VIOLET-COLOURED GAS.
Put three or four grains of iodine into a small clean Florence oil flask, and close it with a cork. Warm the flask gently over a candle, or before the fire, and the iodine will become converted into a beautiful violet-coloured vapour, which condenses again into brilliant metallic crystals, when the flask is suffered to become cold. The experiment may be repeated with the same flask for any number of times.
Or, upon a small sheet of any metal, place a few grains of iodine, and add a chip of dry phosphorous; when the latter will inflame, and the iodine pass off in a violet vapour.