Section 236. If a town or the city council of a city accepts this section or has accepted corresponding provisions of earlier laws, the mayor or selectmen may from time to time appoint, for a term not exceeding one year, and may at any time remove, weighers of hay, who shall be sworn to the faithful performance of their duty and who shall have the superintendence of the hay scales belonging to such city or town, and shall weigh hay offered for sale therein and any other article offered to be weighed. Cities and towns may establish ordinances and by-laws for the regulation of hay scales and of the compensation of weighers of hay. Whoever, not having been so appointed, sets up hay scales in a city or town for the purpose of weighing hay or other articles offered to be weighed shall forfeit to the use of such city or town twenty dollars a month, so long as such scales are maintained.