This book is a collection of the Proceedings of the Royal Society of London from Volumes 15 through 19. The Proceedings contain scientific papers and discussions from some of the most prominent scientists of the 19th century, including Charles Darwin, Michael Faraday, and William Thomson (Lord Kelvin). This edition includes an index of authors and subjects for easy reference. 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.