Excerpt from Memoirs of the Museum of Comparative Zooelogy, at Harvard College, 1880, Vol. 6 This part of the work was, therefore, that which first received our attention. The tables in question were computed and published under the title of Contributions to Barometric Hypsometry, with Tables for Use in California. Then came the laborious operation of recalculating and arranging the barometrical observations at the various sta tions in the gravel region, the corrections indicated by the tables being applied to them. The method of applying the corrections in question, and the reasons for their use, have been fully explained in the Barometric Hypsometry, which was issued in 1874. A supplement, forming the fifth chapter of that work, was published in 1878, in which the practical value of our tables is demonstrated, by a bringing together for comparison and discussion of the results obtained by working over the many hundred observations which had been taken in the gravel region. In this division of the work it is shown that the use of the tables in question has reduced the error of the results, on the average, by fifty per cent; and I may here add, after having made a careful examination of the whole subject, that there is no method of observation by which barometric results can be freed from the class of errors which these tables are intended to remove, neither is there any kind 'of corrections which can be substituted for those furnished by our work. All these laborious computations and investigations of the barometrical data were made by Professor Pettee, or by assistants employed under his direction. It must be noticed, however, that a portion of the altitudes given in the body of this work have not had the tabular correction applied to them. Consequently they differ slightly, in numerous instances, from those published in tabular form in Appendix C, which presents in one body the result-s of all the later and more trustworthy determinations made in the gravel region proper. 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.