{Nikolayev Astronomical Observatory [L. Semenov]; Nixdorf Observatory; Charles A. Noble; Gladys Noon; H. Nort; Norwegian Meteorological Institute [folded]; Werner Nowachi; Arthur A. Noyes}
{Herbert Dingle [lecture & notes by FHS on "Science and the Unobservable"]; Harold B. Dirks; Roberta Lloyd [Mrs. Hugh T.] Dobbins [re S. Pike's grave]; Dorpat University Meteorological Observatory; E. Doublet; John C. Duncan; R. S. Dugan; Theodore Dunham, Jr.; Theodore Dufur; O. L. Dustheimer}
{The Neuner Co.; New Hampshire, University of [George N. Bauer]; News Chronicle [Robert Waithman]; Newton & Co., Ltd. [A. J. Batchelor]; New York Public Library [R. J. Lingel]; New York State Library [Gladys T. Jones]; Mrs. Wanda Sheldon Nichols; Seth Barnes Nicholson; A. A. Nijland}
{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}
{A. O. Tait; Tashkent Astronomical Observatory; A. Tass; Taylor and Francis; Taylor Instrument Cos.; Taylor, Taylor, & Hobson, Ltd.; Robert J. Teall; Jan Teders; B. G. Teubner; A. David Thackeray; O. Thomas; W. Irwin Thompson; --Thorndike; E. R. Thorwarth}
{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}
{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}
