“ When an appointment or employment of an unskilled laborer is to be made, the appointing officer shall request the board to certify eligibles, stating the principal duties of the position. If in the opinion of the board the duties are of the grade performed by classified employees, the facts shall be referred to the Civil Service Commission to determine the status of the position as classified or unclassified under section 3 of civil service Rule XIII, and the vacancy shall be filled in accordance with such finding. ”

“ Appointment or employment for temporary service shall be made as far as practicable as appointments to permanent positions. Where the needs of the service require, the board may authorize the temporary appointment of any eligible or of a person whose name is not on any register; but no person shall render more than thirty days' temporary service in any period of twelve months where appointed out of his turn, or outside these regulations. ”

“ In the exercise of power conferred by section 1753 of the Revised Statutes, the President makes the following regulations to govern the selection of unskilled laborers for appointment or employment in the Executive civil service with a view of securing skill and efficiency and of excluding other considerations. ”