Some experiments and observations on a new substance which becomes a violet-coloured gas by heat

The discovery now announced to the Society was made about two years since by M. Courtois, a manufacturer of saltpetre at Paris. It is procured from the ashes of sea-weeds: after the extraction of the carbonate of soda, the addition of strong sulphuric acid extricates this substance in the form of a violet vapour, which condenses in crystals, that have the colour and lustre of plumbago. The colour of its vapour has occasioned the French chemists to give it the name of iode, fromi ώ δ η s ,violaceous . Specimens of this substance were given to MM. Desormes and Clement, who have given a memoir upon it to the Imperial Institute, describing its principal properties. Its specific gravity is said to be about 4. It volatilizes at a temperature rather below that of boiling water. It combines with phosphorus, with sulphur, with metals, metallic oxides, and with alkalies, forming with ammonia a detonating compound. It dissolves in alcohol, or ether; and with hydrogen it forms a compound very similar to muriatic acid gas, but which M. Gay-Lussac, in a memoir read to the Institute, shows to be a peculiar acid, distinct from the muriatic: and he compares the body itself to oxymuriatic acid or chlorine; for, like that body, it may either be supposed simple, or thought to contain oxygen.