Elementary natural philosophy : designed for high schools and academies
A physics textbook by La Roy F. Griffin, published in Philadelphia by Sower, Potts & Co. in 1881 for high school and academy students. Wood-engraved figures show laboratory apparatus — galvanometers, mercury barometers, dial-faced instruments on turned stands — alongside white-on-black optical ray diagrams with lettered points, offering compact instrument silhouettes and line-and-arrow geometry for reuse.
