| Packard, Alpheus Spring, Jr. |
0385, 0408, 0491, 0492, 0628, 0708 |
| Page, Charles G. |
0284 |
| Paleontological Society |
0884 |
| Palmer, Edward |
0439 |
| Park, William Hallock |
0684, 0753 |
| Patterson, Robert |
0061 |
| Payne, William W. |
0667 |
| Peabody Academy of Science |
0405 |
| Peale, Charles Willson |
0032, 0051, 0279 |
| Peale, Rembrandt |
0032 |
| Peale, Titian R. |
0097, 0111, 0133 |
| Peary, Robert E. |
0905 |
| Peirce, Benjamin |
0226, 0257, 0296, 0307, 0314, 0333, 0380, 0404, 0431 |
| Peirce, Charles Sanders |
0431, 0436, 0506 |
| Penington, John |
0007 |
| Pennsylvania Horticultural Society |
0140 |
| Perrine, Charles Dillon |
0823 |
| Petrologists' Club |
0920 |
| Pharmacopoeial Convention |
0114 |
| Phelps, Almira Hart Lincoln |
0148, 0172 |
| Philadelphia Journal of the Medical and Physical Sciences |
0113 |
| Philadelphia Medical and Physical Journal |
0052 |
| Philadelphia Society for Promoting Agriculture |
0136 |
| Phillips, John C. |
0896 |
| Physical Review |
0688 |
| Pickering, Edward Charles |
0465, 0574, 0666, 0798, 0872 |
| Pickering, William Henry |
0666, 0737 |
| Pierce, George Washington, |
0923 |
| Pirsson, Louis V. |
0800 |
| Poinsett, Joel R. |
0211, 0241 |
| Popular Astronomy |
0686 |
| Popular Science Monthly |
0452 |
| Porter, Rufus |
0247 |
| Pourtales, Louis Francois de |
0278, 0432, 0442, 0447 |
| Powell, John Wesley |
0416, 0429, 0472, 0497, 0508, 0531, 0615, 0795, 0871 |
| Priestley, Joseph |
0008, 0012, 0017, 0049 |
| Princeton University |
0014, 0460 |
| Prudden, Theophil Mitchell |
0585 |
| Psychological Review |
0696 |
| Pumpelly, Raphael |
0459 |
| Pupin, Michael I. |
0715 |
| Pursh, Frederick |
0033, 0051, 0078 |
| Putnam, Frederic Ward |
0385, 0408 |
| Q |
| Queeny, John Francisco |
0770 |
