Revisionary power: Commissioner may revise wealth-tax assessments based on valuation reports when valuation is palpably erroneous. A Commissioner may revise a wealth-tax assessment even if it is based on a valuation officer's report, because that report merges into the assessment order; revision is permissible where the report or assessment rests on irrelevant principles or a palpable mistake, with the existence of such error to be determined by the Commissioner.