Sentence:  Many of these coins are preserved at the British Museum, in London, and at the  Ashmolean Museum, in Oxford, and are all of pure gold, without <WSD>alloy</WSD>, and in a  good state of preservation. Boadicea, Queen of the Iceni, is also said to have... 
Meaning of the word marked with <WSD> tags:  A metal of lesser value, mixed with a metal of greater value.