Provision shall be made by law for the registration of the names of the Electors within the counties of which they may be residents and for the ascertainment by proper proofs of the persons who shall be entitled to the right of suffrage, as hereby established, to preserve the purity of elections, and to regulate the manner of holding and making returns of the same; and the Legislature shall have power to prescribe by law any other or further rules or oaths, as may be deemed necessary, as a test of electoral qualification.