Upon calculating this power, however, itwas found incapable of raising more than 5,000,000 gallons daily, and as this would leave a deficit, even for present purposes when the work should be finished, of two or three millions of gallons a day, it was thought unnecessary to pursue the examination of that route.

Another line commencing at Popham's Calico Factory, was carefully surveyed. By rebuilding and raising the dam, a head of 142 feet above tide would be obtained, and no serious obstacles occur in the route before intersecting those laid out for the Croton. But upon guaging the streams of supply, it was at once perceived that no reliance could be placed upon a sufficient quantity from them.

" On the 15th of " I August," says Maj. Douglas, guaged the outlet of the Rye ponds, and found it discharging 950,400 gallons per day. On the 20th, and again on the 5th September, it was discharging very nearly the same quantity but' between the last ;

two dates, a period of 15 days, it had fallen, having been drawn down by the proprietor two and six tenths inches. This draught, calculated upon the surface of the pond, 205 acres, gives a daily

CROTON AQ.UEDUCT.

decrease of 957,500 gallons in the volume of the pond ; showing that, during the time observed, the supplies of the pond, from whatever quarter they come, were in quantity about 7,000 gallons per day less than the evaporation.

By damming the valley, about three-fourths of a mile below the small pond, so as to back up the water to three feet above the ordinary level of the upper pond, a reservoir of 360 acres will be formed and by deepening the outlet of the upper pond, so as to ;