Excerpt from Notes on the Zeeman Effect: Dissertation Submitted to the Board of University Studies of the John Hopkins University for the Degree of Doctor of Philosophy Reese also states, in referring to certain lines in the Spectrum of iron, that In comparing the separation of the lines between 3900 and 4450 it was at once observed that the lines could be broken up into two classes in each of which the separation of the various lines was of the same magnitude. These two classes are identical with those for which Humphreys found that the shift due to pressure was the same. On these plates the separation is very small in all cases, owing to a weak field and no accurate measurements were taken of the separation. 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.