Creator
- Peterson, Peter1
- Philadelphia Board of Trade1
- Phillips, Professor1
- Piper, Jason1
- Platt & Brother1
- Poggendorff, J. C. (Johann Christian), 1796-18771
- Post, C. W.1
- Potter, C. M.1
- Pugh, Evan, 1828-18641
- Quay, Matthew Stanley, 1833-19041
- Rand, B. Howard (Benjamin Howard), 1827-18831
- Read, Zach1
- Reese, William S.1
- Remsen, Ira, 1846-19271
- Rensselaer Polytechnic Institute1
- Richardson, William A. (William Adams), 1821-18961
- Ringwalt, J. Luther (John Luther)1
- Robertson, Andrew1
- Robinson, David1
- Roemer, H.1