198 THE POPULAR SCIENCE MONTHLY. 



Having described the desolation sometimes produced in Switz- 

 erland by the bursting of glacial lakes, he remarks that to a still 

 greater extent the " period of conflict between the ice and the 

 river must have been a terrible time for the lower Ohio Valley 

 and its inhabitants. At times the river was dry, and at others 

 bank-full and overflowing. The frost of winter, by lessening the 

 supply, and the ice-tongue by forming a dam, combined to hold 

 back the water. The sun of summer, by melting the dam, and the 

 pressure of the accumulated water, by bursting it, combined to 

 let off all at once the whole of the retained store. Terrible floods 

 of water and ice, laden with stones, gravel, and sand, must have 

 poured down the river and have swept away everything in their 

 path trees, animals, and man, if present. 



" How many years or ages this conflict between the lake and 

 the dam continued it is quite impossible to say, but the quantity 

 of wreckage found in the valley of the lower Ohio, and even in 

 that of the Mississippi, below their point of junction, is sufficient 

 to convince us that it was no short time. ' The Age of Great 

 Floods ' formed a striking episode in the story of ' The Retreat 

 of the Ice.' Long afterward must the valley have borne the 

 marks of these disastrous torrents, far surpassing in intensity 

 anything now known on the earth. The great flood of 1884, when 

 the ice-laden water slowly rose seventy-one feet above low- water 

 mark, will long be remembered by Cincinnati and its inhabitants. 

 But that flood, terrible as it was, sinks into insignificance beside 

 the furious torrent caused by the sudden even though partial 

 breach of an ice dam hundreds of feet in height, and the discharge 

 of a body of water held behind it, and forming a lake of twenty 

 thousand square miles in extent. 



"To the human dwellers in the Ohio Valley for we have rea- 

 son to believe that the valley was in that day tenanted by man 

 these floods must have proved disastrous in the extreme. It is 

 scarcely likely that they were often forecast. The whole popula- 

 tion of the bottom lands must have been repeatedly swept away ; 

 and it is far from being unlikely that in these and other similar 

 catastrophes in different parts of the world, which characterized 

 certain stages in the Glacial era, will be found the far-off basis on 

 which rest those traditions of a flood that are found among all 

 savage nations, especially in the north temperate zone." 



Mr. W. H. Dines, an English meteorologist, is inclined to believe, from ob- 

 servations and experiments made with his new anemometer, that a gust sel- 

 dom maintains its full power for more than one or two seconds; and that the 

 extreme velocity occurs in lines which are roughly parallel to the direction 

 of the wind. 



