( 1. ) THE Petitioner is an existing company, within the meaning of the Companies Act, 1956, having its registered office at Birlagram, Nagda, in this State. The Petitioner is engaged in the manufacture of staple fibre of which sulphuric acid is an essential ingriedient. It also manufactures sulphuric acid and uses or consumes the entire quantity in the manufacture of staple fibre without selling any part of it. The dispute in this petition relates to the excise duty payable on the sulphuric acid so manufactured by the petitioner and used or consumed in its entirety in the manufacture of staple fibre at Nagda during the period between 10-11-1976 and 31-10-1978.

( 2. ) PRIOR to 10-11-1976, excise duty on sulphuric acid was levied and collected on the basis of tariff value fixed by the Central Government from time to time under Section 3 of the Central Excises and Salt Act 1944 (hereinafter referred as the Act ). However, with effect from 10-11-1976, excise duty on sulphuric acid became payable with reference to its value determined under Section 4 of the Act, instead of on the tariff value prior to that date. The duty of excise payable on sulphuric acid is at the rate ad va