{W. M. Smart; Albert M. Smith; Ruth Emily Smith; Sinclair Smith; Smith Premier Typewriter Co.; Smithsonian Institution; Edwin R. Snyder; Sociedad Astronómica de España y América; Società Astronomica Italiana; Société Astronomique de France; Société Francaise de Physique; Society of Writers to H. M. Signet}
{Ibérica; Indian Academy of Sciences [M. N. Saha]; Institut d'Astronomique Pratique, Warsaw, Poland; Institut d'Optique; Institut de Physique du Globe, Paris [Ch. Maurain]; Institute of International Education; International Catalogue of Scientific Literature; International Education Board [re grant for AAVSO]; International Magazine Co.; International Press Service; Irving-Pitt Manufacturing Co.; Dorothea Isaac-Roberts}
{C. E. Adams; Hans Christian Adamson; Agence de Libraire et de Publications; Dinsmore Alter; American Academy of Arts and Sciences; American Astronomical Society [Raymond Smith Dugan]; American Council on Education; American Mathematical Society [Marc H. Ingraham]; American Offset Printers; American Telescope Laboratories, Inc.; Genevieve Arduin; Merle Armitage; Associated Press; Association of Colleges and Universities of the Pacific Southwest [Charles T. Fitts; Ernest J. Jaqua]; J. Attarablas; Audiphone Co.; Automobile Club of Southern California. folded}
{Sigma Xi; L. Silberstein; Edward E. Simonds; Frederick Simpich; Arthur W. Sinclair; A. de Sitter; W. T. Skilling; Sarah Louise Slaughenhaup; Paul Slavenas; Frederick Slocum; E. E. Slosson}
{Science Press; Science Progress; Scientia; Scientific American; Scientific International Research Service Corp.; E. M. Scofield; Charles Scribner's Sons; N. P. Scudder; H. von Seeliger; Seismological Society of America; Selznick International Pictures, Inc. [W. E. McCune]; Service; Geneva Seybold; James A. Shanahan; W. N. Shaw; Barbara Sheffield}
{Ukrainian SSR Academy of Sciences; USSR Society of Cultural Relations with Foreign Countries [E. Tsubina; I. Korinetz; M. Apletin; E. Leite; M. Milikovsky]; US Civil Service Commission; US Coast and Geodetic Survey; US Customs Service; US Department of Commerce; US Geological Survey; US Naval Observatory; US Shipping Board; US Weather Bureau; Universal Film Manufacturing Co. [M. G. Jonas]; Université Libre de Bruxelles [R. Sedeyn]; University of California at Los Angeles [Frederick C. Leonard]; University of Utah [Junius J. Hayes]; University of Washington Library [W. E. Henry]; Universum Book Export Co., Inc.}
{--Kammerlingh-Onnes; "Kapteyn Cottage"; B. Karpov; Katherine P. Kaster; Kasan University Astronomical Observatory; Katherine P. [Mrs. H. B.] Kaster; J. Kater; Heinrich Kayser; C. H. Kelley; Hugh J. Kelly; Roy J. Kennedy; Norton A. Kent; Frederick P. Keppel; M. de Kerolyr; Keystone View Co. of New York, Inc. [F. Lorenz]}
