SCIENTIFIC LITERATURE. 419 



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 volca- 

 noes, 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 charac- 

 teristics 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 vol- 

 canic mountains and lava sheets, and more particularly as " the great vol- 

 canic 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 pic- 

 tures, 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 ob- 

 tainable 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 ordi- 

 nary 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, Sew- 

 age-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 



* Water Supply : Considered principally from a Sanitary Standpoint. By William P. Mason. 

 Illustrated. New York : John Wiley & Sons. Pp. 480. Price, $5. 



