The said money shall be assessed and collected in the same manner as now provided by law for the assessment and collection of taxes in the city of New York. 8. It shall be the duty of the Water Commissioners of the city of New York, to finish and complete the aqueduct for supplying the said city with water, down to and including the distributing reservoir at Murray's hill, according to the plan adopted by the said Commissioners, and ratified by the Common Council of the said city, with such im-

190 MEMOIR OF THE material alterations as may be necessary, and as may be agreed upon by the said Water Commissioners and the said Common Council. 9. The said Commisoioners, by and with the consent of the said Common Council, shall have full power and authority to change the plan of crossing the Harlem river with arches and piers, and instead thereof to carry the water across the said river by means of inverted syphons of iron pipes, until otherwise directed by the Legislature, so as not unnecessarily to interrupt the navigation of the said river. And the said Commissioners are further authorised by and with the consent of the said Common Council, to alter the plan of constructing the reservoir at or near to Yorkville, and to complete so much of such reservoir as shall be deemed sufficient for the present purposes of such aqueduct.

10. It shall be the duty of the Mayor, Aldermen and Commonalty of the city of New York, to execute all the work necessary for supplying the said city with water, and for distributing the same for the use of the inhabitants thereof, below the said distributing reservoir at Murray's hill and the said Mayor, Aldermen, and Commonalty shall as- ;