Within ten days from the date of filing such petition the city clerk shall examine and from the voters’ register ascertain whether or not said petition is signed by the requisite number of voters, and if necessary, the council shall allow him extra help for the purpose; and he shall attach to said petition his certificate, showing the result of said examination. If by the clerk’s certificate the petition is shown to be insufficient, it may be amended within ten days from the date of said certificate. The clerk shall, within ten days after such amendment, make like examination of the amended petition, and if his certificate shall show the same to be insufficient, it shall be returned to the person filing the same, without prejudice, however, to the filing of a new petition to the same effect. If the petition shall be deemed to be sufficient, the clerk shall submit the same to the council without delay. If the petition shall be found to be sufficient, the council shall order the question to be submitted to the voters of the city.