Set of five varnished cardboard drawing and indicator diagram scales by John Lockie, Leith. No 2. is missing. In a cardboard case.

A set of six scales, one missing (No 2). The scales numbered 1-5 are regular imperial scales of various inches to the foot including 4 inches to the foot, 1/2 inch to the foot and 3/8 of an inch to the foot. The scale numbered six is an indicator diagram scale giving figures for engine indicator diagram papers and showing pounds, pressure. (An engine indicator is the engineer's equvialent of a stethsocope giving the varying pressures within a cylinder during one revolution or in a four stroke cylinder, in two stroke revolutions). The price of the set (1 shilling, 6 pence) indicates they were bought and used by students.