Scientific American, Vol. 30, No. 9 (1874)
Scientific American volume 30, number 9, published in 1874, is a weekly American periodical written for engineers, inventors and general readers of technical news. Its pictures are line engravings of mechanical devices: a pressure regulator with a stone-walled chamber, a cutaway of a boiler-like vessel filled with balls, a valve section, and a sloped pipe run with fittings. A designer could draw on their precise hatching, cutaway conventions and clean numbered callouts for technical diagrams.
