Transcriber’s Note When italics were used in the original book, the corresponding text has been surrounded by _underscores_. Some corrections have been made to the printed text. These are listed in a second transcriber’s note at the end of the text. PHYSICAL GEOGRAPHY. BY MARY SOMERVILLE, AUTHOR OF THE “CONNECTION OF THE PHYSICAL SCIENCES,” “MECHANISM OF THE HEAVENS,” ETC., ETC. SECOND AMERICAN, FROM THE NEW AND REVISED LONDON EDITION. WITH ADDITIONS AND A GLOSSARY PREPARED FOR THIS EDITION. ---------------------------- PHILADELPHIA: LEA & BLANCHARD. 1850. ENTERED, according to Act of Congress, in the year 1849, by LEA & BLANCHARD, in the Clerk’s Office, of the District Court of the Eastern District of Pennsylvania. TO SIR JOHN F. W. HERSCHEL, BART., K.H., &c., &c. DEAR SIR JOHN, I avail myself with pleasure of your permission to dedicate my book to you, as it gives me an opportunity of expressing my admiration of your talents, and my sincere estimation of your friendship. I remain, with great regard, Yours truly, MARY SOMERVILLE. _London, 29th February, 1848._ ADVERTISEMENT. THE improvements and additions embodied in the new London edition are fully enumerated in the Author’s Preface. The American publishers have supplied what was much needed, a complete Glossary of Scientific and Technical Terms; which, with some few additions scattered through the pages, and enclosed in brackets [ ], were prepared by Dr. Ruschenberger. These additions, while they have improved the work, have added materially to the number and size of the pages. The publishers, consequently, trust that it will be found more effectually suited to the wants of the private reader as well as to those of the higher classes in schools. _Philadelphia, December, 1849._ PREFACE TO THE NEW EDITION. SINCE the publication of the first edition of this work, the Author has been able to correct many inaccuracies that had crept into it, and to collect much new matter from works since published, which is embodied in the present edition, and has considerably added to its size. The recently-published Second Volume of Baron Humboldt’s invaluable “Cosmos,”[1] with Colonel Sabine’s learned notes, and sundry papers that have appeared in the scientific periodicals of Europe, America, and India, bearing on questions of Physical Geography, have yielded profitable information.