Weighing scale
The balance (also balance scale, beam balance and laboratory balance) was the first mass measuring instrument invented. In its traditional form, it consists of a pivoted horizontal lever with arms of equal lengththe beamand a weighing pan suspended from each arm (hence the plural name ""scales" for a weighing instrument). The unknown mass is placed in one pan and standard masses are added to the other pan until the beam is as close to equilibrium as possible. In precision balances, a more accurate determination of the mass is given by the position of a sliding mass moved along a graduated scale. Technically, a balance compares weight rather than mass, but, in a given gravitational field (such as Earth's gravity), the weight of an object is proportional to its mass, so the standard masses used with balances are usually labeled in units of mass (e.g. g or kg).
Multi-scale fingerboard
Possibly the first modern multiscale fretboard was used on an instrument called a StarrBoard, invented by John D. Starrett in 1977. Starrett developed a tapping instrument that employs a matrix of halftones, fretted horizontally with strings spaced vertically, to allow one fingering to cover all scales. Because of the large range of notes from low B below E on a bass, to high B four octaves above, however, he needed a way to have a long scale for the low B, but a shorter scale for the high B. He simply laid out the two scales he thought would work and connected the dots.