The justices of the Supreme Court, shall be elected by the qualified electors of the State at the general election, and shall hold office for the term of six years from and including the first Monday of January next succeeding their election; provided, that there shall be elected, at the first election under this Constitution, three justices of the Supreme Court who shall hold office from and including the first Monday of December A.D., eighteen hundred and sixty four, and continue in office thereafter, two, four and six years respectively, from and including the first Monday of January next suceeding [succeeding] their election. They shall meet as soon as practicable after their election and qualification, and at their first meeting shall determine by lot, the term of office each shall fill, and the justice drawing the shortest term shall be Chief Justice, and after the expiration of his term, the one having the next shortest term shall be Chief Justice, after which the senior justice in commission shall be Chief Justice; and in case the commission of any two or more of said justices shall bear the same date, they shall determine by lot, who shall be Chief Justice.