assessee; (c) in the case of machinery or plant, to twenty per cent of the cost thereof to the assessee; Provided that 765 (c)the aggregate of all allowances in respect of depreciation made under this clause and clause (vi a) or under any Act repealed hereby, or under the Indian Income Tax Act, 1886 (II of 1886), shall, in no case, exceed the original cost to the assessee of the buildings, machinery, plant or furniture, as the case may be; (vi a) in respect of depreciation of buildings newly erected, or of machinery or plant being new which has been installed, after the 31st day of March, 1948, a further sum (which shall be deductible in determining the written down value) equal to the amount admissible under clause (vi) (exclusive of the extra allowance for double or multiple shift working of the machinery or plant and the initial depreciation allowance admissible under that clause for the first year of erection of the building or the installation of the machinery or Plant) in not more than five successive assessments for the financial years next following the previous year Sup/69 14 766 in which such buildings are erected and such machinery and plant installed and falling within the period commencing on the 1st day of April 1949 and ending on the 31st day of March, 1959; (vi b) in respect of machinery or plant being new, which has been installed after the 31st day of March, 1954, and which is wholly used for the purposes of the business carried on by the assessee, a sum by way of development rebate in respect of the year of installation equivalent to twenty five per cent of the actual cost of such machinery or plant to the assessee; Provided that no allowance under this clause shall be made unless the particulars prescribed for the purpose of clause (vi) have been furnished by the assessee in respect of such machinery or plant; Section 12 was to the following effect 12.