A short auxiliary scale placed beside the main scale on a measuring instrument to enable subdivisions of the main scale to be read accurately. The vernier scale is usually calibrated so that each of its divisions is 0.9 of the main scale divisions. The zero on the vernier scale is set to the observed measurement on the main scale and by noting which division on the vernier scale is exactly in line with a main scale division, the second decimal place of the measurement is obtained (see illustration). The device was invented by Pierre Vernier (1580–1637) in about 1630.
Vernier scale
- radiography
- radioisotope
- radioisotope imaging
- radiolocation
- radiology
- radiolysis
- radiometric dating
- radionuclide
- radiosonde
- radiotherapy
- radiotransparent
- radium
- radius of curvature
- radius of gyration
- radius vector
- radon
- rainbow
- RAM
- Raman effect
- ramjet
- Ramsay, Sir William
- Ramsden eyepiece
- random alloy
- random walk
- Rankine cycle