This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

Books are still among the most important cultural achievements of humanity. Their invention was as important as the Internet: for the first time, a mass transfer of information became possible. Education, science, research, but also entertainment was based on a new revolutionary basis. Books are changing society until today. The technical possibilities of mass printing led to a radical increase in titles in the 18th and 19th centuries. Nevertheless, the conditions were still very different than today: Who wrote a book at that time, often wrote a life's work. This is reflected in the high quality of old books. Unfortunately, books age. Paper is not made for eternity. Therefore, we have made it our mission to preserve the book of knowledge of humanity and to make old books available in high quality at low prices

This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book.