The road superintendent shall have the power to purchase nails, lumber, tools, and other things necessary, where the need for the same is immediate and the value of said purchase does not exceed Fifty Dollars ($50.00). In cases of emergency he shall have power to contract for the immediate repair of a bridge, causeway, culvert, or a bad place in the road, provided such contract is not for a sum greater than Fifty Dollars ($50.00) and the need of the repair immediate and urgent. Such purchases and contracts shall be subject to ratification by the road commissioners and the board of supervisors.