Lorentz-Lorenz relation

In physics, the Lorentz-Lorenz law relates the index of refraction n and the density &rho; of a dielectricum

\frac{n^2-1}{n^2+2} \propto \rho $$

The relation is named after the Dutch physicist Hendrik Antoon Lorentz and the Danish physicist Ludvig Valentin Lorenz.