IT is reported that at Monday's meeting of the; Paris Academy of Sciences Prof. Lapparent described some experiments by Prof. Bordas upon the conversion of corundum into precious stones by the influence of radium. It is stated that when fragments of corundum were placed in contact with a tube containing radium for a month they changed colour entirely, and were transformed into crystalline varieties of the mineral, some pieces becoming yellow, like topaz; others purple, like amethyst; blue, as sapphire; and red, as rubies. The gems thus produced were submitted to a jeweller, who was unable to distinguish them from precious stones. We shall await with interest the appearance of the Comptes rendus of Monday's meeting for particulars of these experiments and results.

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