proposed by their report of November, 1833, the Commissioners en- gaged David B. Douglas, Esq., to re-examine his surveys, levels and calculations, and to ascertain whether lines for an aqueduct may not be designated that will require less labor and expense than those recommended by the report of 1833 ; whether a more economi- cal method of constructing the aqueduct may not be adopted ; whether the cost of build- ing culverts and bridges, making excavations and embankments, erecting the reservoirs, estimating the damages to water rights, &c., may not be reduced ; whether the expense of equalizing reservoirs may not be dispensed with ; and finally, whether the waters of the Croton may not be introduced from some different head, or by some other method, and at a much less cost, than that estimated in the report of 1833. On the 31st of December, 1833, something more than a month after we had pre- sented our report to the Common Council, Mr. D. S. Rhodes addressed a communication to the Board of Aldermen, proposing, for one million seven hundred thousand dollars, to introduce, through iron pipes, from the mouth of the Croton river, six million gallons of water every twenty-four hours ; and for two million seven hundred thousand dollars, to introduce sixteen million of gallons into the city of New York, at an elevation of 125 feet above low water, (see Corporation Document, No.54 ;) he presented another commu- nication on the 6th of January, 1834, objecting to the plan proposed by our engineer in 1833, for conducting the waters of the Croton to the city, stating, " that the most serious objection he has to urge against the plan is, that the water, however pure it may be at the fountain head, must inevitably become contaminated with some deleterious substance passing over such a variety of soils, and amalgamating so many mineral substances." He then proposes constructing a dam near the Quaker Bridge, on the Croton river, 45 feet high, which will give an elevation or head of 125 feet above tide of the Hudson ; " from this dam the pipes will rise gradually until they pass Sing Sing," and from thence descend to the shores of the Hudson, which, (as he states) " forms almost a straight line to the city, and very few obstacles to overcome ; the Harlem river will be crossed at very little expense." (See Document, No. 57.) On the 20th of January, 1834, Mr. Rhodes addressed a letter to the Chairman of the Commissioners, in which he says, " The natural abutments and high hills 32 MEMOIR OF THE near the Quaker Bridge, will give an elevation of 200 feet above the tide, if required. The canal to Sleepy Hollow will be on a level with the dam, which gives us the same head at Sleepy Hollow as we have at the dam. By my plan we arrive at Sleepy Hollow, travelling only eight miles with the whole of the Croton." On the 18th of April, 1834, Mr. Rhodes addressed a communication to the Com- mittee of the Common Council, on " Fire and Water," in which he proposes to build a dam at a point about four miles above the Quaker Bridge, of 32 feet high. From this he is to take the water in a canal 10 feet at bottom, 34 feet at top, and 8 feet in depth, on the same line nearly as that proposed for the Hudson river route, in our report of Novem- ber, 1833, to a reservoir near Harlem river, and from said reservoir to cross Harlem river by iron pipes, to the receiving and distributing reservoir on the island of New York ; the Corporation to pay all damages for water and land rights, and $1,700,000 in cash, when the work is finished according to contract ; but to allow him interest as the work pro- gresses. (See Document, No. 109.) It will not be expected, as we presume, either by Mr. Rhodes or by the Common Council, that the Commissioners should place much reliance upon the plans and proposi- tions of a gentleman, .who appears to have given the subject but a very superficial consi- deration at most. How he is to convey either six or sixteen millions of gallons of water from the mouth of the Croton, in accordance with his first proposition, and at an elevation of 125 feet above low water, at the city of New York, it would puzzle the most expert proficient in hydraulics to tell. By his communication of the 6th of January, 1834, he proposes raising a dam of 45 feet in height, near the Quaker Bridge, which is two or three miles above the mouth of the Cro'ton, from whence the water was