particularly emphasizes the rapid advance made in all educational matters during the last decade. Since 1880, "each year has chronicled a steady advance, and the aggregate results will bear favorable comparison with the educational statistics of any other State. The superintendent has been able to report a gratifying progress in nearly every particular: in the growth of the schools in public favor; in the increased number of schools and school children; in improved buildings and enlarged funds; in a more intelligent and better instructed body of teachers; in a lengthened school year; and in a ratio of attendance which, if correctly reported, probably can not be surpassed in any of the older States." Messrs. Allen and Spencer's "Higher Education in Wisconsin" is the first of a series of monographs on the group of Northwestern States in the angle between the Ohio and the Mississippi Rivers. It gives only a general outline of the career of each of the colleges, mostly compiled from the sketches in their alumni records and similar publications. The larger share of space is given to the State University. The five private colleges are described as to the leading features and character of each and the scope and tendency of their work; and brief notices of three others are given. The execution of all these histories might be improved upon. Mr. Meriwether's on South Carolina shows the most painstaking, but it is considerably short of what such a work ought to be.
Commercial Organic Analysis. By Alfred H. Allen. Second edition, revised and enlarged. Vol. III, Part I. Acid Derivatives of Phenols, Aromatic Acids, Tannins, Dyes, and Coloring Matters. Philadelphia: P. Blakiston, Son & Co. Pp. 431. Price, $4.50.
Analysts will welcome the third installment of this comprehensive and carefully prepared work, which details the properties, methods of proximate analytical examination, and assaying of the various organic chemical substances employed in the arts, manufactures, and medicine. The material has so increased during revision that it will occupy at least double the space of the original two-volume edition. The part now issued consists of a chapter on aromatic acids, with an appendix descriptive of the tannins, and a chapter on dyes and coloring matters. The material relating to the latter subject is almost all new, coloring matters having been represented in the first edition only by sections on picric acid and basic anilin derivatives. In the present edition these substances are treated under the following ten divisions; nitro and nitroso coloring matters, aurin and its allies, phthaleins, azo coloring matters, rosanilin and its allies, safranines and indophenols, coloring matters from anthracene, sulphureted and unclassified coal-tar dyes, and coloring matters of natural origin. There remain to be treated in the second part of Vol. III, which will complete the work, organic bases, cyanogen compounds, albuminoids, etc.
Stellar Evolution and its Relations to Geological Time. By James Croll. New York: D. Appleton & Co. Pp. 118. Price, $1.
Mr. Croll in this book presents what he calls the "Impact Theory" of stellar evolution—a theory which, as applied to our sun, supposes that it was formed from a hot gaseous nebula, produced by the colliding of two dark stellar masses. The stars, being suns like our own, in all likelihood had a similar origin. He believes that this theory, which was proposed as a hypothesis some twenty years ago, has been strengthened by the astronomical and physical facts that have accumulated since that time. The hypothesis does not exclude the nebular theory, but rather includes it, and enlarges it by supposing what was in the world previous to the nebulæ. It assumes that previous to their formation there were stellar masses in motion; that the motion was in straight lines, and, as to each mass, without reference to the existence of any other; that two or more of these masses would casually collide; and that the collision would result in the breaking of them up, with the production of heat, and the rebounding of the fragments upon one another would end with the resolution of the whole into a nebula of inconceivably high temperature, whence the universe has been evolved, as supposed by Laplace's hypothesis. Here is an unlimited source for the energy possessed by the sun and solar system, to which the only conceivable alternative is gravitation. The latter is held to be inade-
