Phosphotungstic acid, H3PW12O#, has been reduced by t'-propyl alcohol under the influence of sunlight to a black product which precipitated silver from silver nitrate solution, while undergoing oxidation to the starting material. One molecule of HaPWiiOw after reduction precipitated one atom of silver from solution. Thus the reduced acid was in a state of oxidation equivalent to HjPWiaO»).

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Rhodamine B cyanide (III) has been prepared and found to have a remarkably reactive nitrile group in strong contrast to the behavior of the familiar triphenylmethane dye cyanides, such as I. In aqueous solution rhodamine B cyanide rapidly reverts at room temperature to the parent dye (II) and sodium cyanide. In dilute mineral acid the nitrile group hydrolyzes at room temperature to the carboxylic acid (V). Photolysis of rhodamine B cyanide (III) may yield not only rhodamine B (II) but also cornflower blue (VII). The carboxylic acid (V) is both photosensitive and a strong reducing agent, being readily oxidized to carbon dioxide and rhodamine B.

1211 solves in ammonium hydroxide to give the intensely blue solution characteristic of cupri-ammonium ion. The writer has found, however, that when dilute ammonium hydroxide is slowly added to precipitated copper ferrocyanide, and the mixture shaken after each addition, the mahogany-brown precipitate is completely converted to a silky, dark brown solid, probably a substance of the formula Cu2Fe (CN) 6.4NH¡¡.s This precipitate does not dissolve in coned, ammonium hydroxide, and is only slowly changed to copper sulfide when treated with hydrogen sulfide. Acetic acid, however, restores the copper ferrocyanide.Scott3 also states that the ferrocyanide of copper is soluble in ammonium hydroxide, and hence its presence must be avoided in the detection of traces of copper by the ferrocyanide method. When to two exceedingly dilute solutions of cupric sulfate, only one of which contained a trace of free ammonia, potassium ferrocyanide was added, the one without the trace of ammonia showed the usual characteristic deep red color, but the other developed a light brown color from which the silky, brown precipitate noted above settled on standing. These results could be duplicated as often as desired. They are to be interpreted as indicating that even the slightest trace of ammonia will seriously impair, if not completely obscure, the delicacy (1 part in 2,500,000) of the ferrocyanide test.Contribution from E.