Analysis showed this substance to contain 35.05 per cent, caesium, 37.0 per cent, of bismuth, and 27.8 per cent of chlorine. The compound is therefore 2BiCl33CsCl, which has been described by Brigham3. In a similar manner bromine was added to a hot solution of caesium tribromide and bismuth tribromide in hydrobromic acid. In this experiment a finely divided yellow precipitate was obtained which was quite insoluble in hydrobromic acid, but readily soluble in hydrochloric and nitric acids. Analysis showed this to be a new salt corresponding to the formula 2BiBr33CsBr, as it contained 46.9 per cent, bromine, 27.0 per cent, caesium, while the theoretical for 2BiBr33CsBr is 46.8 per cent, bromine, 27.1 per cent, bismuth, and 26.1 per cent, caesium.It is evident from the preceding work and from the experiments of others that while bismuth can exist in a higher state of valence than three with oxygen, thus far the halogens have not been combined with bismuth in any higher ratio than that of the valence of three.