(15) For the establishment of a bureau of efficiency, consisting of the Commission, the Secretary thereof and the Auditor, for the purpose of determining the duties of each position in the classified service, fixing standards of efficiency, investigating the methods of operation of the various departments, and recommending to the Board of Supervisors and department heads measures for increasing individual, group and departmental efficiency, and providing for uniformity of competition and simplicity of operation. The Commission shall ascertain and record the comparative efficiency of employees in the classified service and shall have power, after hearing, to dismiss from the service those who fall below the standard of efficiency established. (16) For the adoption and amendment of rules only after public notice and hearing. The Commission shall adopt such other rules, not inconsistent with the foregoing provisions of this section, as may be necessary and proper for the enforcement of this Article. SEC. 35: In case of a vacancy in a position requiring peculiar and exceptional qualifications of a scientific, professional or expert character, upon satisfactory evidence that competition is impracticable and that the position can best be filled by the selection of some designated person of recognized attainments, the Commission may, after public hearing and by the affirmative vote of all three members of the Commission, suspend competition, but no such suspension shall be general in its application to such positions, and all such cases of suspension shall be reported, together with the reason therefor, in the annual reports of the Commission. SEC. 36: All examinations shall be impartial and shall deal with the duties and requirements of the position to be filled. When oral tests are used, a record of the examination, showing basis of rating, shall be made. Examinations shall be in charge of the chief examiner except when members of the commission act as examiners. The commission may call on other persons to draw up, conduct or mark examinations, and when such persons are connected with the county service it shall be deemed a part of their official duties to act as examiners without extra compensation.