Abstract: Disclosed herein is a high-sensitivity differential refractometer which is characterized by having a light source disposed outside a housing, a reflecting mirror attached at the end portion thereof to a reflecting mirror-supporting plate connected with the end of a movable plate, said movable plate being so constructed as to rotate around a vertical axis and permit free change of the angle formed between said reflecting mirror-supporting plate and the movable plate, a twisting member disposed inside a lead-in tube and said lead-in tube fastened to a removable case and built in a metallic block inside the housing.

Abstract: An improved apparatus for protection of a liquid chromatography column is proposed. Under environmental changes in pressure and temperature, a liquid and a gas in a non-expandable container communicated with the chromatography column change their relative volume, so that the environmental changes are not transmitted to the column. To prevent the gas from entering into the column, a conduit connecting the column and the container enters into interior of the container.

Abstract: The coefficient of thermal conductivity of any sample can be measured without any pre-processing to the sample by putting an electric heater and a thermo-electric couple between a block made of reference material whose coefficient of thermal conductivity is known and the sample, flowing electric current in said heater, measuring the temperature of said heater with said thermo-couple, and calculating the coefficient of thermal conductivity of the sample according to the measured data. The present inventors introduce herein a novel equation for that calculation.