Gilbert, G. K. Continental Problems. Rochester, N. Y.: Geological Society of America. Pp. 12.
Glazebrook, R. T., and Shaw, W. N. Practical Physics. New York: Longmans, Green & Co. Pp. 633. $2.50.
Hague, Arnold. Geology of the Eureka District, Nevada. Pp. 419. With Plates and an Atlas.
Henderson, C. Hanford. The Cretaceous Fold of the Alps, between the Linth and the Sihl. Pp. 22. With Chart.
Hogg, Prof. Alex., Fort Worth, Texas. The Railroad as an Element in Education. Pp. 70.
Hudson, W. H. Idle Days in Patagonia. New York: D. Appleton & Co. Pp. 256. 84.
James, Joseph F. Paleontology of the Cincinnati Group. Part IV. Pp. 16.
Jenkins, Oliver P. Primary Lessons in Human Physiology. Pp. 211. Advanced do. Pp. 318. Indianapolis, Ind.: Indiana School Book Co.
Jones, Prof. George William. Logarithmic Tables. Macmillan & Co., and the Author, Ithaca, New York. Pp. 160.
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McDonald, Marshall. Report of the Commissioner of Fish and Fisheries for 1888. Washington: Government Printing Office. Pp. 902.
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Martin, Lillie J. Laboratory Exercises in Physics. Pp. 36.—Outline of Laboratory Work in Chemistry in San Francisco Girls' High School. Pp. 16.
New York State Reformatory at Elmira. Seventeenth Year Book.
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Owen, D. A., Franklin. Ind. Observations on Heloderma Suspectum. Pp. 3.
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Pilling, James Constantine. Bibliography of theLanguages. Washington: Bureau of Ethnology. Pp. 125.
Pohlman, Julius, M. D. Duration of Life of the Nervous American. Pp. 8.
Pope, Albert A. Memorial to Congress on the Subject of a Road Department. Pp. 96.
Raymon, George Lansing. Genesis of Artform. New York: G. P. Putnam's Sons. Pp. 311. $2.25.
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Shufeldt, R. W. On the Classification of the Longipennes. Pp. 5.
Smith, Roderick H., New York. The Silver Question settled. Pp. 31.
Stebbins, Genevieve. Dynamic Breathing and Harmonic Gymnastics. New York: Edgar S. Werner. Pp. 155. $1.50.
Stephen, Leslie. An Agnostic's Apology, and other Essays. New York: G. P. Putnam's Sons. Pp. 380.
Tenney, D. K., Chicago. Never-ending Life assured by Science. Pp. 15.
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United States National Museum. Report for 1890. Smithsonian Institution. Pp. 811.
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Wilson, Woodrow. Division and Reunion, 1829-1889. (Epochs of American History.) Longmans, Green & Co. Pp. 326. $1.25.
Wright, G. Frederick. Unity of the Glacial Epoch. Pp. 24.—Estra-Morainic Drift in the Susquehanna, Lehigh, and Delaware Valleys. Pp. 25.—Replies to Criticisms. Pp. 8.
Yale Review, February, 1893. Quarterly. Boston: Ginn & Co. Pp. 454. 75 cents; $3 a year.
Zola, Émile. Modern Marriage. New York: Benjamin H. Tucker. Pp. 64. 15 cents.
Number of Glacial Periods.—An article by Prof. George F. Wright, in the American Journal of Science, is devoted chiefly to showing that certain points of evidence relied upon by those who believe that the "Glacial epoch" consisted of two periods of glaciation of similar extent separated by a long interglacial epoch, are insufficient to afford a basis for such a conclusion. Furthermore, the author adds to this: "As bearing against the duality of the Glacial period, it may be urged with great force that it is improbable that two periods should so nearly duplicate one another as these two are supposed to have done. To those who maintain the sufficiency of Croll's astronomical cause, however, this is rather an argument in favor. But, on the other hand, that cause would also demand a long succession of periods during all the geological ages, and of these we lack sufficient proof; while it would throw the two periods which Prof. Chamberlin recognizes back much farther than the facts will admit. It must be said, however, that it is not wholly out of analogy with known earth movements to suppose that