The county controller may designate, in addition to the chief clerk, any clerk in his office to countersign warrants when properly drawn on the county treasurer, whenever, in the opinion of any such controller, it is necessary so to do for the public convenience. Warrants so countersigned by such clerk shall be honored by the county treasurer, with the same force and effect as if countersigned by the county controller or his chief clerk, during the period designated in writing to such county treasurer by the said county controller.
16 P.S. § 4954