4.—(1) The Board shall provide and have a common seal, and such seal shall be authenticated by the signature of the chairman of the Board or some other member thereof authorised by the Board to act in that behalf and the signature of an officer of the Board duly authorised by the Board to act in that behalf.

(2) All courts of justice shall take judicial notice of the seal of the Board, and every document purporting to be an order or other instrument made by the Board and to be sealed with the seal of the Board authenticated in accordance with this section shall be received in evidence and be deemed to be such order or instrument without further proof unless the contrary is shown.