Steam engine indicators and valve gears;
A 1918 technical manual by Llewellyn V. Ludy, issued in Chicago by the American Technical Society for machinists, engineers, and correspondence students learning to read indicator diagrams and set valve gear. The 138 plates are line engravings: sectioned steam cylinders with pistons and ports, crank circles drawn in dashed construction lines, eccentric and linkage diagrams, and plan views of indicator drums, all in black on tinted stock with lettered reference points.
