VENKATARAMA AYYAR, J.

This petition raises substantial questions as to the interpretation of Article 286 of the Constitution. The petitioners are merchants carrying on business in the City of Madras as tanners and exporters of tanned hides and skins. This petition arises out of proceedings taken by the State of Madras under the Madras General Sales Tax Act for assessing the tax payable by the petitioners in respect of their dealings for the year 1950-51. The facts as stated before us by agreement of both the parties are that during this period the petitioners purchased 12, 123 pieces of hides and skins from Messrs. Abdul Gani & Company, Dacca, for a price of Rs. 1, 04, 595-4-6; 74, 000 pieces from merchants in Calcutta and Cawnpore for a price of Rs. 7, 18, 042-2-9; and 3, 694 pieces locally for a price of Rs. 43, 575-0-10, in all 89, 817 pieces for a price of Rs. 8, 66, 212-8-1. During the same period the petitioners themselves directly exported to foreign countries 7, 250 pieces on C.I.F. contracts for a price of Rs. 1, 67, 515-15-1; sold to dealers in Madras 60, 627 1/2 pieces for a price of Rs. 8, 55, 396-1-0; and sold locally 22, 807 pieces for a price of Rs. 2, 76,