1. The assessee, Brij Bhushan Lal, was a contractor who used to undertake the construction of building works for the M. E. S. Department. For the assessment years 1950-51, 1951-52, 1952-53 and 1954-55 assessments were made under the Indian Income-tax Act, 1922 (hereinafter referred to as the "the Act"), on the basis of the net profits determined at 10 per cent., 12.5 per cent., 12.5 per cent. and 10 per cent., respectively, of the amounts received by the assessee from M. E. S. Department. Later on, it came to the knowledge of the Income-tax Officer that the cost of materials supplied by the military authorities to be used in the building works by the assessee had not been disclosed by him and, therefore, notices under section 34 of the Act were issued to him. The orders of reassessment were made by adding the amounts representing the cost of èmaterials supplied by the military authorities, which amounts were Rs. 23,234, Rs. 8,940, Rs. 26,636 and Rs. 46,424, respectively, for the four years mentioned above. The same percentages were applied to determine the net profits on these amounts and the amount of income-tax levied was accordingly enhanced. The assessee filed appeals b