Magnetical And Meteorological Observations Made At Washington Astronomical Observations Made At The Naval Observatory Washington Under Orders Of The Honourable Secretary Of The Navy Dated August 13 1838 By Lieutenant J M Gilliss

Excerpt from Magnetic and Meteorological Observations Made at Washington Under Orders of the Hon. Secretary of the Navy: Dated August 13, 1838 The magnetical observatory was built entirely of wood, secured with pins of the same material, or copper nails; every precaution being taken to exclude metals likely to disturb the magnets. Within it, and at a distance of six feet from each other, were two sandstone piers, for the support of the instruments; the plane in which they were placed being perpendicular to the magnetic me ridian, and the eastern pier in the meridian of the transit instrument in the astronomical observa tory. They were entirely detached from the floor. Above it, their elevation was forty two inches; and the shafts being eight feet long, their bases were nearly four feet below the surface of the ground, and consequently beyond the action of frost. Meridian openings in the roof, twenty inches wide, corresponded with each pier, and permitted a view of the heavens to within Wu degrees of the horizon; the observatory to the north and Capitol to the south, interrupting it to that elevation. To preserve the room from extreme as well as sudden changes of temperature, and reduce the range of the internal thermometer as much as the nature of its construction would per mit, the building was entirely covered with an awning of painted canvass, distant from it three feet, and which screened it from the direct action of the sun or weather, except early in the morning and late in the afiemoon. 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.