Report of an examination of railroad men for color blindness : read before the Pennsylvania State Medical Society, May 22nd, 1879
A report by Peter Dirck Keyser, read to the Pennsylvania State Medical Society in 1879, on testing railroad workers for colour blindness, probably printed in Philadelphia. The picture is a plate of a curved, rounded wooden or leather-like shape with a row of small studs or rivets, shown beside a hand, with a blue library stamp in the corner that a designer can ignore. The engraved forms are plain and mechanical, with clean hatching and a tactile, sculptural quality that could suit industrial or instructional graphics.
