Calipers were first appeared in China, however, Pierre Vernier invented the "graduated" caliper. Pierre Vernier’ father was a lawyer and engineer (1584-1683) and taught him mathematics and science. Pierre Vernier worked on cartography and on surveying. His interest in surveying led to developing instruments for surveying and this prompted the invention for which he is remembered by all scientists, the "graduated" vernier.In his book he describes his most famous invention, that of the vernier caliper, an instrument for accurately measuring length. There are two graduated scales on it, a main scale like a ruler and a second scale that slides parallel to the main scale and enables readings to be made to a minute fraction of a division on the main scale.
Calipers with a dial are much easier to read than the old dial-less slide vernier calipers.They eliminate the eye strain. Always double check a caliper reading! Vernier calipers with a dial can jump a setting.
It is very important for us to store the dial vernier calipers in a dry, humid free location, and checked often for correct calibration. They can be wiped off with oil, but any build-up of oil will collect dirt. Additionally, the tips should be checked for wear. Digital calipers are becoming more popular, probably because they have less tendency to skip gears. Digital vernier calipers are very accurate and the batteries last a long time on most brand units.