Senior course in mechanical drawing
A late-nineteenth-century instructional manual in mechanical drawing by William H. Thorne, issued in Philadelphia by Williams, Brown & Earle in 1897 for advanced drafting students and apprentice engineers. The plates are line engravings of machine parts in section and plan, with hatched cutaways, centre lines, arrowed dimension lines, bolt-circle layouts and fractional-inch annotations that supply ready-made technical diagram vocabulary.
