During the absence of the Attorney General and the chief deputy from the seat of government, or when so directed by the Attorney General, the assistants to the Attorney General may render official opinions to such officers as the Attorney General is permitted to advise, and may perform such other duties as may be directed by the Attorney General. During such absence, such authority shall be vested in the senior assistant to be designated by the Attorney General, and in the absence of the latter also, in the next ranking assistant. The performance of such duties by such assistants shall have the same force and effect as if performed by the Attorney General.