The Inspector-General of Police shall be appointed a Justice of the Peace; he shall also have the full powers of a Magistrate throughout the General Police District, but shall exercise these powers subject to such orders as may from time to time be issued by the Governor in Council. The Governor in Council may vest any District Superintendent of Police with all or any of the powers of a Magistrate within such limits as he may deem proper; but such Superintendent shall exercise the powers with which he shall be so invested only so far as may be necessary for the peace, the prevention of crime, and the detection, apprehension, and detention of offenders in order to their being brought before a Magistrate, and as far as may be necessary for the performance of the duties assigned to him by this Act.