as well as of the devices for supplying themselves with water in use among the earliest peoples nothing material to the information of the general reader is omitted.

The Memoir of the Croton Aqueduct is compiled from official reports and documents, as for the most part is the sketch of the numerous attempts which, from an

early day, were made by the citizens of New York, to insure a supply of pure and wholesome water.

In preparing the Preliminary Essay, it was necessary to look into many books, and their pages, when suited to the design in hand, have been freely availed of.

Frontinus is the great authority as to the Roman Aqueducts, and his treatise is

nearly embodied entire in these pages.

Professor Charles Anthon's Dictionary of Antiquities, Stuart's Dictionary of Architecture, Hydraulia, a work published in London, by C. Matthews, in 1834, descriptive of water works in Great Britain, and the exceedingly clever book on Hydraulics and Mechanics, published in our city last year, by THOMAS EWBANK, have furnished or indicated much of the material used in the Essay. To Ewbank's book particular obligation is acknowledged, alike for what is to be found in its pages, and for references they afford to other sources of information.

Many other miscellaneous works have been consulted which are occasionally indicated in the marginal notes.

PREFACE. yji

To Mr. David T. Valentine, the Assistant Clerk of the Board of Aldermen,

the writer is greatly indebted for the means of compiling the Memoir. His long and