66. Second appeal.- A second appeal shall lie to the Chief Commissioner from an order deciding an appeal under Clause (a) or Clause (b) of Sub-section (1) of Section 64 on any of the following grounds and no other, namely:- (i) The decision being contrary to law or to some usage having the force of law, (ii) The decision having failed to determine some material issue of law or usage having the force of law; (iii) A substantial error or defect in the procedure as laid down in this Act or prescribed thereunder, which may possibly have produced error or defect in the decision of the case upon the merits. | 
