Iridium was discovered and named by a British scientist, Smithson Tennant. About 1800 he began an extended association with W. H. Wollaston in London for the purpose of improving the technology of the fabrication of platinum. This metal had for some time been known to dissolve almost completely in aqua regia, but a small black residue always remained and was for a time thought to be graphite. In the summer of 1803 Tennant began a study of this material which ultimately resulted in the identification of both osmium and iridium