Chrome Ironore, or Chromite

(Chem.) An important ore of chromine, from which are obtained the salts of chromine used in commerce. The mineral, which consists of protoxide of iron and sesquioxide of chromium, is reduced to powder, fused in a reverberatory furnace with half its weight of nitre, and stirred continually. In this manner the chromium is converted into chromate of potash. The ma is di olved out with hot water, and the silica and alumina are precipitated by some strong acid, which at the same time converts the neutral chromate into the acid bichromate. Chrome/-green, n . ( Painting .) A compound dark green pigment of which chrome-yellow is the principal coloring substance Chrome'-orange, n . ( Painting .) Dichromate of lead, which is of a splendid orange color, is obtained by adding to a solution of nitrate of lead a solution of chromate of potash, to which an equivalent of hydrate of potash has been added. It is obtained of a still more brilliant color by fusing together five parts of nitre and one part of chromate of lead. Chromate of potash and dichromate of lead are formed, and the former salt is removed by washing.