{Aug. Collard; T. Collodi; F. Barrows Colton; Commission for Russian Scientists; A. Pribar de Conill; Duvall Cooper; Copernicus 450th Anniversary; Corning Glass Works; A. L. Cortie, S.J.; Robert Coughran; G. Cramer Dry Plate Co.; R. T. Crawford; Henry Crew; Raymond E. Crowtherb [Kodak, London]; James Cuffey}
{T. C. Chambelin; C. A. Chant; G. A. Clark; W. W. Coblentz; A. Cotton; R. T. Crawford; Henry Crew; J. Danne; Arthur L. Day; H. Deslandres; A. Donner; F. W. Dyson; H. Ebert; Mrs. W. P. Fleming; E. Gehrcke; H. M. Goodwin; D. Goldhammer}
{Fr. R. Cirera, S.J.; Cpt. P. Civalleri, R.I.N.; Civic Bureau of Music and Art of Los Angeles; Claremont Colleges; Nell Ray Clarke; --Clasen; Gerald Coffman}
{California State Library; José da Silveira Camerino; Francis A. Campbell; Léon Cap; R. Stanley Capon; Ellsworth Carpenter; F. E. Carr; Carter Observatory [R. C. Hayes]; S. Chapman; Rev. Stanislaus Chevalier, S.J.; Christian Science Monitor [Robert K. Shellaby]; Christiania University Observatory}
{Dorothy N. Davis; Dartmouth College, Baker Memorial Library; L. P. Delsasso; Denver Public Library; Debrecen University Physical Institute; Rev. C. E. Deppermann, S.J.; Detroit Public Library; Deutsche Physikalische Gesellschaft; Deutsches Museum; L. E. Dickson}
{Clara Robinson; Ruth Stone [Mrs. C. C.] Robinson; Rev. Luis Rodés, S.J.; Guy Rose; H. Rosenberg; Royal Institution, London; Royal Society of Edinburgh; Royal Society of London; Walter Russell; Ryerson Physical Laboratory; P. M. Ryves}
{Charles L. Limes; E. M. Lindsay; Charles B. Lipman; Charles G. Little; L. C. Lonyo; Rafael Obregon Loria; Los Angeles Board of Park Commissioners; Los Angeles Civic Bureau of Music and Art; Los Angeles Times [G. L. Goodmansen]; Hazel Marie Losh; Katheryn Lowe [incl ltr Irving M. Grey ? FHS]; Percival Lowell; Robert L. Lucas; --Luppo-Cramer; Lwow Astronomical Institute}
