The alkalies, alkaline earths, salts of cadmium, manganese, nickel, and cobalt are alkaline to erythrosine. The oxygen salts of iron, aluminum, and chromium behave like free acids to this indicator. It is not suitable for the titration of organic acids ; and even oxalic acid cannot be used. Ammonia, however, may be titrated with it. Erythrosine may be used with fairly turbid waters and also with colored waters. In this respect it is much better than lacmoid or phenacetolin, both of which tend to give too high results with such waters.

THE prospectors who years ago followed the Columbia River on the Canadian side of the international boundary and discovered mineral-laden veins in what is known as the Rossland district, British Columbia, little