In a paper1 collating recent values of the compressibilities of the elements, the periodic nature of compressibility was emphasized, especially in relation to the similar periodicity of other properties. In this connection, the values of these constants for indium and gallium are particularly interesting because of the low melting points of these substances. The compressibility of gallium has already been determined;2 that of indium is recorded in the present paper. The sample of metal used in

more »

... he following determinations had been carefully purified, having been recovered by suitable electrolytic means from the amalgams used in an earlier electrochemical re~earch.~ It was cast in the shape of a cylindrical bar by slowly cooling liquid indium in an appropriate glass tube which had been coated with an exceedingly thin film of soft paraffin to prevent the adhesion of the metal to the glass. After cooling, the tube was broken and the ingot was removed, freed from traces of oxide and imperfections in casting at the upper end by cutting with a clean knife, and thoroughly cleansed from paraffin. The metallic rod thus obtained was 4 ~ 5 cm. long and 0.5 I cm. in diameter and weighed about 6.7 g. The density of this bar was measured, in order to be sure that it contained no air cavities, by weighing first in air and then in water, suspended by a very thin wire, for which due allowance was made in the calculation. Two determinations gave the following results a t room temperature