In suits not open to appeal, Collector may grant a re-hearing upon the discovery of new evidence, &c.

    In suits in which the judgment of the Collector is final as provided in the last preceding Section, the Collector may, upon the application of either party, if preferred within thirty days from the date of the decision, order the re-hearing of a suit, upon the ground of the discovery of new evidence or matter material to the issue of the case which the applicant had no knowledge of, or could not produce at the time of trial.