If it appear that any Works which the Commissioners deem necessary for promoting the Health or Convenience of the Inhabitants of the District within the Limit of the special Act cannot lawfully be carried into effect by the Commissioners, under the Powers vested in them by this or the special Act, by reason either that the Monies authorized to be raised by them are insufficient for the Purpose, or that any Lands are required which the Commissioners are not by this or the special Act authorized to take or use, or for any other Reason, the Commissioners may, by special Order as herein defined, but not otherwise, cause Application to be made to Parliament for an Act to enable them to execute such Works, and may defray the Expences of such Application out of the Rates authorized to be levied by them under this and the special Act.