| Cabell, James L. |
0533 |
| California Academy of Sciences |
0319 |
| California State Earthquake Investigation Commission |
0890 |
| Calkins, Gary Nathan |
0768 |
| Cambridge Miscellany of Mathematics, Physics and Astronomy |
0226 |
| Campbell, William Wallace |
0709, 0918 |
| Cannon, Annie Jump |
0641, 0710 |
| Cannon, Walter Bradford |
0882 |
| Carleton College |
0686 |
| Carnegie Foundation |
0907 |
| Carnegie Institution of Washington |
0788, 0802, 0815, 0826, 0842, 0847, 0848, 0863, 0919 |
| Carrel, Alexis |
0824 |
| Carroll, James |
0754 |
| Carus, Paul |
0649.5 |
| Castle, William Ernest |
0896 |
| Catherwood, Frederick |
0215 |
| Cattell, James McKeen |
0618, 0696, 0703, 0760, 0842 |
| Centennial Exhibition (Philadelphia) |
0487 |
| Central High School, Philadelphia |
0191 |
| Chamberlain, Alexander F. |
0672 |
| Chamberlin, Thomas Chrowder |
0560, 0687, 0829 |
| Chandler, Abiel |
0309 |
| Chandler, Charles F. |
0488 |
| Chandler, Seth Carlo |
0548, 0657 |
| Chapman, Alvan Wentworth |
0360 |
| Chapman, Frank Michler, |
0745 |
| Chapman, Nathaniel |
0113 |
| Charleston Botanic Garden and Society |
0053 |
| Chemical Abstracts |
0701 |
| Chemical Society of Philadelphia |
0007, 0034 |
| Chesapeake Zoological Laboratory |
0520 |
| Chicago Academy of Sciences |
0337 |
| Chittenden, Russell Henry |
0480, 0792 |
| Cincinnati Astronomical Society |
0225 |
| Cincinnati Observatory |
0425 |
| Clapp, Cornelia M. |
0620 |
| Clark University |
0672 |
| Clark, Alvan |
0312, 0601 |
| Clark, Alvan G. |
0726 |
| Clark, William |
0051 |
| Clarke, Frank Wigglesworth |
0877 |
| Cleaveland, Parker |
0087, 0106 |
| Clements, Frederic Edward |
0894 |
| Clinton, DeWitt |
0082 |
| Coffin, James H. |
0317 |
| Cold Spring Harbor Laboratory |
0648 |
| Cole, Leon Jacob |
0776, 0916 |
| Colt, Samuel |
0185 |
| Columbia University |
0033, 0461, 0632, 0743 |
| Columbia University School of Mines |
0389 |
| Columbian Chemical Society |
0007 |
| Columbian Institute for the Promotion of Arts and Sciences |
0088, 0211 |
| Comstock, Anna Botsford |
0630, 0706 |
| Comstock, John Henry |
0630, 0706 |
| Connecticut Academy of Arts and Sciences |
0026 |
| Connecticut agricultural experiment station |
0473, 0635 |
| Conrad, Timothy A. |
0156, 0171, 0184 |
| Cooke, Josiah Parsons, Jr. |
0323, 0388, 0410 |
| Coolidge, William David |
0917 |
| Cooper, Curtice |
0683 |
| Cooper, Thomas |
0008, 0065, 0075, 0086, 0205 |
| Cope, Edward Drinker |
0395, 0413, 0438, 0476, 0532, 0567, 0712, 0730 |
| Cornell University |
0593, 0617, 0688, 0718 |
| Coues, Elliott |
0453, 0566 |
| Coulter, John Merle |
0477 |
| Coxe, John R. |
0075 |
| Crile, George Washington |
0832 |
| Cross, Charles Whitman |
0800, 0920 |
