of the pure metal becomes exceedingly difficult, unless a very large excess of acid is used. No objection can be raised to the use of platinum foil for in making fifty grammes of cadmium chloride it cost less than a tenth of a milligramme and even this could probably have been avoided by using a somewhat larger amount of hydrochloric acid. The foil was always kept submerged in the acid liquid. The moist crystals of cadmium chloride were transferred to a combustion tube passing through an asbestus covered air-bath, and dried in a current of hydrochloric acid gas for several hours at 300°C. The hydrochloric acid gas had been passed through a long calcium chloride tube to dry it, although calcium chloride probably does not do this very thoroughly. The hydrochloric acid gas was then replaced by a current of nitrogen prepared as has already been described under the sulphide method. After the current of nitrogen had been passing for about half an hour, the tube was allowed to cool, and the chloride transferred to another combustion tube, one end of which had been sealed in the flame of a blast lamp. The other end was drawn out and attached to a Sprengel mercury pump. After exhausting, the chloride was sublimed in the vacuum. This takes place at a moderate temperature and the sublimate has a beautiful crystalline structure and is perfectly white. The crystalline mass exposes so much surface that water is taken up very rapidly when exposed to the air. This action is so rapid that the crystals cannot be transferred to a weighing-glass without introducing an appreciable error. The whole sample was accordingly transferred to a stoppered glass bottle which was kept under a bell jar with sticks of caustic potash. Three samples were prepared in this manner, the first being used in determination one, the second in determinations two to seven inclusive, and the third in determinations eight to nineteen inclusive. The samples used in determinations twenty and twenty-one were prepared in the following manner: About three grammes of cadmium were placed in a combustion tube in which three bridges (as in the distillation of pure cadmium) had been made. A section may be represented thus [Illustration]