Natiod ResearchCenters Walter Orr Roberts, President National Center for Atmospheric Res~nrch Associated Universities, Inc. (AU'I) John W. Firor, Director Gerald F. Tape, hresident UCAR Member Universities: Appendix F National Radio Astronomy Observatory University of Alaska David S. Heeschen, Director University of Arizona University California AU1 Member Universities: of The University of America Columbia University Catholic Cornell University University of Chicago Harvard University Colorado State University The Johns Hopkins University University of Colorado Massachusetts Institute of Technology Cornell University University of Denver University of Pennsylvania Princeton University Florida State University University of Rochester Harvard University Yale University University of Hawaii University of Illinois at Urbana- Association of Universities for Research Champaign in Astronomy, Inc. (AURA) The Johns Hopkins University Rupert Wildt, President University of Maryland Cerro To1010 Inter-American Observatory Massachusetts Institute of Technology Victor M. Blanco, Director University of Miami Kitt Peak National Observatory University of Michigan Leo Goldberg, Director University of Minnesota University of Missouri AURA Member Universities: New York University University of California State University of New York at Albany University of Chicago/University of Texas University of Oklahoma Harvard University Pennsylvania State University Indiana University Saint Louis University University of Michigan Texas A&M University The Ohio State University University of Texas Princeton University University of Toronto University of Wisconsin University of Utah Yale University University of Washington University of Wisconsin Cornell University W. Donald Cooke, Vice President for Research National Astronomy and Ionosphere Center Frank D. Drake, Director, Ithaca, N.Y. Tor Hagfors, Director, Observatory Operations, Arecibo, Puerto Rico For sale by the Superintendent of Dooaments,U.S. (fOVOmnIe nt Printing omm Washington, D.C. !2040!2- Price Sl.60 U.S. GOV2RNMLNT PRlNTlNG OPCICII: 1972 O-443-979 NATIONAL SCIENCE FOUNDATION WASHINGTON. D.C. 20550 POSTAGE AND FEES PAID OFFICIAL BUSINESS NATIONAL SCIENCE FOUNDATION .