This mixture contains only about seven per cent of potash and would not prove profitable when used at a distance from the mines on account of the cost of freights. It has proved valuable, however, for a top dressing for meadow lands in the vicinity of Stassfurt. =244. Schönit.=—Among the Stassfurt deposits there occurs in small quantities a mineral, schönit, which is composed of the sulfates of potassium and magnesium. The quantity of the mineral occurring naturally is very small and therefore it has no commercial importance. When, however, kainit is washed with water the common salt and magnesium chlorid which it contains being more soluble are the first leached out, and the residue has approximately the composition of the pure mineral. This mixture, as prepared in the way mentioned above, has the following average composition: Potassium sulfate 50.40 per cent. Magnesium sulfate 34.00 “ Sodium chlorid 2.50 “ Water 11.60 “ The percentage of potash corresponding to the above composition is 27.2. This substance being so rich in potash, and practically free of chlorids, is well suited to transportation to great distances and for general use in the field. Since, however, a considerable expense attends the manufacture of the artificial schönit, the advantages above named give it very little, if any, advantage in competition with the other potash salts as they come from the mines. It has, however, an especial value for the fertilization of tobacco and vineyards. =245. Potassium Sulfate.=—Several grades of potassium sulfate are found in the market for fertilizing purposes, some of them quite pure, containing over ninety-seven per cent of the pure sulfate. The following data show the composition of a high grade and low grade potassium sulfate of commerce: High grade. Low grade. Potassium sulfate 97.20 per cent. 90.60 per cent. Potassium chlorid 0.30 “ 1.60 “ Magnesium sulfate 0.70 “ 2.70 “ Magnesium chlorid 0.40 “ 1.00 “ Sodium chlorid 0.20 “ 1.20 “ Insoluble 0.20 “ 0.30 “ Water 0.70 “ 2.20 “