It shall be the duty of the sergeant at arms to enforce the attendance of absent members, when directed properly so to do; to arrest all members or other persons, when lawfully authorized so to do; to keep and preserve order during the sessions of the Legislature; to convey to the post office the mail matter sent by the respective members, and to receive from such office the mail matter for such members, and to deliver the same to them on each morning of the session; to obey and enforce the orders of the presiding officers of the Legislature; and to do and perform such other duties as may be enjoined on him by law and the Legislature. It shall also be the duty of the sergeant at arms to procure a banner of the State of Nebraska, as described in section 90-102, and to place the same on top of the State Capitol building, there to be kept during the time the Legislature shall be in session. The colors of the banner shall be fast colors and the cloth shall be of substantial material. The banner shall be so arranged on the staff or pole that it may be raised or lowered with ease.