This is an action for mandamus brought against one of the district judges for the District of New Jersey. The allegation complains that the district judge unduly restricted the applicant in his interrogatories in a pending litigation and that he acted contrary to what one of his fellow judges had ordered on the same point. We think that this is not a proper case for mandamus. TCF Film Corp. v. Gourley, 3 Cir., 1957, 240 F.2d 711. This Court has said many times that mandamus is not to be taken as a substitute for appeal. E. g., Green v. Murphy, 3 Cir., 1958, 259 F.2d 591. The district judge was acting in a case which was before him and the action he took was within his authority. If he was wrong the error can be corrected on appeal. The petition will be denied.