{Edna Wadsworth; Heint Walentowsky; Gilbert T. Walker [folded]; O. R. Walkey; War Department [T. L. Coles; F. W. Coe]; J. G. Ward; Warner & Swasey Co.; Wasco County Library [Nina M. Moran]; Washburn College [Helen Whitaker]; Washburn Observatory [George C. Comstock]; Washington Academy of Sciences [Robert B. Sosman]; Washington, State College of [W. W. Foote]}
{Donald G. Marsh; Hannah Mary Marsh; Thomas Marshall, Jr. [folded]; Massachusetts Institute of Technology Library; Masson and Co.; T. M. Martin; T. Matukama; A. S. D. [Mrs. T. F.] Maunder; Thomas Frid Maunder; Oscar Maurer; R. Newton Mayall; Edward L. Mayberry; Carroll B. Merritt; W. F. Meyer; A. A. Michailovsky; G. R. Miczaika; Dayton C. Miller; Freeman D. Miller; H. L. Miller; John A. Miller; Mrs. John Miller}
{R. A. Millikan; Monroe Calculating Machine Co. [folded. incl Calculator Equipment Corp.]; Montevideo, Observatory of the University of [folded]; Monthly Weather Review; Joseph Monti; K. Moór [?]; Ernest C. Moore; Morava Construction Co.; D. W. Morehouse [incl ltr H. Shapley ? DWM]; D. P. Moreton; G. W. Morey; --Moriceau; T. H. Morgan; Sylvanus G. Morley; W. D. Morrison; Albert G. Mowbray [incl memo EPH ? FHS]; F. R. Moulton; Z. Müller; Carlos S. Mundt}
{G. B. Lal; Lancaster Press, Inc. [O. J. Smith, Jr.]; Hugo Landi; R. J. Lang; Sir Joseph Larmor; Jennie B. Lasby; Latvia University Astronomical Observatory, Riga [S. Slaucitajs]; G. Lecointe; H. Lehmann; Lemcke & Buechner; George H. Lepper; Sophia H. Levy; Lick Observatory; Bernhard Liebisch}
{John L. Ridgway; A. E. Riemer; T. K. Riggen; Philip S. Riggs; Augusto Righi; William E. Ritter; G. B. Rizzo; W. F. Roberts Co., Inc. [B. H. Roberts. folded]; H. P. Robertson}
{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}
