2.  An applicant may take the copyist or the clerk examination and any or all of the supplementary and special examinations provided for the departmental service, subject to such limitations as the Commission may by regulation prescribe; but no person whose name is on a departmental register of eligibles shall during the period of his eligibility be allowed reexamination unless he shall satisfy the Commission that at the time of his examination he was unable, because of illness or other good cause, to do himself justice in said examination; and the rating upon such reexamination shall cancel and be a substitute for the rating of such person upon the previous examination.

  3.  Exceptions from examination in the classified departmental service
  are hereby made as follows: 

(a) One private secretary or one confidential clerk of the head of each classified Department and of each assistant secretary thereof, and also of each head of bureau appointed by the President by and with the advice and consent of the Senate.

  (b) Direct custodians of money for whose fidelity another officer
  is under official bond; but this exception shall not include any officer
  below the grade of assistant cashier or assistant teller.

  (c) Disbursing officers who give bonds.

  (d) Persons employed exclusively in the secret service of the
  Government.

  (e) Chief clerks.

  (f) Chiefs of divisions.

4.  No person appointed to a place under the exceptions to examination hereby made shall within one year after appointment be transferred from such place to a place not also excepted from examination, but after service of not less than one year in an examination-excepted place he may be transferred in the bureau 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.

  DEPARTMENTAL RULE III.

In compliance with the provisions of section 3 of the civil-service act the Commission shall provide examinations for the classified departmental service at least twice in each year in every State or Territory in which there are a sufficient number of applicants for such examinations; and the places and times of examinations shall, when practicable, be so fixed that each applicant may know at the time of making his application when and where he may be examined; but applicants may be notified to appear at any place at which the Commission may order an examination.

  DEPARTMENTAL RULE IV.

  1.  Any person not under 20 years of age may make application for
  admission to the classified departmental service, blank forms for which
  purpose shall be furnished by the Commission.