Justices of the Peace shall be elected by the voters of their respective towns; and towns having less than one thousand inhabitants may elect any number of Justices of the Peace not exceeding five; towns having one thousand and less than two thousand inhabitants, may elect seven; towns having two thousand and less than three thousand inhabitants, may elect ten; towns having three thousand and less than five thousand inhabitants, may elect twelve; and towns having five thousand, or more, inhabitants, may elect fifteen Justices of the Peace. Justices of the Peace shall not exercise judicial powers, except that they may serve as magistrates when so commissioned by the Supreme Court.