Abbe Refractometer

Listing ID #4150607

Heavy casted round base with aluminium body and all other parts of plated brass. Fixed body leaned at 600 angle, Abbe double prisms with the thermostat, compensator, telescope mirror, limb, graduated sector, reading magnifier and radial arm which carries vernier. Abbe’s double prisms leaves a narrow space between the adjoining faces of the prisms. Compensator consists of the amici prisms which serve for rendering the line of achromatic separation.

Adjust the eye pieces of both telescopes and reading magnifier, so that well defined images of cross lines and scales is obtained. Open the Abbe’s double prism and put two or three drops of liquid upon the adjoining face of the prism for measuring. When the prisms are closed the liquid spreads over the whole surface of the prisms forming a thin layer. Adjust the mirror to get proper incident light, and also the compensator and radial arm, so that the boundary line of bright and dark is clearly seen in the visual field of telescope. Turn radial arm by means of fine adjustment to bring the line precisely on the cross line and read of scale on the sector. For the dark color substance to be examined as molasses, fructose or jam, the light from the mirror is not sufficient for observation, take off the cover of the circular opening. Then the light proceeds so as to be reflected on the boundary surface and the prism for convenient observation.

Abbe double prisms are heated by a double jacket metal casing in which warm water under 70°C circulates. Temperature of water can be adjusted and read by the thermometer fitted at the double prism. To check the instruments for its accuracy with the aid of the standard plate and liquid that accompanies. Apply a small drop of standard oil on the standard plate and place it with a gentle pressure upon the face of the polished refractometer prism. Critical line should then be achromatized by means of compensator. Repeated readings should be taken, and compare the result of readings with the value of index mentioned on the standard plate. Complete with standard glass test plate, 4 ml. Monobrom Naphthalene (contact liquid), thermometer in a metal jacket, zero aluminium knob, brush, dust cover in a wooden cabinet.