The spring to which he alludes, is the Morrissania creek. The point at which the work was to commence is fifty feet above tide, and the City Hall was the old building in Wall-street. He also says :

"When I first interested myself on this subject, I was in hopes a place sufficiently high might have been found, from whence the waters of the Bronx could have been conducted to New York, in pipes of conduit, without any previous machinery but ;

I am now satisfied no such place exists, for although water in an open aqueduct will run with tolerable fluency, having only six inches fall in the mile, yet in a pipe, or conduit, it requires five feet fall to produce the same effect; and even this fall is insufficient

where the pipes of conduit are of considerable length and of small diameter ,for the friction that is occasioned by the sides of the pipe of conduit, is in a quadruple ratio with its length. Now as the ground in the city of New York, to which water ought to be conveyed to a principal reservoir, is about forty feet above high tide, which is ten feet only below the level of the river Bronx, where it may be diverted, I consider it a fall perfectly inadequate to any design of conveying the water in a line of pipes it then becomes ne- ;

cessary, that the water of the Bronx should be elevated by the means of some machinery."