Some measurements of isothermal compressibility by a capacitance method

The compressibility of some alkali halides has been measured by a fairly direct method involving a capacitance change. In order to see whether the large spread in compressibilities reported in the literature might be due to an unexpectedly large impurity effect, measurements were made on several samples of potassium chloride of differing purity; however no large impurity effect was found. A by-product of the investigations was the measurement of the variation with pressure of the dielectric constant of a hydrocarbon oil, and this showed unusual features.