New Method for Determining Compressibility

New Method For Determining Compressibility by Theodore William Richards and Wilfred Newsome Stull. This early 20th-century Carnegie Institution publication introduces a novel method for measuring the compressibility of liquids and solids. Richards, a Professor of Chemistry at Harvard University, and his assistant Stull describe an experimental apparatus that encloses most of the test liquid in a thin glass bulb surrounded by mercury to maintain constant temperature and to register small volume changes under pressure. They calibrate their measurements against mercury as a reference and carefully account for the compressibilities of mercury and glass themselves. The work provides detailed data for substances including bromine, iodine, chloroform, carbon tetrachloride, bromoform, phosphorus, and water, across pressures from near atmospheric to several hundred atmospheres, illustrating that compressibility generally decreases with pressure and varies among substances. The paper also outlines new methods for determining compressibility in solids and liquids, discusses a proposed high-pressure unit (megabar), and emphasizes precise instrumentation and calibration to establish reliable reference data in physicochemical research.