Institutes of natural philosophy, theoretical and practical
A physics and astronomy textbook by the English dissenting minister William Enfield, first issued in the 1780s and reprinted for American college students in Boston in 1824. The plates are folding sheets of engraved line diagrams — numbered figures showing levers, inclined planes, force parallelograms, lens and mirror ray traces, circles and angled construction lines — printed thin and brown on foxed paper, useful as geometric line stock, ray-diagram motifs, or aged paper texture.
