408 



SCIENCE. 



[N. S. Vol. IV. No. 90. 



cold periods in the whole history of the 

 globe. He sketches the supposed evidences of 

 pre-Pleistocene glaciation, and concludes that 

 only in the late Carboniferous or early Permian 

 period does the testimony for the prevalence of 

 a low temperature over a large part of the globe 

 seem at present satisfactory. He concludes that 

 a glacial epoch is a rare episode in the history 

 of the earth. In the discussion of general 

 principles of interpretation the treatment is 

 rather academic, as must needs be when under- 

 taken by a specialist in petrology. The interpre- 

 tation of glacial phenomena equals, if it does 

 not transcend, in difiiculty, that of most other 

 classes of geological phenomena, and the true 

 principles of interpretation are not likely to be 

 determined except by long and critical trial in 

 the field. 



The work is very well written but very poorly 



illustrated. 



T. C, Chamberlin. 



University of Chicago. 



loiva Geological Survey, Volume V. , Annual Re- 

 port for 1895. Samuel Calvin, State Geolo- 

 gist ; H. P. Bain, Assistant State Geologist, 

 pp. 452, 7 maps, pis. 14, 72 figs. Des Moines. 

 1896. 



The fifth volume of the publications of the 

 Iowa Geological Survey presents the same ex- 

 cellent typographical appearance which char- 

 acterizes the former volumes. These publica- 

 tions, which have appeared in rapid succession, 

 indicate continued great activity on part of 

 those engaged in the work. The title annual 

 report is rather misleading, for the subject- 

 matter contains nothing that is of temporary 

 character except the administrative part which 

 consists of a few pages only. As in the pre- 

 vious volumes of this survey there is carried out 

 the highly commendable policy established at 

 the beginning, of eliminating all matter from 

 the reports that is of a preliminary nature, and 

 of publishing only material that has been care- 

 fully digested and classified. In this way the 

 total amount of matter published is not nearly 

 so great as it otherwise would be. With great 

 advantage all work of preliminary character 

 which so often goes to make up the large bulk 

 of geological publications is omitted. Thus, 



only the work in its ultimate form is made 

 public. The set of volumes becomes the ' final ' 

 series, and only a single class of publications is 

 issued. 



The volume is devoted to areal geology, and 

 six counties are carefully and fully described. 

 One of these, Jones county, is by Prof. S. 

 Calvin, State Geologist. Three, by Prof. H. F. 

 Bain, Assistant State Geologist, are on "Washing- 

 ton, Woodbury and Appanoose counties. One, 

 by Dr. S. W. Beyer, is on Boone county ; and 

 another on Warren county is by Prof. J. L. 

 Tilton. 



In all the reports the economic aspects of the 

 mineral resources are placed prominently in the 

 foreground. Yet the purely geological phases 

 of the various questions are given full consider- 

 ation, and in a thoroughly scientific manner. 

 , Charles E. Keybs. 



NEW BOOKS. 



What is Electricity f John Trowbridge. New 

 York, D. Appleton & Co. 1896. Pp. vi+ 

 315. 



Physics for University Students. Part I., Me- 

 chanics, Sound and Light. Part II., Heat, 

 Electricity and Magnetism. Henry S. Car- 

 hart. Boston, Allyn & Bacon. 1895, 1896. 

 Pp. iv+344and446. 



Electrical Measurements. Henry S. Carhart 

 and George W. Patterson, Jr. Boston, 

 Allyn & Bacon. 1895. Pp. v+344. 



The History of Mankind. Friedrich Eatzel. 

 Translated from the second German Edition 

 by A. J. Butler, with introduction by E. B. Ty- 

 lor. Vol. I. London and New York, Mac- 

 millan & Co., Limited. 1896. Pp. xxiv+ 

 486. $4.00. 



Navigation and Nautical Astronomy. F. C. Steb- 

 BiNG. London & New York, Macmillan & 

 Co., Ltd. 1896. Pp. vii+328. $2.75. 



Astronomical, Magnetic and Meteorological Obser- 

 vations made during the year 1890 at the U. S. 

 Naval Observatory. Capt. Frederick V. Mc- 

 Nair. Washington, Government Printing 

 Office. 1895. Pp. Ixiii-f 420. 



Societa degli Alpiniste Tridentini XIX. Annuario 



1895. Eovereto, Tipografia Eoveretana. 



1896. Pp. 568. 



