SCIENTIFIC LITERATURE. 



56; 



tions, having had entire charge of the me- 

 chanical tests. In the chapter on the char- 

 acteristics 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 re- 

 lating to the mechanical properties of the 

 materials of construction as revealed by ac- 

 tual tests, in which the author expects that 

 selections will be made for students accord- 

 ing to the course they are taking. Among 

 the special subjects here treated are the 

 strength of iron and steel wire and wk-e 

 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 psy- 

 chology has received a carefully prepared 

 addition in The Mental Development of a 

 Child, by Kathleen Carter Moore, issued as 

 a monograph supplement to the Psychologi- 

 cal Review (Macmillans, paper, $1). This is 

 a record by a mother embracing the mani- 

 festations 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 summaiies re- 

 viewing the mental condition of the child at 

 given periods. The first of these reviews 

 covers 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 de- 

 scribed. 



The sixth volume of the series in Philol- 

 ology, Literature, and Archaeology of the 

 publications of the University of Pennsyl- 



vania is devoted to Researches upon the An- 

 tiquity of Man, by Henry C. Mercer (Ginn, 

 $2). The contents comprise descriptions of 

 excavations made and articles found in sev- 

 eral localities, and are introduced by a discus- 

 sion of the chipped stone implements which 

 are the most numerously preserved exam- 

 ples 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 ex- 

 amination by R. H. Harte, M. D., of traces 

 of disease in the bones. There are also ac- 

 counts of explorations of aboriginal shell 

 heaps on York River, Maine, where traces 

 of cannibalism were found ; of a rock shel- 

 ter 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 publrcations of the society from i892 to 

 1894. The address of Prof. T. C. Menden- 

 hall, 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 accom- 

 panied 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- 



