This is a slide and lecture presentation, prepared by Stephen Kramer, on the Rittenhouse orreries at the University of Pennsylvania and Princeton University. Included is a transcript of the lecture (APS Archives 8/14/81).

Robert Maskell Patterson (1787-1854, APS 1809) was a professor of chemistry and natural philosophy at the University of Pennsylvania (1812-1828) and professor of natural philosophy at the University of Virginia (1828-1835). He was director of the U.S. Mint from 1835 to 1851. His father, Robert Patterson, was a revolutionary soldier, professor of mathematics at the University of Pennsylvania (1779-1814), and director of the U.S. Mint (1805-1824).