A very serious loss, the first that deserves the name, occurred to the work on the night of the 7th January, 1841, by a great and sudden rise in the water of the Croton, and consequently of the Croton Lake, which carried away the dam for a distance of near 200 feet. It was the part described as an earthen embankment, with a base of 250 feet, and protected on the lower side by a dry stone wall of 20 feet thickness at the base. The mason work was but slightly injured. The storm and its effects are thus described by the Commissioners :

" This unprecedented rain storm commenced on Tuesday evening, the 5th instant, and continued without cessation until Thursday night, the 7th instant, at 12 o'clock. The commencement of the rain storm found the ground covered with snow eighteen

CROTON AQ.UEDUCT. inches deep. The rain was heavy and the temperature of the weather very warm. On the evening previous to the disaster, it was perceived that the water was rising on the bank above the overfall of the dam, very fast. The rise continued through the night to be equal to about 14 inches per hour. At half past 4 o'clock, the water having risen 15 feet above the overfall or apron of the dam, and two or three above the earthen embankment, (which was 12 feet above the overfall,) the embankment part of the dam gave way. It was obvious from the beginning, that if the water passed over the earthen embankment, it would carry away this part of the dam and the result to be expected imme- ;