The said Commissioners shall have power to employ engineers, surveyors, and such other persons as, in their opinion, may be necessary to enable them to perform their duties under this act.

4 The said Commissioners shall adopt such plan as, in their opinion, may be most advantageous for procuring such supply of water and shall ascertain, as nearly as may ;

be, what amount of money may be necessary to carry the same into effect and for such :

purpose, they shall have power to make conditional contracts, subject to the ratification of the Common Council of the city of New York, with the owner or owners of all lands, tenements, hereditaments, rights or privileges whatsoever, which may be required according to such plan, for the purchase thereof, at stated prices which contracts shall be so ;

drawn as to be binding upon the said owners, respectively, in case the same shall be ratified by the said Common Council within two years from the passage of this act.

5. The said Commissioners shall make a report of their proceedings, under the foregoing sections of this act, containing a full statement and description of the plan adopted by them an estimate of the expense thereof, together with an estimate of the ;

probable amount of revenue to accrue to the city, upon the completion of the work with ;

the reasons and calculations upon which their opinions and the said estimates may be founded and all such other information, connected with the object of their appointment, :