Convert from chain [Ramsden, engineer] to hair's breadth

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 (hair's breadth)
The hair's breadth is a common informal unit of distance. Human hairs vary considerably in width, depending on age, color, genetics, and other factors. An average hair is approximately 70 to 100 micrometers (µm) in diameter, so, as a rough standard, a hair's breadth is 100 µm or 0.1 millimeter (mm).