Optical Rotatory Power of Turbid Solutions in an Electric Field

WE have been investigating the effect described by Prof. Kunz and R. G. LaBaw, first in conjunction with McLean, who, however, had to leave it to take up other work. Although the solutions were apparently quite clear and free from obvious particles, we were led to suspect in some cases that the result might be due to very minute crystals in suspension in the liquid ; we have also heard from Prof. Kunz that he has come to the same conclusion. Very careful filtration through selected filter papers removes the optical activity. The conclusion is, then, that the effect is due to dichroism induced in the particles by the electric field, a phenomenon not entirely new, although its accurate quantitative investigation is beset by numerous difficulties.