The City Manager is hereby authorized to request depositories of city funds to honor an order for payment when the instrument bears a facsimile of the signatures of the proper officers, and to charge the same to the account designated thereon or upon which it is drawn, as effectively as though the manually written signatures were affixed thereto. The authority is granted only for the purpose of permitting the officers an economy of time and effort.
(`86 Code, § 2.50)