Letter from Henri Morisson, 7 Rue Vauquelin, Paris, to Mr [Alan Archibald Campbell] Swinton, 66 Victoria Street, London, S.W. Thanking Swinton for sending him his publication on X rays and regrets he cannot send him a fragment of metallic uranium. Informs he is conducting experiments on the subject of the transparency of uranium and is in the process of having thin sheets prepared, which is presenting some difficulties. 17 October 1897