Whenever, by reason of the absence, incapacity, or inability of the head or chief of any of the departments of the State Government to perform the duties of his office, or whenever a vacancy in the office of the head or chief of any of the departments of the State Government occurs, the duties of the head or chief of such department shall be performed by the deputy, chief clerk, or other person next in authority, until such disability is removed or the vacancy filled.
71 P.S. § 762