This book is a pioneering work of scientific investigation into the chemical composition of air and rain, and its implications for understanding the earth's climate. Smith's groundbreaking research, conducted in the mid-nineteenth century, laid the foundation for modern studies of atmospheric chemistry and the effects of pollution on the environment. With its clear and accessible prose, this book is essential reading for anyone interested in the history of science and the origins of environmentalism. 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.