After a preliminary reference to the existence of fluorine in recent and fossil bones, Dr Wilson stated that he had made a series of experiments with a view to discover what solvent carried fluoride of calcium into the tissues of plants and animals. His first trials were made with carbonic acid, which was passed in a current through water containing pure fluor-spar in fine powder suspended in it. The fluor was by this treatment dissolved, yielding a solution which precipitated oxalate of ammonia, and when evaporated left a residue which, on being heated with sulphuric acid, gave off hydrofluoric acid.