Barometric Hypsometry With Tables For Use In California

Excerpt from Contributions to Barometric Hypsometry: With Tables for Use in California Having been, for more than twenty-five years, almost constantly employed in geological surveys of our Western States, I have had occasion to use the barometer quite extensively as a hypsometrical instrument. As early as 1847, being engaged in determining the height of points along the south shore of Lake Superior, I became convinced that there were sources of error in our barometrical work which had not been sufficiently taken into account; and by repeated measurements of a number of elevations at different seasons and hours, I arrived at the conclusion that our results were always lower in cold weather, or at morning and evening, than they were in warmer weather or towards noon. I or some years after this my field of labor was among the prairies of the Mississippi Valley, where there was little occasion for hypsometrical work, and the subject of the uncertainties and perplexities of barometrical determinations of heights was for a time dismissed from my thoughts. Later, however, on taking charge of the Geological Survey of California, where the barometer became again an instrument of the greatest importance, and indeed an indispensable companion in our field-work, the same difficulties which had been met with on Lake Superior ban again to be noticed, and to call for investigation. 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.