Tax concession for profits from industrial undertakings, hotels and ships tied to prescribed return on capital and eligibility tests. Section 84 is amended to exempt from income-tax profits and gains derived from an industrial undertaking, the business of a hotel, or from a ship up to a prescribed return on capital employed, with eligibility conditioned on commencement, ownership, employment and prescribed standards; limited transfers of previously used assets are disregarded for capital computation; rented premises and specified re-establishment circumstances do not defeat conditions; and ships meeting ownership, prior-use and commencement tests are included with specified assessment-year application.