(1) THE facts in this batch of appeals brought by the Revenue, briefly stated, are that under Notification No. 132 of 1977-CE dated 18/6/1977 yarn used by composite textile mills in the manufacture of cotton fabrics was wholly exempted. The said notification was, however, withdrawn on 15/7/1977. On the midnight of 14/15/7/1977 the respondents in the various appeals had used some quantity of cotton yarn as well as some cotton yarn contained in cotton fabrics in stock. The Revenue attempted to collect duties on both these types of yarn in terms of the proviso to the notification dated 15/7/1977. The rate of duty for fabrics under the proviso was in two parts - namely, cotton fabrics duty and yarn duty. The validity of the proviso was challenged on the ground that it gave retrospective effect to yarn duty earlier exempted under the notification of 18/6/19777. In that connection reliance was placed on two decisions of the High courts of Gujarat and Bombay reported in the cases of Aryodaya Spg. and Wvg. Co. Ltd. v. Union of India and Shreeram Mills Ltd. v. Union of India . The department had preferred appeals against the aforesaid two judgments of the High courts of Gujarat and