“ For his time he was a skilful chemical analyst; he knew how to distinguish potash and soda by the different colorations they produce in flame, and how to test for iron with prussiate of potash: he was aware that sulphate of potash, gypsum and heavy spar, in spite of their different appearances, all contain sulphuric acid; and he recognized that there are different varieties of urinary calculi. In metallurgy he devised improved methods for the manufacture of zinc and the purification of silver, tin and other metals. ”