¹* * * The Directors of the said Association shall have authority to expend the money of the said Association for the purpose of purchasing and erecting warehouses, and of warehousing and bonding goods therein, and to make and fulfil contracts for the said purpose, and to appoint and remove such servants as may be necessary for the said purpose and generally to manage all the concerns of the said Association, subject to such rules as may be laid down in the Bye-laws of the said Association, and to keep the seal of the said Association, and to use the said seal in the affairs of the said Association, provided always, that the said seal shall never be affixed to any instrument except in the presence and by the consent of three Directors, who shall sign their names on every such instrument in token of their presence and consent.