Smith Thompson,
United States v. Wood (39 U.S. 430…
“ The rule, as we find it laid down in the elementary books on this subject, is, that to convict a party of the crime of perjury, two witnesses are necessary to contradict him as to the fact upon which the perjury is assigned: and the reason assigned for the rule is, that if one witness only is produced, there will only be one oath against another. This rule, however, in the early adjudged cases, was so modified as to require but one living witness, corroborated by circumstances, to contradict the oath of the defendant ”
