DIVIDERS AND COMPASSES.
These instruments, while they appear alike, have a separate use: the dividers are used to space off distances and dimensions; especially are they necessary in reading drawings made to scale. Compasses are used for describing circles, curves, etc., dividers are used for marking out spaces.
Two forms of the dividers are shown in [figs. 169 and 170]; the simplest, plainest form is shown in [fig. 169]; these are used for rough spacings; [fig. 170] represents a pair of dividers fitted with an adjustable screw controlled by a steel spring in one leg; by this a very exact measurement can be made. [Fig. 170] is intended to exhibit what is called a “hair-spring divider.”