 He mentioned in his "Personal Narrative" that his friend William Brockedon invented the word vulcanisation from the god Vulcan of Roman mythology.Hancock did not credit himself with discovering the reaction of sulphur with rubber; he instead said that in 1842 Brockendon had showed him some American rubber samples which had been treated with sulphur.Brockendon later said in an affidavit that he never heard or knew of Hancock analysing the Goodyear samples, a claim Hancock verifies in his "Personal Narrative", where he claimed he had been experimenting with sulphur for many years himself.