Announcement Concerning Publications of the National Research Council The Proceedings of the National Academy of Sciences is partly supported by the National Research Council which is represented officially on its Editorial Board and Executive Committee. It is open for the publication of papers to members of the National Research Council on the same terms as to members of the National Academy of Sciences. Subscription rate for the "Proceedings" is $5 per year. Business address: Home Secretary, National Academy of Sciences, Smithsonian Institution, Washington, D. C. The Bulletin of the National Research Council presents contributions from the National Research Council, other than proceedings, for which hitherto no appropriate agencies of publication have existed. (For list of bulletins see third cover page.) The "Bulletin" is published at irregular intervals. The subscription price, postpaid, is $5 per volume of approximately 500 pages. Numbers of the "Bulletin" are sold separately at prices based upon the cost of manufacture. (For list of reprints and circulars see fourth cover page.) The Reprint and Circular Series of the National Research Council renders available for purchase, at prices dependent upon the cost of manufacture, papers published or printed by or for the National Research Council. Orders for the "Bulletin" or the "Reprints and Circulars" of the National Research Council, accompanied by remittance, should be addressed: Publication Office, National Research Council, 1701 Massachusetts Avenue, Washington, D. C. E. W. BROWN, Professor of Mathematics, Yale University, Chairman; G. D. BIRKHOFF, Professor of Mathematics, Harvard University; REPORT OF THE COMMITTEE ON CELESTIAL MECHANICS Celestial mechanics, broadly interpreted, is involved in practi- cally all the astronomy of the present time. The limited meaning of the term now usually adopted refers only to those problems in which the law of gravitation plays the chief or only part, and more particularly to those which deal with the motions of bodies about one another and with their rotations. This limitation will, in any case, be adopted in this report since surveys dealing with other aspects of astronomy have been written or are contemplated. It is, however, necessary not to be too rigid about the border lines, especially in considering questions where the gravitational action does not fully account for the observed phenomena. The report has three general divisions: I, the solar system; II, the stellar system; III, the theoretical aspects of the general prob- lem of three or more bodies. It is not intended to contain a com- * The membership of the committee is: E. W. Brown, chairman, G. D. Birkhoff, |