Pulfrich refractometer

Pulfrich refractometer

[′pu̇l·frik ‚rē‚frak′täm·əd·ər]
(optics)
A critical angle refractometer in which the material to be tested rests on a prism of material of known higher index of refraction and angle, and the angle of refraction of light which is directed at the interface between the two materials at grazing incidence is observed.