JAGADISAN J.

Messrs. Raju and Mannar, Salem, is a registered firm carrying on the business of transport, by plying lorries for hire. It owned a fleet of ten lorries. In the accounting year--year ended March 31, 1955, relevant to the assessment year 1955-56--some of these lorries were fitted with new engines capable of being run on diesel oil replacing the old petrol driven engines. In the assessment proceedings under the Indian Income-tax Act for the year of assessment 1955-56, the firm claimed "development rebate" under section 10(2)(vib) of the Act and extra depreciation on these engines newly fitted to the vehicles. The Income-tax Officer rejected the claim. On appeal by the assessee to the Appellate Assistant Commissioner the decision of the Income-tax Officer was affirmed. The Appellate authority held that "development rebate" was permissible only in respect of plant or machinery which was "installed" and that fitting of new diesel engines to old lorries did not amount to any installation of plant or machinery. The assessee preferred a further appeal before the Income-tax Appellate Tribunal, Madras. The assessee again failed and the Tribunal dismissed the appeal in