Upon the filing of such petition or request in writing with the municipal clerk, he shall forthwith call an election, to be held on the fourth Tuesday following the date of the filing of the petition with him, but such special election shall not be held within four weeks of the municipal election. The clerk shall cause public notice of the time and place of holding such election to be given by advertisement signed by himself and posted in at least twenty conspicuous places distributed throughout the municipality, and published for at least two issues on different days previous to the time of such election in at least one newspaper which has been so published in such municipality for at least six months last past, and if there be no such newspaper then in a newspaper having a general circulation therein.