Method and refractometer for measuring the refractive index of a liquid and application to the measurement of the alcoholic strength of a must

摘要

The refractometer consists of a tank 3 in which a sample 1 of the liquid is placed, a prism 1 with one of its faces 2 forming a wall of the tank, a lamp 5 illuminating a side face 8 of the prism and a fixed telescope 10. The telescope has two photoelectric cells 12a, 12b in its focal plane, mounted on a carriage 13 which is moved by a micrometer screw 14 incorporating a digital detector of angular displacement. Pulse counting is stopped when the signals emitted by the two cells are equal. Application to the measurement of the alcoholic strength of a natural must. IMAGE