Note 343 — COLOURED GLASS.—ARTIFICIAL GEMS.

[At the recent meeting of the British Association for the Advancement of Science, held at Cambridge (June 1845), M. Splittgerber exhibited specimens of glass into the composition of which gold entered as a chloride. These specimens were white, but upon gently heating them in the flame of a spirit-lamp, they became a deep-red. If again the same reddened glass is exposed to the heat of an oxygen blowpipe, it loses nearly all its colours, a slight pinkiness only remaining.]