Page:Popular Science Monthly Volume 52.djvu/435

Rh subject, much is compiled from the works of others. The scope of the book embraces the numerous still steaming and recently extinct volcanoes of Mexico and the Central American republics, some of which have had their birth since the Spanish conquest, with examples of violent eruptions which the region furnishes; the lofty volcanic mountains of California, Oregon, and Washington, with the lava beds east of them; and still active volcanic energy in Alaska. The first chapter treats of the characteristics of volcanoes, of which the world is drawn upon for types; stages in their lives, characteristics of their products, their profiles and structure, the erosion to which they have been subjected, subterranean intrusions, and the characteristics of igneous rocks. Next is described the general distribution of the active and recently extinct volcanoes of North America. The volcanoes of Central America are enumerated, their geological relations are fixed, and they are described as "young" and "older" volcanoes, in the third chapter. The fourth chapter relates to the volcanoes of Mexico. The volcanoes of the United States are described generally through typical examples of volcanic mountains and lava sheets, and more particularly as "the great volcanic mountains of Oregon and Washington," the "Cascade Mountains," "Columbia Lava," volcanoes of the Coast Range, volcanoes of the Rocky Mountain regions, and volcanoes of Alaska. The concluding chapters are devoted to deposits of volcanic dust, and theoretical considerations, among which the interior heat of the earth, the action of pressure, the agency of water, and the chemical, mechanical, and "steam" hypotheses are noticed. The last chapter gives a very interesting description of the life history of a volcano. The book is well illustrated with charts, maps, and smaller pictures, and is supplied with a satisfactory index.

The books which for a small consideration will tell us what to eat, what to read, and even what to wear, are very plentiful; but with the exception of the pamphlet literature of the "total abstainers," whose sole interest is in water per se without reference to its quality, there is little information obtainable by the general reader regarding what to drink. For this reason, if for no other, such a book as the present one ought to be kindly received. It is a treatise covering very well, in a popular way, the questions relating to the sanitation of potable waters; what water is fit to drink, the ordinary impurities, their effect on its potability, and the various methods by which the injurious contents may be removed. That the subject is an increasingly important one nobody will dispute. The growing tendency toward concentration in cities makes the water-supply question one of great difficulty, the dangers from its careless or ignorant solution being grave and far-reaching. The first chapter in the present volume gives a brief historical account of the ancient water supplies of Carthage and Rome. Drinking water and disease are next discussed. Some of the subtitles under this heading are: Paludal Poisoning, Sawdust Water, Wholesomeness of Hard Waters, Influence of Turbidity on Health, Sewage-polluted Waters, Odors and Tastes found in Waters. Chapters three and four deal with the artificial and natural purification of water. These are the most important portions of the book to the engineer and taxpayer, taking up the question of water supply in its economic and commercial