Whenever the board of supervisors of any county shall order the copying of any rolls or other papers, as provided in section 1 of this act, the treasurer of such county shall have the supervision of such work, and shall employ some proper person or persons to perform the same, who shall, before entering upon the discharge of such duty, subscribe an oath to perform the same, in a true and faithful manner; and it shall be the duty of such county treasurer to compare all rolls or papers so copied, with the originals, and shall attach to each separate copy, roll, or other paper, his certificate that the same is a true copy of the original roll, or other paper, and that such copy was made by a person duly authorized under the provisions of law to make the same.