Excerpt from Observations on Days of Unusual Magnetic Disturbance, Vol. 1: Made at the British Colonial Magnetic Observatories, Under the Departments of the Ordnance and Admiralty; 1840-1841 On a review of the accord which shows itself in the diurnal march of each element in the different months, we may feel justified in regarding the mean monthly positions at the several observation hours as approximate normal positions; and we may view the difference between the actual position at any hour during the month, and the normal position at the same hour, as the effect of disturbing causes. 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.