3. Duties of the Engineer. The Engineer shall make all necessary explanations as to the meaning and intentions of the specifications and shall give all orders and directions, either contemplated therein or thereby, or in every case in which a difficulty or unforeseen condition shall arise in the performance of the work. Should there be any discrepancies in or between, or should any misunderstanding arise as to the import of anything contained in the plans and specifications, the decision of the Engineer shall be final and binding. Any errors or omissions in plans and specifications may be corrected by the Engineer, when such corrections are necessary for the proper fulfillment of their intentions as construed by him. 4. Duties of the Contractor. The Contractor shall do all the work and furnish all the labor, materials, tools and appliances necessary or proper for performing and completing the work required by the contract, in the manner called for by the specifications, and within the contract time. He shall complete the entire work at the prices agreed upon and fixed therefor to the satisfaction of the Commission and its Chief Engineer and in accordance with the specifications, the drawings, and such detailed drawings as may be furnished from time to time, together with such extra work as may be required for the performance of which written orders may be given and received as hereinafter provided. The Contractor shall place sufficient lights on or near the work and keep them burning from twilight to sunrise; shall erect suitable railings, fences or other protections about all open trenches, and provide all watchmen on the work, by day or night, that may be necessary for the public safety. The Contractor shall, upon notice from the Engineer that he has not satisfactorily complied with the foregoing requirements, immediately take such methods and provide such means and labor to comply therewith as the Engineer may direct, but the Contractor shall not be relieved of this obligation under the contract by any such notice or directions given by the Engineer, or by neglect, failure, or refusal on the part of the Engineer to give such notice and directions. The Contractor shall furnish such stakes and the necessary labor for driving them as may be required by the Engineer. He shall maintain the stakes when set, with reasonable diligence, and stakes misplaced due to the carelessness of the Contractor or his workmen shall be reset under the direction of the Engineer, at the Contractor’s expense.