Upon the failure to collect such special tax or any part thereof as provided for in this subchapter, it shall be the duty of the City Collector on or before the first day of August next after the same shall become due and payable to make report in writing of such special tax to the County Treasurer of all lots and parcels of land upon which such special tax is unpaid, with the names of the respective owners thereof, so far as the same are known to the City Clerk, and the amount due and unpaid an each tract, together with a copy of this subchapter, which report shall be accompanied by oath that it is a correct return of the lots and parcels of land on which special tax levied by authority of the city for the cost of the sidewalk in this subchapter specified remains due and unpaid, and that the amounts therein stated as due and unpaid have not been collected.
('68 Code, § 6.25)