Page:Popular Science Monthly Volume 46.djvu/433

Rh large number of students of astronomy whose instrumental equipment is not adequate to the satisfactory observation of a considerable proportion of the objects described in Smyth's and Webb's catalogues of celestial objects suited to observations with common telescopes. Those who have equatorially mounted telescopes of more than three or four inches aperture may find these works all they need; but those who have only altazimuths of smaller apertures will be liable to embarrassment from the difficulty of locating the objects described in these works, and by the presence in their lists of many that can not be seen at all with those instruments. For the purposes of this work objects are selected which are within the powers of such instruments, and the attempt has been made to describe their location so that they may be easily found without the aid of a map or lantern light. Price, $1.25.

Hermon C. Bumpus has had in mind, in the preparation of his Laboratory Course in Invertebrate Zoölogy (Henry Holt & Co., New York, $1), the requirements of a class of students who are pursuing a course of laboratory work on the subject. An effort has been made to direct the work without actually telling the student all that is to be learned from the specimen. An instructor is supposed to be present to assist with the hard points, and to demonstrate what can not well be elucidated by written descriptions. Not always the most typical animals are selected, but forms easily procured and preserved have been looked for. The orders of Protozoa, Cœlenterata, Echinodermata, Vermes, Mollusca, Crustacea, Limulus, Arachnoidea, and Antennata are represented by from two to seven genera each.

The work of Dr. Hermann Adler on Alternating Generations, based on A Biological Study of Oak Galls and Gall Flies, is published by Macmillan & Co., translated with the permission of the author, and edited by Charles R. Stratton. The translator became acquainted with the work while studying galls as a branch of comparative pathology, and was struck with its originality and the light it threw upon certain great biological problems. Dr. Adler began his observations of gall flies in 1875, and in the course of his investigation was able to unfold their life history, and to prove that, while many species are linked together in alternate agamous and sexual generations, others are wholly agamous. Since the existence of alternating generations was discovered by Chamisso, fresh instances of like phenomena have accumulated in which the life-cycle of the species may be represented by two or more generations, differing in form and organization, existing under different conditions, and reproducing themselves in different ways. While the galls and their generations are described by Dr. Adler, the translator suggests in the introduction a number of inquiries respecting the philosophy of the phenomenon, and especially concerning the nature and operation of the excitation by which the peculiar fruitlike forms are produced upon the trees as the result of the gall fly's work. Colored illustrations are given of forty-two species of oak galls. Price, $3.25.

Canadian Independence, Annexation, and British Imperial Federation (Putnams, 75 cents) is the amplification of an essay first written for Canadian readers by a Canadian, James Douglas, long resident in the United States. The imminence of political change in Canada, independence as an essential factor of imperial federation, annexation as an alternative to independence, Canada's slow progress, the probable effect of annexation on Canadian industries and wages, annexation from the point of view of comparative politics, and annexation from American and Canadian points of view are considered. The author believes that all the advantages expected from annexation can be obtained by reasonable trade arrangements.

An elementary text-book, with the title Geometry for Grammar Schools, has been prepared by E. Hunt, LL. D. (Heath). Large use of drawing is made in it, and paper cutting and folding are somewhat employed. The problems are an extension of those on mensuration usually found in text-books of arithmetic. Two copies of a protractor are printed in such a manner that the pupils may cut them out and use them in drawing.

Prof. Dolbear's book, Matter, Ether, and Motion, the first edition of which was noticed in this magazine in 1892, has reached a second edition (Lee & Shepard, $2). Three chapters have been added, dealing respectively with Properties of Matter as Modes of Motion, Implications of Physical Phenomena,