and technical discussions have been for the most part excluded from the body of the work and printed at the end of the volume in notes. The wider application than that to the special object of the research of which many discoveries are susceptible is illustrated in the modern very general use by farmers and fruit-growers, in all parts of the country, of pyrethrum in the field, of petroleum emulsions, and of the cyclone spraying-nozzle, all of which have had their origin in this investigation. The report gives a full account of the cotton-worm, its character, habits, and history; of the influences that affect it, its natural enemies, the preventive measures to be taken against it, and the remedies, and machinery, and devices for accomplishing its destruction; a chapter on the boll-worm; and a number of special reports in the Appendix.
Duffy's Wave-Motor as a Source of Power for Various Purposes. By Terence Duffy. San Francisco: 948 Gerry Street. Pp. 15.
Mr. Duffy has sought an invention to utilize the enormous energy of waves as a source of power, and for the movement of mechanism. He has devised a buoy, with internal arrangements and machinery by which a set of pumps shall be set in motion by the undulations to which it is subjected, to supply a reservoir of compressed air; this air to be applied to any purpose for which it may be desired. Among the applications suggested in the pamphlet are the generation of electricity; signal, relief, and light stations; propulsion of vessels; and the movement of machinery on shore. The structure of the buoy, with all its chambers and mechanism, and the application to these purposes, are set forth in the pamphlet. We see nothing in the text, however, from which we are enabled to affirm that the author has set up one of his buoys and put it to an experimental test.
The American Journal of Biology. Quarterly. Edited by H. D. Valin, M. D.Chicago: Published by the author. $1 a year.
The "Journal," according to the editor's prospectus, is devoted to the study of life and mind in its widest sense, and will consist mainly of articles written especially for its pages by persons competent to treat the subject. Each number is intended to contain sixty pages. The present number is published with only forty-four pages, but with a promise to make up the deficiency in the next number, which will consist of seventy-six pages. It contains papers on "The Laws of Life outlined," "Origin of Flowers," "Nature of Animal Colors," "Nature of Light," "Development of the Eye," and "Nature of Sight," and selections.
Mechanics of the Girder. A Treatise on Bridges and Roofs. By John Davenport Crehore, C. E. New York: John Wiley & Sons. Pp. 575. Price, $5.
In this purely technical treatise, the necessary and sufficient weight of the structure is calculated, not assumed; and the number of panels and height of girder that render the bridge-weight least for a given span, live load, and wind-pressure, are determined. The book is presented just as it was left at the author's death, in October, 1884, with the carrying out of only a few examples in the twelve classes of girders still remaining to be done. Of these examples, the post-truss promised to yield the most prolific results; and it may be possible, the editor hopes, "before another edition is published, to complete this calculation at least, if not to introduce other examples from the later classes. However, the a priori method of the author is fully set forth previous to the tenth chapter; and it is believed that no one else has as yet published any so satisfactory results from this method, if, indeed, the method has been hitherto attempted with any degree of success." The work has been prepared for the press under the supervision of Professor John N. Stockwell, who has also undertaken the task of completing the remaining examples for future editions.
Bulletin of the United States Geological Survey. Nos. 21, 28, and 29. Washington: Government Printing-office. Pp. 80, 59, with Plates and Map, and pp. 24, with Plates.
No.27 is an account of the work done in the division of Chemistry and Physics, mainly during the year 1884-'85. Among the papers are one on "Topaz from Stoneham, Maine"; a memoir, by F. A. Gooch, on the
