All Bones Considered: Laurel Hill Stories #043: Henry & Thomas Voigt, Isaiah Lukens & Henry Seybert – Tick Tock, Clocks and Watches, part 1, section 3

Isaiah Lukens not only built clocks that can still be seen at The Athenaeum and the Germantown City Hall, but he also built an air gun that may have been used by Lewis & Clark during their expedition.