Convert from chain [Ramsden, engineer] to bohr

Unit Definition (chain [Ramsden, engineer])
The Ramsden chain is quite different to the Gunter chain. The Ramsden chain was commonly used by American surveyors. It equals approximately 100 feet and is also known as the engineer's chain.

Unit Definition (bohr)
The Bohr is a unit of distance commonly used in particle physics. It was named after the Danish physicist Niels Bohr (1885-1962), who explained the structure of atoms in a famous paper in 1913. The Bohr radius represents the mean distance between the proton and the electron in an unexcited hydrogen atom. It equals about 52.918 picometers (pm), or 52.918 x 10e-12 meter.