RAMACHANDRA IYER, J.

This petition is filed under Article 226 of the Constitution for the issue of a writ of certiorari or other appropriate writ, calling for the records and quashing the order, dated 23rd November, 1956, in A-4-3774-55/56, on the file of the Deputy Commercial Tax Officer, Gudiyatham.

The petitioner-firm is a licensed dealer in hides and skins. In the course of its business, raw skins from places within and outside the State are purchased, tanned and the tanned skins exported to foreign countries. For the year 1955-56, the 2nd respondent, the Deputy Commercial Tax Officer, Gudiyatham, made an assessment on the petitioner on the basis of the re-enacted rule 16 of the Turnover and Assessment Rules, under the Madras General Sales Tax Act of 1939, on a turnover of Rs. 8, 23, 513-14-0. The legality of the assessment is challenged in this petition by impugning the constitutional validity of rule 16 of the Turnover and Assessment Rules.

Section 3(1) of the Madras General Sales Tax Act makes it obligatory on every dealer to pay a tax for each year on the total turnover (which is to be determined in accordance with rules prescribed in that behalf) at the rate specified in the section. The term "turnover" as defined in the Act is the aggregate amount, for which goods are bought or sold. Section 3(1) would, if unrestricted, enable a levy of sales tax on as many occasions as there are sales by dealers of particular goods, resulting in what is called a multi-point levy. Section 3(3) exempts a dealer whose turnover is less than Rs. 10, 000 in any year from payment of sales tax for that year. There are also exemptions and reductions in respect of the taxes leviable on certain goods. Section 5 enumerates them. In two cases there is a total exemption, and in four others a multi-point levy was avoided by prescribing a single point in the series of sale transactions which the goods may undergo within the State. Section 5(vi) relates to the levy of tax on the sale of hides and skins, modifying the otherwise multi-point liability into a single point one, the point in the series of sales being left to be prescribed by the rules. Section 19 confers powers on the State Government to make rules prescribing the determination of the turnover and fixation of the point of levy in regard to cases of single point levy. Accordingly the State Government framed the Turnover and Assessment Rules of 1939, which came into force on 1st October, 1939. Those rules have been amended, repealed and re-enacted from time to time,Rule 16 of the Turnover and Assessment Rules framed in 1939 provided for the levy of taxes on tanned and untanned skins by licensed and unlicensed dealers. Since then in three decisions of this Court certain defects in rule 16 were brought to light. Rule 16(5) which did not give the benefit of single point levy to unlicensed dealers, was declared invalid as contrary to section 5(vi), the assessable turnover was held not to include purchases from unlicensed dealers, and the transactions by unlicensed dealers were held not taxable as no point of levy was fixed. The result was that under the rules the unlicensed dealer escaped taxation while the licensed dealer had to pay it. The rules had therefore to be revised. Some months before the issue of the new rules, it was made obligatory on all dealers in hides and skins to take out licences. The new rule 16, which took the place of the old, was made by G.O. (P) No. 2733, Revenue, dated 3rd September, 1955. That runs :-

"16. (1) In the case of raw hides and/or skins the tax under section 5-A(iv) shall be levied from the dealer who is the last purchase in the State not exempt from taxation under section 3(3) on the amount for which they are bought by him.

(2)(i) In the case of hides or skins which have been dressed outside the State the tax under section 5-A(iv) shall be levied from the dealer who in the State is the first dealer in such hides or skins not exempt from taxation unde