If LorenTz derived the formula independently in 1870 he was obviously a bright lad As the linked Wikipedia article shows he was only born in 1853 Lorenz and his work are often confused with that of the more famous H A Lorentz In this case it might be a doubled attribution of a single derivation Note the closeness of dates 1869 and 1870 An alternative suggestion is that Lorenz the older man without a t first publicized the formula in 1869 e g at a physics conference and had it published the following year e g in a journal Further research could yeasay or naysay this The article may be derived from from The Hutchinson Encyclopedia September 22 2003 191 Words 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