Herapathite, or iodoquinine sulfate, is a chemical compound whose crystals are dichroic and thus can be used for polarizing light.
Herapathite, or iodoquinine sulfate, is a chemical compound whose crystals are dichroic and thus can be used for polarizing light.
Its formation was investigated by 1852 by William Bird Herapath, a Bristol surgeon and chemist, after his pupil (Mr. W. H. Phelps) was attracted by some peculiarly brilliant emerald-green crystals that he noticed in a bottle containing a large quantity of the mixed disulfates of quinine and cinchonine. Herapath found that he could create these crystals by dropping tincture of iodine into a solution of quinine disulfate in diluted sulfuric acid and that, by studying the crystals under a microscope, that they polarized light very strongly. The story that a dog was involved in the discovery can be found in the widely quoted publication[2]. There appears to be no reliable evidence for it other than the article, nearly one hundred years later by E. H. Land.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).