of water flowing on such occasions. With such opportunities to become acquainted with the changes of the stream they could not fail to know the quantity of water flowing at periods of the highest freshets, and know- ing it, to adapt an overfall of sufficient capacity for its dis- charge. For this purpose it was thought ample provision was made ; yet at the time when the work was nearly completed such a flood occurred as could not have been anticipated from previous knowledge of the River; the water filling the entire passage at the overfall, flowed over the top of the embank- ment where it was not supposed it could ever reach. The lower slope of this embankment was covered with a wall not calculated to resist the action of the water and it gave way ; the water broke through the embankment and rushed along the valley with most disastrous consequences. The breach occurred at an early hour in the morning ; and many persons were suddenly aroused from their sleep to escape before the approaching waters. Dwelling-houses and mills were carried away and three lives were lost. Two of those who were drowned had taken refuge in the tops of trees, but these being swept away they were drowned ; while others who were not able to reach the main land, but had also taken refuge in trees, were saved. The change wrought by the flood, in the appearance of the country, was truly wonderful and the destruction was complete. Night had Hi Q Mi 99 closed over that valley where all was happiness and quiet, but day opened upon a scene of desolation. The fertile fields were torn up and covered with masses of stone and gravel, and the flood left marks of its fury far up on the hill sides. At the commencement of the rain which caused this flood, the ground was covered with snow to the depth of eighteen inches : the weather became warm and the powerful rain storm continued incessantly for forty-eight hours. Notwith- standing the immense volume discharged at the overfall of the dam, the water was rising, during the night previous to this disaster, at the rate of fourteen inches per hour over the Reservoir, covering an area of four hundred acres. It occurred on the 8th of January, 1841. In repairing the breach it was decided to build an exten- sion of solid hydraulic masonry in the place of the portion of embankment which was carried away. The gate house and wing wall, which is seen on the ridge of the dam, shows where the masonry of the original struc- ture connected with the embankment which extended across the river. The whole length of the overfall is 251 feet. Access to the house over the culvert, is gained by a foot bridge which is seen in the picture. The masonry of the original structure has a rock foundation, and the extension of the overfall which is seen on the left of the house extend- ing across to the embankment has an artificial foundation of concrete. The masonry of the dam is about 8 feet thick at the top and 65 feet at the base ; it is built in a vertical form on the upstream side, with occasional offsets, and the lower face 100 has a curved form such as to pass the water over without giving it a direct fall upon the apron at the foot ; this apron is formed of timber, stone, and concrete ; and extends some distance from the toe of the masonry, giving security at the point where the water has the greatest action. A secondary dam has been built at a distance of 300 feet from the ma- sonry in order to form a basin of water setting back over the apron at the toe of the main dam so as to break the force of the water falling upon it. This secondary dam is formed of round timber, brush wood, and gravel ; it may be seen in the picture directly under the bridge which extends across below the main structure. On the upstream side of the masonry of the dam, an em- bankment of earth is filled in, extending 275 feet from the masonry at the base, and extending from the masonry with a slope of 1 foot in 5 on the top. The whole work about the dam possesses great interest, and though it be distant from the city and somewhat difficult of access, will not fail to please those who may take time to visit it. Just above the place where the dam is constructed the River had a bold turn and flowed along at the foot of a steep and rugged bank. A road passed along