§ 98. Duties of city engineer. It shall be the duty of the city engineer to perform all the ordinary engineering and surveying services in the affairs and business of the city and to supervise, under the general direction of the commissioner of public works, all the work done for the city in which the skill of his profession may be required or useful. He shall, under the direction of the commissioner of public works and the ordinances of the common council, act as the superintendent of public buildings, bridges, docks and wharves. He shall perform such other duties as may be prescribed by the commissioner of public works or by ordinance of the common council. He shall devote his time exclusively to the service of the city.