I. On the optical properties of a new chromic oxalate

With the view of making a series of spectroscopic observations on coloured salts, I have lately prepared many salts of chromium, and have been successful in obtaining some interesting new substances, one of which is remarkable alike in its chemical constitution, its fine crystalline character, and its optical properties. It has the formula KCa″} 3C2 O4 . 4H2 O, Cr‴ and must therefore be calledpotassio-calcium chromic oxalate .Preparation .—a . By mixing the blue potassium chromic oxalate with calcium chloride: the solutions should be dilute and warm. The salt is deposited in crystals.