G.D.Khosla, J.

1. In these 49 petitions the vires of Punjab Act No. 7 of 1958 has been challenged before us. This Act amended the East Punjab General Sales Tax Act, 1948 and the amendment had the effect of imposing either new or additional liability in the form of sales or purchase tax upon the petitioners in respect of the goods in which they deal. Most of the petitioners are firms dealing in raw cotton. They purchase raw cotton, gin it in their factories and then sell ginned cotton and the cotton seed obtained in the process of ginning. Of the remaining petitions, the petitioners in Civil Writ No. 898 of I959 deal in non-ferrous metals, the petitioners in Civil Writs Nos. 822 to 827 of 1959 deal in oil-seeds and the petitioners in Civil Writ No. 1271 of 1959 deal in iron scrap. The petitioners in Civil Writ No. 861 of 1959 deal in hosiery goods. The point arising with a small variation is, however, identical in all the 49 petitions and it will be convenient to deal with all of them together.

2. Before the passsing of the amending Act the position was that certain types of goods were exempt from sales tax imposed by the East Punjab General Sales Tax Act, 1948. The Schedule