TY - JOUR T1 - On the Law of Extraordinary Refraction in Iceland Spar JF - Proceedings of the Royal Society of London (1854-1905) VL - 20 SP - 443 EP - 444 PY - 1871/01/01/ UR - http://dx.doi.org/10.1098/rspl.1871.0088 M3 - doi:10.1098/rspl.1871.0088 AU - Stokes, G. ER -