photopolarimeter

Century Dictionary and Cyclopedia

1. n. A form of polarimeter devised (1885) by Cornu. It has a doubly refracting prism mounted at one end of a tube, which at the other has a diaphragm of such size that the borders of the two images, polarized at right angles, just coincide with each other. A nicol prism suitably mounted is made to revolve until these images have the same intensity, when the angular position of its plane of vibration gives a ready means of determining the degree of polarization in the light under examination.

Wiktionary

1. n. A combination of a polarimeter and a photometer