"Ludvig Valentin Lorenz (/ˈlɒrənts/; 18 January 1829 – 9 June 1891) was a Danish physicist and mathematician. 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 (Wiedemann–Franz–Lorenz law)." - (en.wikipedia.org 11.08.2021)