Excerpt from Positive and Negative Photoelectrical Properties of Molybdenite and Other Substances The object of the present paper is to place on record some recent observations on photosensitivity' and in particular the photo negative phenomena observed in a certain sample of molybdenite. The importance of having a record of such unusual phenomena will be apparent from the fact that heretofore the mention of such data has been merely incidental. These isolated bits of information have been assembled in the present paper in order to Show their relation to the newly observed data. 't he whole compilation is but little more than a starting point in a new line of research that may yield information which Will explain the phenomenon of photoelectric sensitivity. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.