Judgement

GROVER, J.:- This is an appeal certificate from a judgment of the Assam and Nagaland High Court.

2. The appellant is a company incorporated under the Indian Companies Act, 1956 in the State of Assam. It started its business on November 17, 1962 for the first time. Its business includes sale and purchase of petroleum coke. Until September 1, 1964 no sales tax was levied or was payable by the company on the sale of petroleum coke because in Schedule 3 of the Assam Sales Tax Act, 1947, hereinafter called the Assam Act , which enumerated the goods on which tax was not payable, Entry 7 read "coal, coke and coalgas". By Amending Act 14 of 1964 the said Entry was deleted from Schedule 3 to the Assam Act with effect from September 1, 1964. By means of a letter dated July 7, 1964 the Superintendent of Taxes, Assam, informed the company that the petroleum, coke and gas were taxable at the rate of 5 Np in a rupee under the Assam Act and directed the company to submit the return for all the periods prior to September 1, 1964 and also apply for registration under the Assam Act for the sale of petroleum coke within the State of Assam. The company preferred a petition for revision under