Scientific American, Vol. 6, No. 20 (May 1862)
A weekly issue of Scientific American, the New York patent and invention journal published by Munn & Co. in May 1862 for inventors, engineers, and mechanics during the Civil War. The wood engravings are small technical diagrams — gear trains and cranks on timber posts, gun carriages in casemate embrasures, lettered part keys, and sectional views drawn as fine hatched line over grey tone — useful as machine-part silhouettes, diagram callouts, or period patent-drawing texture.
