Lorenz, Ludwig Valentin (1829–1891)

Danish mathematician and physicist. He developed mathematical formulae to describe phenomena such as the relation between the refraction of light and the density of a pure transparent substance, and the relation between a metal's electrical and thermal conductivity and temperature.

Lorenz was born in Elsinore and studied at the Technical University in Copenhagen. He became professor at the Military Academy in Copenhagen in 1876. From 1887 his research was funded by the Carlsberg Foundation.

He investigated the mathematical description for light propagation through a single homogeneous medium and described the passage of light between different media. The formula for the mathematical relationship between the refractive index and the density of a medium was published by Lorenz in 1869 and by Hendrick Lorentz (who discovered it independently) in 1870 and is therefore called the Lorentz–Lorenz formula. Using his electromagnetic theory of light, Lorenz was able to derive a correct value for the velocity of light.