[Powers and duties of president of board of regents;

president pro tem.] The president of said board shall be the chief executive officer, shall preside at all meetings thereof, except that when he is absent the board may appoint a president pro tem, sign all instruments required to be executed by said board; he shall also direct the affairs generally of the said school of mines [New Mexico institute of mining and technology], shall nominate and, by and with the advice of said board of regents, appoint all professors, instructors, tutors and other employes [employees] necessary to the proper conduct of said school of mines [institute], and in like manner shall determine the amount of their respective salaries.