Section 15. If a delinquent city or town does not pay its proportion of such expenses and charges within sixty days after the date of said notice, with interest thereon at the rate of ten per cent a year from the time when the same is paid by the county, the commissioners may, after a hearing, issue a warrant against such city or town for the amount which it was ordered to pay, with interest and the further costs of such notice and warrant, which shall be collected and paid into the county treasury.