Abbe refractometer, Zeiss Model I
Date: circa 1915
Inventory Number: 1992-1-0001
Classification: Refractometer
Dimensions:refractometer: 29.5 × 14 × 14.5 cm (11 5/8 × 5 1/2 × 5 11/16 in.)
case: 36 x 21.5 x 16.8 cm (14 3/16 x 8 7/16 x 6 5/8 in.)
Accessories: wood case; empty bottle for monobromnaphtalin; calibration glass plate ("Justierplättchen") of N/d = 1.5176; thermometer with scales "B" and "S"
Bibliography:Optical Measuring Instruments. Part I
Description:
A circular base supports, on a fixed vertical column, an Abbe double prism that can be heated with circulating warm water. The rubber tube was used for water circulation within the double prism casing. The tube's open end should be attached to the connection just above the other one. The lower connection was used for introducing water into the system, the farther one for discharging it. The latter connection is linked with an opening to which was introduced a thermometer (see accessory) in order to calibrate the water temperature.
A pivoting arm above the double prism is equipped with a telescope tube. The refractive index of the substance introduced in the double prism encasing is measured off the graduated scale, read with the loupe. The loupe is actually fixed to an alidade that rotates the double prism on a horizontal axis. The telescope has a fine adjustment focus knob.
Illumination is provided by daylight, reflected on the pivoting mirror fixed on the base.