All regular applications for the competitive examinations for admission
to the classified service must be made on blanks in a form approved by
the Commission. All requests for such blanks and all applications for
examination must be addressed as follows: (1) If for the classified
departmental service, to the United States Civil Service Commission,
Washington, D.C.; (2) if for the classified postal service, to the
postmaster under whom service is sought; (3) if for the classified
customs service, to the head of either customs office in which service
is sought. All officers receiving such applications will indorse thereon
the date of the reception thereof and transmit the same to the proper
examining board of the district or office where service is sought or,
if in Washington, to the Civil Service Commission.