2.  Any person not under 21 years of age may be examined for anyplace in the customs service to test fitness for which an examination is prescribed, and any person not under 20 years of age may be examined for clerk or messenger.

3.  A person desiring examination for admission to the classified customs service must make request, in his own handwriting, for a blank form of application, which request and also his application shall be addressed as directed by the Commission.

  4.  The date of reception and also of approval by the board of each of
  such applications shall be noted on the application paper.

  5.  Exceptions from examination in the classified customs service are
  hereby made as follows: 

  (a) Deputy collectors, who do not also act as inspectors,
  examiners, or clerks.

  (b) Cashier of the collector.

  (c) Assistant cashier of the collector.

  (d) Auditor of the collector.

  (e) Chief acting disbursing officer.

  (g) Deputy naval officers.

  (g) Deputy surveyors.

  (h) One private secretary or one confidential clerk of each
  nominating officer.

6.  No person appointed to a place under any exception to examination hereby made shall within one year after appointment be transferred from such place to another place not also excepted from examination, but a person who has served not less than one year in an examination-excepted place may be transferred in the customs office in which he is serving to a place not excepted from examination:  Provided, That before any such transfer may be made the Commission must certify that the person whom it is proposed to so transfer has passed an examination to test fitness for the place proposed to be filled by such transfer.

  CUSTOMS RULE III.

1.  The papers of every examination shall be marked under direction of the Commission, and each competitor shall be graded on a scale of 100, according to the general average determined by the marks made by the examiners on his papers.

  2.  The Commission shall appoint in each classified customs district a
  board of examiners, which shall—­

  (a) Conduct all examinations held to test fitness for admission
  to or promotion in the classified service of the customs district in
  which the board is located.

  (b) Mark the papers of such examinations, unless otherwise
  directed, as provided for by General Rule III, clause 12.

  (c) Conduct such examinations for the classified departmental
  service as the Commission may direct.

  3.  The papers of an examination having been marked, the board of
  examiners shall ascertain