LITERARY NOTICES. 



State so far as determined during the two 

 years' existence of the survey. In the course 

 of the second year the co-operation of the 

 United States Geological Survey and of the 

 United States Coast and Geodetic Survey 

 were secured in topographical work, much 

 to the advantage of all branches of the work 

 of the State Survey. Several geologists 

 worked during the year at mapping the iron 

 ores of the east Texas district, and the 

 associated clays and lignites were also stud- 

 ied. Prof. Robert T. Hill studied the eco- 

 nomic geology of the Cretaceous area, but 

 resigned from the survey without making 

 his report. Prof. W. F. Cummins was en- 

 gaged in a detailed study of the coal meas- 

 ures of the central coal field ; the Guadalupe 

 Mountains were explored by Mr, Tarr ; and 

 further work on the mineral resources of cen- 

 tral Texas was done by Dr. T. B. Comstock, 

 who discovered tin in this region and obtained 

 much information concerning the deposits of 

 other metals, and of granite and salt. In the 

 trans-Pecos region. Prof. W. H. Streeruwitz, 

 after completing the topographic mapping 

 of an important area, spent the rest of the 

 season in examining the mineral veins of 

 the region. For lack of books and type 

 specimens most of the paleontological work 

 on the Texas rocks has been done outside 

 the State. An offer by the State Geologist 

 to furnish collections of the rocks and miner- 

 als of Texas to the high schools of the State 

 brought more applications than could be 

 filled ; forty-one sets, more or less complete, 

 were furnished. The details of the year's 

 work are given in the papers accompanying 

 the report of Prof. Dumble, the text being 

 illustrated with maps of the several localities, 

 drawings of sections, and photographic views. 



An Introdttction to the Mathematical 

 Theory of Electricity and Magnet- 

 ism. Bv W. T. a. Emtage. New York : 

 Macmillan&Co, Pp.228. Price, $1.90. 



This work, which appears in the Claren- 

 don Press Series, is adapted to students far 

 enough advanced to possess a knowledge of 

 differential and integral calculus. It is 

 complete in itself, and may be read without 

 previous knowledge of the subject. Purely 

 experimental parts of the subject requiring 

 no special mathematical treatment have been 

 entirely omitted. 



Plane and Solid Geometry. By Seth T. 

 Stewart. New York : American Book 

 Company, Pp. 406. Price, $1.12. 



Prominent features of this text-book are 

 its strict adherence to the principle of asso- 

 ciation and its graded exercises. Each book 

 treats of one subject, and each section treats 

 of one subdivision of the subject, so that all 

 relating to the subject or its subdivisions 

 being placed together, the several parts will 

 support one another in memory by the law 

 of association. The same method of arrange- 

 ment — the resultant form of the book being 

 one that is rendered possible only by the 

 grouping of propositions — favors the regular 

 gradation of exercises. At the end of each 

 section miscellaneous exercises, assorted and 

 graded, are presented in an order intended 

 to promote, by their successive solution, a 

 constant growth in the power of analytic and 

 synthetic thought. A synopsis of each book 

 precedes the book itself, as an encourage- 

 ment to students to work independently of 

 the demonstrations given in the text. Thus, 

 before giving the definitions of points, lines, 

 and angles, the pupil is set to construct them 

 if we may use the word, after which the 

 definition follows, of necessity; and so on, 

 through the book. The inductive method is 

 in this way employed in the treatment of 

 each part of the work ; but, while the ap- 

 proaches to the subject are thereby rendered 

 more agreeable, the author has been con- 

 servative in retaining, as far as possible, 

 the usual phraseology of propositions and a 

 wholesome rigor in demonstration. Through- 

 out the volume the diagrams and demonstra- 

 tions are in full view of each other. 



No. 3, Vol. rV, of Tlie Journal of Mor- 

 phology, contains seven papers. The first 

 embodies some Studies on Cephalopods, in 

 regard to Cleavage of the Ovum, by S. 

 Watasc. It is illustrated with four plates 

 and nineteen figures in the text. J. Play- 

 fair McJfu7-rich has a second installment 

 of his Contributions on the Morphology of 

 the Actinozoa in this number, dealing with 

 the Development of the Hexactiniae, It is 

 accompanied by a plate. There are short 

 papers by G. Baur on Intercalation of Ver- 

 tebrec, and by W. M. Wheeler on Neuro- 

 blasts in the Arthropod Embryo. G. Baur 

 also contributes a paper on The Pelvis of 



