under the Act of Assembly of Virginia, authorizing them to settle the rate of. exchange, at April term last, examined witnesses to prove the rate of exchange between Ireland and England. Irish is turned into English sterling by deducting one-thirteenth of the Irish, and English is turned into.Irish by adding one-twelfth of the English. See the record of April term, 1802, in the case of Mahon v. Grace’s Executors.