Unpublished letter, 'Observations on the changes which have taken place in some antient [ancient] alloys of copper' from John Davy to Sir Humphry Davy Davy describes his experiments and observations on ancient copper alloys from Greece, including a bronze helmet found in the sea, coins, and a mirror found in a tomb. He describes his physical and chemical examinations of the alloys. The manuscript is incomplete and stops mid-sentence. Subject: Chemistry Received by the Royal Society on 20 June 1825. [1825]