Template:Are You Sure/May 22

• ... that mineralogist, physicist, and mathematician [Franz Ernst Neumann (nonfiction)|Franz Ernst Neumann]] (1798–1895) deduced laws of double refraction closely resembling those of Augustin-Jean Fresnel, and that Neumann subsequently contributed to the mathematical expression of the conditions holding for a surface separating two crystalline media, working out from theory the laws of double refraction in strained crystalline bodies?