§ 18. Custody of poll books and tally lists. Each of the Boards of Judges shall safely keep one poll book and tally list, and the ballots cast at each election; and shall, within ten days after such election, cause the other poll book and tally list to be transmitted, by the hands of a sworn officer, to the clerk of the Board transacting County business in their respective Counties, or to which the County may be attached for municipal purposes.