to the neuroses of the heart, and the portion on valvular affections also deserves special mention. The next two articles, Diseases of the Blood-vessels, by Dr. A. Ernest Sansom, of London, and Diseases of the Lymphatic Vessels, by Dr. Bertrand Dawson, also of London, seem to be complete, and to bring the subject up to date. The closing article is one of especial interest, by Dr. George Murray on diseases of the thyroid gland, including myxoedema, cretinism, exophthalmic goitre, and goitre, as well as inflammation and neoplasms.
A Revision of the Deltoid Moths, by John B. Smith, forms Bulletin No. 48 of a series of Smithsonian publications which are intended to illustrate the collection constituting the National Museum. Under the general term deltoids there are usually grouped in lists, catalogues, and collections the moths of a series of species and genera which have a somewhat distinctive appearance and habitus, but for which we have as yet no exclusive characters. The home of the group is in that region extending from Maine through Canada, west to the Great Lakes, southward along the Mississippi, and eastward through Ohio along the southern boundary of Pennsylvania to the Atlantic coast. All the species fly at night and are readily attracted to light and sugar. The book is well made, but will only be of interest to the specialist. It is illustrated with fourteen plates.
The third edition of Mr. Alfred Daniel's Text-hook of the Principles of Physics (Macmillan & Co., $4) has recently come to us. It maintains the characteristics of the previous editions, of clear statement and simple arrangement, and improves upon them in the correction of some minor errors which recent researches have brought to light, and in the adoption of a uniform notation, which will prove a great help to the student. Every equation is considered from the point of view of its dimensions, and this has necessitated the modification of some of the original text accordingly. The book is intended either as a preparation for the more valuable laboratory work of experimental physics or for those who have no access to a laboratory, and who must derive their physics entirely from book reading. Any one having a fair knowledge of mathematics ought to have no difficulty in following the text, which is illustrated wherever clearness is gained.
A valuable little textbook on Alternating Currents, by E. J. Houston and A. E. Kennelly, is the latest volume of the Electro-Technical Series to reach us. This subject of alternating currents is probably the most important and most difficult portion of modern electrical science. It is the department in which most of the advanced experimenters are working, and from which new and valuable results may at any time be expected. A very clear and simple explanation of the two forms of currents is first given, their differences explained and accounted for, and the means by which one may be transformed into the other described. The more important commercial applications of the alternating current in electric lamps and motors are then described in detail. Chapter XVII, which closes the book, discusses multiphase motors. (W. J. Johnston Co., N. Y.)
The Fourteenth Annual Report of the United States Geological Survey, for the years 1892-1893, consists of two volumes, the first of which contains the general reports of the director and heads of divisions. The second consists of a series of monographs on geology and related subjects. The first paper, by W J McGee, discusses the potable waters of the eastern United States. He first points out the large part which water takes in our dietaries, and the dangers which arise through its contamination; and then gives a general history of the methods which have been employed for storing and purifying it. In the next article A. C. Peale deals with the natural mineral waters of the United States. The different varieties are named and classified, and the paper is closed by an extended index of the mineral springs, arranged according to States. The Results of Stream Measurements is the title of the third paper, by F. H. Newell. The methods and special instruments by which the measurements are made are first described, and then the data resulting from their employment on various rivers are given. Besides these there are articles on the Laccolitic mountain groups of Colorado, Utah, and Arizona; The Gold-Silver Veins of Ophir, California; Geology of the Catoctin Belt; Tertiary Revolution in the Topography of
