Scientific American, Vol. 26, No. 25 (June 1872)
Scientific American was a weekly illustrated periodical published in New York by Munn & Co., and this June 1872 issue reports patents and industrial processes for inventors, mechanics, and technically curious readers. Its wood engravings are figure-numbered mechanical diagrams — cutaway sections through valves and spindles, gear and pulley trains, a graduated gauge scale — with dashed hidden lines, letter callouts, and hatched cut surfaces usable as technical line stock.
