissolved in hot hydrochloric acid, filtered into a 100 cubic centimeter flask, and made up to the mark by hot wash-water.