INTERCHANGEABLY. Formerly when deeds of land were made, where there Were covenants to be performed on both sides, it was usual to make two deeds exactly similar to each other, and to exchange them; in the attesting clause, the words, In witness whereof the parties have hereunto interchangeably set their hands," &c., were constantly inserted, and the practice has continued, although the deed is, in most cases, signed by the grantor only. 7 Penn. St. Rep. 320.