Section 57. They shall, at least twenty days before the annual or biennial city or town election, and except in Boston, at least sixty days before the biennial state election, cause copies of the voting lists provided for in the two preceding sections to be posted in their principal office and in one or more other public places in the city or town, and in each ward of a city and in each precinct of a town. Upon application made by any state political committee organized in accordance with law, the clerk of the board of registrars shall furnish to it a copy of the voting list free of charge.