In this paper, it is proposed to outline a method for the determination of melting points of those metals and alloys having high fusion temperatures. The application of the method as used to determine the melting points of alloys of tungsten and molybdenum will be given. It will be seen from these results that tungsten and molybdenum form a completely isomorphous series. This is also verified by the accompanying photomicrographs.
Tungsten and molybdenum have been found to crystallize in the same system, namely, isometric, and the crystal units are cubes. These determinations were made by examining etching pits in the pure metals.
Fig. 1 shows a partial section of the apparatus used for determining the melting points of the alloys. W1 is a water-jacketed metal housing with a mercury seal m2 at the bottom, h1 is a hydrogen inlet and h2 a hydrogen outlet, c1 is the top electrode which is water-cooled, as indicated by W2. This electrode is supported by the post p, to which it is fastened by means of an adjustable sleeve. C2 is the bottom electrode which floats in a bath of mercury m1. This mercury is contained in the casting k, which is