Upon all money due under a mortgage under this Act being fully paid the F2Treasury shall, when required, give in the prescribed manner to the person liable to the payment thereof a receipt in writing for the same, and such further sufficient discharge (if any) as may seem to the F2Treasury to be necessary, and upon such receipt being given the mortgaged rate shall be released from the charge and the mortgaged property, or the part thereof not sold or disposed of under this Act, shall (unless the F2Treasury, on the request and at the expense of the person paying the said money, make any other disposition thereof,) revest in the person who would have been entitled thereto if the mortgage had not been made, subject nevertheless to any lease, mortgage, or other act previously made or done by or under the direction of the F2Treasury.