It is therefore easily seen that there was ample water to cover the Conemaugh Valley to the depth of from ten to twenty-five feet. Such a volume of water was never known to fall in that country in the same time. Colonel T.P. Roberts, a leading engineer, estimates that the lake drained twenty-five square miles, and gives some interesting data on the probable amount of water it contained. He says:--"The dam, as I understand, was from hill to hill about one thousand feet long and about eighty-five feet high at the highest point. The pond covered above seven hundred acres, at least for the present I will assume that to be the case. We are told also that there was a waste weir at one end seventy-five feet wide and ten feet below the comb or top of the dam. Now we are told that with this weir open and discharging freely to the utmost of its capacity, nevertheless the pond or lake rose ten inches per hour until finally it overflowed the top, and, as I understand, the dam broke by being eaten away at the top. Calculating the Amount of Water. "Thus we have the elements for very simple calculation as to the amount of water precipitated by the flood, provided these premises are accurate. To raise 700 acres of water to a height of ten feet would require about 300,000,000 cubic feet of water, and while this was rising the waste dam would discharge an enormous volume--it would be difficult to say just how much without a full knowledge of the shape of its side walls, approaches and outlets--but if the rise required ten hours the waste river might have discharged perhaps 90,000,000 cubic feet. We would then have a total of flood-water of 390,000,000 cubic feet. This would indicate a rainfall of about eight inches over the twenty-five square miles. As that much does not appear to have fallen at the hotel and dam it is more than likely that even more than eight inches were precipitated in the places further up. These figures I hold tentatively, but I am much inclined to believe that there was a cloud burst." Six thousand men were at work on the ruins to-day. They are paid two dollars a day, and have to earn it. The work seems to tell very little, however, for the mass of debris is simply enormous. The gangs have cleaned up the streets pretty thoroughly in the main part of the city, from which the brick blocks were swept like card houses before a breeze. The houses are pulled apart and burned in bonfires. Nowhere is anything found worth saving. It is not probable that the mass of debris at the bridge, by which the water is tainted, can be removed in less than thirty days with the greatest force possible to work on it. That particular job is under the control of the State Board of Health. Every day adds to its seriousness. The mass is being cleared by dynamite at the bridge where the current is strongest, and the open place slowly grows larger. Not infrequently a body is found after an explosion has loosened the wreckage.