tions, having had entire charge of the mechanical tests. In the chapter on the characteristics of wood a list of over a hundred timber-producing trees of the United States is given, with a brief description of each and a figure of its leaf and fruit. The part of the volume upon which the author expects the student to put his serious work relates to the methods of applying tests of materials and to the machines employed in testing. This is followed by a group of chapters relating to the mechanical properties of the materials of construction as revealed by actual tests, in which the author expects that selections will be made for students according to the course they are taking. Among the special subjects here treated are the strength of iron and steel wire and wire rope, and the magnetic testing of iron and steel. The volume is illustrated with six hundred and thirty-five figures and diagrams and eleven plates. The author has avoided the use of tables, preferring to arrange in diagrams the data often appearing in tabular form. There are appendices relating to the micrographic analysis of iron and steel, to attempts to secure uniform tests of materials, and to standard specifications for structural steel.
Our material for the study of infant psychology has received a carefully prepared addition in The Mental Development of a Child, by Kathleen Carter Moore, issued as a monograph supplement to the Psychological Review (Macmillans, paper, $1). This is a record by a mother embracing the manifestations of activity and of change in her own child, and the conditions under which each action or change was manifested. This material is supplemented by summaries reviewing the mental condition of the child at given periods. The first of these reviews overs all lines of activity; later, when there was more to record, each set of activities is summarized separately. The observations are grouped under the four chief heads Movements, Sensations, Ideas, and Language, and many of them, especially those relating to language, are tabulated besides being described.
The sixth volume of the series in Philolology, Literature, and Archæology of the publications of the University of Pennsylvania is devoted to Researches upon the Antiquity of Man, by Henry C. Mercer (Ginn, $2). The contents comprise descriptions of excavations made and articles found in several localities, and are introduced by a discussion of the chipped stone implements which are the most numerously preserved examples of the handiwork of savage man. The first finds herein described are those made at an ancient argillite quarry and blade workshop on the Delaware River. Here were found one hundred and seventy-four hammer stones, large numbers of "turtle backs" and chips, and a few miscellaneous objects. An account of the exploration of an Indian ossuary on the Choptank River, in Maryland, is given by Mr. Mercer, with a description by the late Prof. Cope of the human bones discovered there, and an examination by R. H. Harte, M. D., of traces of disease in the bones. There are also accounts of explorations of aboriginal shell heaps on York River, Maine, where traces of cannibalism were found; of a rock shelter in the Delaware Valley and of Durham Cave, in Bucks County, Pennsylvania. The text is illustrated with fifty-one figures and diagrams.
The Philosophical Society of Washington has issued a substantial volume as the twelfth in its series of Bulletins, containing the publications of the society from 1892 to 1894. The address of Prof. T. C. Mendenhall, as retiring president, on The Uncertainty of Conclusions, and that of G. K. Gilbert, also as retiring president, on The Moon's Face, are included in the contents, and among the more extended papers are The Origin of Igneous Rocks, by Joseph Paxson Iddings; Summer Hot Winds on the Great Plains, by Isaac Monroe Cline: and Mean Density of the Earth, by Erasmus Darwin Preston. Several of the papers are accompanied by views or diagrams. There are obituary notices of eleven members, those of Garrick Mallery and James Clarke Welling being accompanied by portraits.
An elementary text-book on Electricity and Magnetism has been prepared by Prof. Charles A. Perkins (Holt, $1.10), which, while it acknowledges the impossibility of such a work being up to date, still aims to implant initial conceptions that are in ac-
