The overfall was made of such length as was thought sufficient to pass all the water of the river during its highest stages, and with the view of adapting it to such purpose, examinations were made to find the highest marks of floods on the banks of the river and those who were engaged in determining these marks were guided also by the observations of the inhabitants of the vicinity who had long known the river in its various

stages. High freshets were witnessed during the construction of the work, for in the course of two years that the

work was going up, all the various changes and freshets of rainy seasons were experienced, and those in charge of it

did not neglect to note the quantity 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 knowing it, to adapt an overfall of sufficient capacity for its discharge. 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 embankment 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.