RAJAGOPALA AYYANGAR, J.

The petitioners in this batch of revision cases are licensed tanners carrying on business in several places in the North Arcot District. Under rule 16(2) of the Turnover and Assessment Rules, these petitioners were assessed to sales tax on the total volume of their purchases. The assessments in dispute relate to the year 1951-52. The Assessing Officer as well as the Commercial Tax Officer on appeal had included in the taxable turnover, the purchases effected from "unlicensed" dealers, that is from those carrying on business outside the State. The Appellate Tribunal on appeal by these petitioners eliminated the last mentioned item in view of the decision of this Court in Hajee Abdul Shukoor v. State of Madras The petitioners, having obtained all the benefits derivable by them by virtue of the decision of this Court rendered up to that date, sought to challenge before the Appellate Tribunal the validity of the entire assessments, mainly on the ground that the provision, under which the petitioners applied for and obtained licences to deal in untanned hides and skins, was itself invalid. This attitude was adopted to obtain advantage from the decision