David Rittenhouse

A clockmaker by trade and a self-taught mathematician and astronomer, David Rittenhouse was second only to Benjamin Franklin as the foremost man of science in eighteenth-century America. His surveying instruments were unsurpassed; his astronomical calculations were solicited by almanac publishers near and far; and his orrery (a mathematically precise model of the solar system) was touted as the greatest mechanical wonder of the new world, more complete than anything that could be obtained in Europe. Rittenhouse's name, said physician and patriot Dr. Benjamin Rush, "gave splendor to the American character."

Charles Willson Peale painted his friend (and collaborator in experiments to improve rifles during the Revolution) seated before a large reflecting telescope-perhaps the one bequeathed to him by Benjamin Franklin-pointing to a comet in orbit.