Revision powers of tax authorities permit review of subordinate orders, subject to notice, hearing and limitation safeguards. Powers of revision permit the Board and Commissioners to call for and examine records of proceedings and to pass orders to satisfy themselves as to the correctness, legality or propriety of decisions; they may act on their own motion or on application. Such revision orders cannot prejudicially affect persons without a reasonable opportunity to make representations and to be heard, and where recovery of excise duty is proposed a notice to show cause must be given within the prescribed time limit. Proceedings are barred after a limitation period from communication of the decision, and orders under these powers are appealable to the statutory appellate tribunal.