Smithsonian Geographical Tables (Classic Reprint)

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Excerpt from Smithsonian Geographical TablesThe second difficulty arose from the present uncertainty in the relation of the British and metric units of length, or rather from the absence of any generally adopted ratio of the British yard to the metre. The dimensions of the earth adopted for the tables are those of General Clarke, published in 1866, and now most commonly used in geodesy. These dimensions are expressed in English feet, and in order to convert them into metres it is necessary to adopt a ratio of the foot to the metre. The ratio used by General Clarke, and hitherto gener ally used, is now known to be erroneous by about one one hundred thousandth part. The ratio used in this volume is that adopted provisionally by the Office of Standard Weights and Measures of the United States and legalized by Act of Congress in 1866. But inasmuch as a precise determination of this ratio is now in progress under the auspices of the International Bureau of Weights and Measures, and inasmuch as the value for the ratio found by this Bureau will doubtless be generally adopted, it has been thought best in the present edition to restrict quantities expressed in metric measures to limits which will require no change from the uncertainty in question. In conformity with this decision the dimensions of the earth are given in feet only, and, with a few unimportant exceptions, to which attention is called in the proper places, tables giving quan~ tities in metres are limited to such a number of figures as are definitely known.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis 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.