Judgment

KHANNA, J. :- This judgment would dispose of four civil appeals Nos. 471 to 474 of 1969 which have been filed on certificate granted by the Madras High Court and are directed against the common judgment of that court, whereby petitions under Article 226 of the Constitution of India filed by the appellants were dismissed. The crucial question which arises for determination in these appeals is whether the provisions of Madras General Sales Tax (Third Amendment) Act. 1967 (Act No. 19 of 1967) are invalid on the ground that they seek to impose sales tax with retrospective effect in an unreasonable manner.

2. According to entry 47 of First Schedule to the Madras General Sales Tax Act, 1959 (Madras Act 1 of 1959) (hereinafter referred to as the principal Act), the sale of "lubricating oils and greases" was liable to sales tax at the point of first sale in the State at 6 per cent. With effect from April 1, 1964 entry 47 was amended by Madras Act 7 of 1964 and instead of the words "lubricating oil and greases" in that entry the following words were substituted :

"Lubricating oils, all kinds of mineral oils (not otherwise provided for in this Act) quenching oils and greases."

Till Sept