...books concerning the practices to which the action which he has determined to bring relates, and it shall be the duty of the Justice of the supreme court...application. The application for such order made by the attorney general may simply show upon his information and belief that the testimony of such person...

...United States attorney for the District of Columbia may simply show upon his information and belief tint the testimony of such person or persons is material and necessary. The order shall l>e granted by the justice of said supreme court to whom the application has been made...