309. In the case of any of the persons mentioned in article 311, any powers which, if such person were a person of unsound mind so found by inquisition under the provisions of the Lunacy Act, 1890 (3 & 4 Vict. c. 5) could be exercised by the committee of the estate, may be exercised by such person in such manner and with or without security, as the Judge subject to rules of Court, may direct, and any such order may confer on the person therein named authority to do any specified act or exercise until further order all or any of such powers without further application to the Judge.