Those allowances include those 96 allowed in respect of depreciation, as mentioned in clauses (vi) and (vi a) of sub section (2), the material part of which at the relevant time read as under: (vi) in respect of depreciation of such buildings, machinery plant or furniture being the property of the assessee, a sum equivalent . to such percentage on the written down value thereof as may in any case or class of cases be prescribed, and where the buildings have been newly erected or the machinery or plant being new, not being machinery or plant entitled to the development rebate under clause (vi b), has been installed, after the 31st day of March, 1945, and before the 1st day of April, 1956, a fur ther sum (which shall however not be deductible in determining the written down value for the purposes of this clause) in respect of the year of erection or installation equivalent, (a) in the case of buildings the erection of which is begun and completed between the st day of April 1946 and the 31st day of March 1956 (both dates inclusive), to fifteen per cent, of the cost thereof to the assessee; (b) in the case of other buildings, to ten per cent of the cost thereof to the assessee; (c) in the case of machinery or plant, to twenty per cent, of the cost thereof to the assessee; Provided that (a). . . . (b). . . . (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the aggregate of all allowances in respect of depreciation made under this clause and clause (vi a) or under any Act repealed hereby, or under the Indian Income tax Act, 1886 (II of 1886), shall, in no case, exceed the original cost to the assessee of the buildings, machinery, plant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 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," 97 It is apparent from the above provisions that depreciation of three distinct kinds could be allowed in respect of buildings, machinery and plant.