The books cover what was known of the "natural sciences" at the time, including what would now be called material science, physics, chemistry and technology as well as the natural history of animals.

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.

This is a reproduction of the original artefact. Generally these books are created from careful scans of the original. This allows us to preserve the book accurately and present it in the way the author intended. Since the original versions are generally quite old, there may occasionally be certain imperfections within these reproductions. We're happy to make these classics available again for future generations to enjoy!