Thermostatic bath INDEX

To determine the refractive index of a liquid at 20 °C, water from a thermostatic bath is circulated through the jacket which surrounds the two prisms, until the temperature on the thermometer of the instrument has remained steady for at least 10 minutes. The hinged prism is unclamped and both prism surfaces are wiped carefully with paper tissue suitable for optical surfaces. An appropriate amount of liquid (usually only a drop) is applied to one prism surface and the prisms reclamped. The field of view through the telescope is observed and the control knob adjusted so that coincidence of the borderline between the light... 

HPLC was performed with a liquid chromatograph (Waters Associates Series 6000) equipped with UV and refractive-index detectors. Asphaltene fractions were examined by using a 25- X 0.5-cm column packed with silica gel and maintained at 25 °C by an external thermostatically controlled water bath. Asphaltenes and standard polynuclear aromatic compounds were passed through the column with chloroform-isopropyl alcohol blends (90 10). 

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