{H. Kienle; M. F. Kimball; Mrs. W. L. Kinney; Otto Knopf; H. Knox-Shaw; Kobe Imperial Marine Observatory; K. F. Koehlers Antiquarium; --Konkoly; Kosmos; Kranseder & Co., Gmbh; Jan Krassowski; --Krater; Adolf Krause; C. J. Krieger; Hillier Krieghbaum; A. F. Kuhlman}
{--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]}
{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}
{Halbert P. Gillette; Curvin H. Gingrich; F. Gonnessiat; Katharine Gordon; W. B. Gordon; Göttingen Observatory/Library; Lucien Gougy; L. Grabowski; Carlos Graef [Fernández]; K. Graff; John Grant; Graphic Arts Press [J. Stuart Lynch]; W. de Groot; George R. Grose; H. Grouiller; Frederick O. Grover [re extra-terrestrial life]; F. A. Guth}
{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}
{L. Gabba; Galileo Portrait [Charles E. Lewis]; Joaquín Gallo; H. A. Garfield; Willard H. Garrett; G. N. Garrison; General Petroleum Corp. of California; Georgia Astrophysical Observatory; F. Louise Gianetti; Henry L. Giclas; Millicent Gilder}
{Oberlin College [F. E. Carr; Emma L. Frank]; Sir Frederick O'Connor; J. Ogden; R. M. Ogden; Yngve Öhlman; Eleanor Olney; John Ohlsson; William Tyler Olcott [& G. H. Lutz]; Charles P. Olivier; P. Th. Oosterhoff; Earle L. Ovington}
