A multi-scale mechanism comprising a rotatable driving shaft; a first scale mounted along the axis of said rotatable driving shaft, said scale including first and second sets of coarse scale divisions for indicating a coarse range of magnitude in two different systems of units as a function of the position of said first scale with respect to said rotatable driving shaft; a second scale for indicating a fine scale range of magnitude in one of said systems of units; a third scale for indicating a fine scale range of magnitude in the other of said systems of units; said third scale operatively connected to said rotatable driving shaft; and a gear assembly coupled to said rotatable driving shaft and connected to said second scale and said third scale, said gear assembly having a predetermined gear ratio such that said second scale and said third scale are each caused to move at the same time but at a different rate that is a function of their respective system of units.