The recorder shall serve ex officio as clerk of the council, attend all its meetings unless excused therefrom by the council, keep an accurate record of its proceedings in a book provided for that purpose and sign all orders on the city treasurer. In his absence from a council meeting the mayor shall appoint a clerk of the council pro tem, who, while acting in that capacity, shall have the authority and duties of the recorder. The recorder shall countersign all instruments and writings authorized by this charter, the state constitution or laws, or council.