There are excepted from examination the following: (1) The confidential
clerk or secretary of any head of a Department or office; (2) cashiers
of collectors; (3) cashiers of postmasters; (4) superintendents of
money-order divisions in post-offices; (5) the direct custodians of
money for whose fidelity another officer is under official bond, but
these exceptions shall not extend to any official below the grade of
assistant cashier or teller; (6) persons employed exclusively in the
secret service of the Government, or as translators or interpreters or
stenographers; (7) persons whose employment is exclusively professional;
(8) chief clerks, superintendents, and chiefs of divisions or bureaus.
But no person so excepted shall be either transferred, appointed, or
promoted, unless to some excepted place, without an examination under
the Commission. Promotions may be made without examinations in offices
where examinations for promotion are not now held until rules on the
subject shall be promulgated.