New York City, Manhattan and the Bronx water supply / committee of 20, plan no. 2.1905Lithograph showing present mains 10" in diameter or larger, Mains 12" or larger proposed or under construction by water dept. Arteries proposed by National Board for immediate installation. Serial Nos. indicate location of hydrant tests. Colored to show areas of static pressures at hydrants as observed by National Board Engineers between 9 A.M. and 5 P.M.cartographic