Development of Natural Resources: The Coming Technological Revolution on the Land.

SCIENCE: A Weekly Journal, since 1900 the official organ of the American Association for the Advancement of Science. Published by the American Association for the Advancement of Science every Friday at Baltimore, Maryland. Editorial Advisers: W. L. Hart, Karl L. Darrow, Farrington Daniels, Otto Struve, H. R. Aldrich, George A. Baitsell, William Crocker, F. H. H. Roberts, Jr., Robert H. Seashore, Edward P. Hutchinson, Chauncey D. Leake, J. C. Hunsaker, W. J. Nungester, W. A. Albrecht, W. C. Olson, W. F. G. Swann. Communications relative to articles offered for publication should be addressed to Editor, 1515 Massachusetts Avenue, N.W., Washington 5, D. C. Communications relative to advertising and subscriptions should be addressed to THEO. J. CRsrnTzxszN, Mt. Royal and Guilford Avenues, Baltimore, and 1515 Massachusetts Avenue, N.W., Washington 5, D. C. Communications relative to membership in the Association and to all matters of business of the Association should be addressed to the Administrative Secretary, AAAS, 1515 Massachusetts Avenue, N.W., Washington 5, D. C. Annual subscription, $7.50 Single copies, 25 cents Entered as second-class matter July 18, 1923 at the Post Office at Lancaster, Pa., under the Act of March 3, 1879. (Application for re-entry to the second class of mail matter under the act of March 3, 1879, pending at Baltimore, Md.) Vol. 105