On the petition of five or more duly registered electors of any election district, setting forth that the appointment of overseers is a reasonable precaution to secure the purity and fairness of any primary or election in said district, it shall be the duty of the court of common pleas of the proper county, all the law judges of the said court able to act at the time concurring, to appoint two judicious, sober and intelligent electors of the said district belonging to different political parties, overseers of election to supervise the proceedings of election officers thereof and to make report of the same as they may be required by such court. Said overseers shall be persons qualified to serve upon election boards, but shall not be required to comply with the provisions of section 414 of this act.¹ They shall be sworn or affirmed by the judge of election, to the faithful discharge of their duties, and each shall sign said oath in duplicate, and shall have the right to be present with the officers of such primary or election within the enclosed space during the entire time the same is held, the votes counted, and the returns made out and signed by the election officers; to keep a list of voters if they see proper; to challenge any person offering to vote and interrogate him and his witnesses under oath in regard to his right of suffrage at said primary or election, and to examine his papers produced. Overseers shall sign returns of elections as hereinafter required. Whenever the members of an election board shall differ in opinion, the overseers, if they shall be agreed thereon, shall decide the question of difference.