PURPOSE OF THE INDICATOR.
In the course of these pages, reference has several times been made to the indicator. This instrument is of great service to the steam engineer in helping him to determine with accuracy questions of steam distribution, that, without its aid, would remain in the realms of speculation. Its diagram presents a reliable record of what is going on inside the cylinders of a steam engine; and master mechanics who desire to run their engines economically, can not afford to dispense with the accurate information imparted by the indicator respecting individual locomotives.