In order to facilitate the acquisition of property as defined in this article, and which, in the judgment of the corporation, will be in the public interest and necessary for canal purposes, payment for such property may be made by means of an exchange therefor of property found to be no longer necessary or useful as a part of the barge canal system, or as an aid to navigation thereon, or for barge canal terminal purposes. The property to be so acquired shall be of at least equal value to that of such property to be exchanged. The corporation is authorized and empowered to enter into an agreement with the owner or owners of such property to be so acquired, upon such terms and conditions as to such corporation shall seem appropriate and proper to accomplish such purpose. In all such cases, the property so to be exchanged shall first be declared abandoned by official order of the corporation which order shall set forth the benefits to be obtained by such exchange. In such abandonment it shall be unnecessary to conform to the provisions for abandonment made in § 51 (Method of abandonment)section fifty-one of this chapter. The agreement and the title to the property to be acquired shall be subject to the approval of the attorney-general. Upon the approval of title by the attorney-general, the corporation is authorized and empowered to execute in the name of the people of the state of New York, a quit-claim deed to effectuate such exchange, which shall be subject to the approval of the attorney-general. The deed so executed, before becoming effective, shall be recorded in the office of the secretary of state. Compensation on account of excess value if any, of the lands so acquired shall be adjusted and paid in the manner provided by § 40 (Acquisition of property)section forty of this article, as in the case of property taken by appropriation.