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. "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 seven hundred acres of water to a height of ten feet would require about three hundred million cubic feet of water, and while this was rising the waste-weir 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-weir might have discharged perhaps ninety million cubic feet. We would then have a total of flood water of three hundred and ninety million 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 was precipitated in places farther up. These figures I hold tentatively, but I am much inclined to believe that there was a cloud burst." Of course, the Johnstown disaster, great as it was, was by no means the greatest flood in history, since Noah's Deluge. The greatest of modern floods was that which resulted from the overflow of the great Hoang-Ho, or Yellow River, in 1887. This river, which has earned the title of "China's Sorrow," has always been the cause of great anxiety to the Chinese Government and to the inhabitants of the country through which it flows. It is guarded with the utmost care at great expense, and annually vast sums are spent in repairs of its banks. In October, 1887, a number of serious breaches occurred in the river's banks about three hundred miles from the coast. As a result the river deserted its natural bed and spread over a thickly-populated plain, forcing for itself finally an entire new road to the sea. Four or five times in two thousand years the great river had changed its bed, and each time the change had entailed great loss of life and property.