176 FRAGMENTS OF SCIENCE. 



shows that serious changes have taken place since his 

 time. He describes it as 'a great and prodigious 

 cadence of water, to which the universe does not offer 

 a parallel.' The height of the fall, according to Hen- 

 nepin, was more than 600 feet. ' The waters/ he says, 

 ' which fall from this great precipice do foam and boil 

 in the most astonishing manner, making a noise more 

 terrible than that of thunder. When the wind blows 

 to the south its frightful roaring may be heard for 

 more than fifteen leagues.' The Baron la Hontan, who 

 visited Niagara in 1687, makes the height 800 feet. 

 In 1721 Charlevois, in a letter to Madame de Mainte- 

 non, after referring to the exaggerations of his prede- 

 cessors, thus states the result of his own observations: 

 ' For my part, after examining it on all sides, I am 

 inclined to think that we cannot allow it less than 140 

 or 150 feet,' a remarkably close estimate. At that 

 time, viz. a hundred and fifty years ago, it had the 

 shape of a horseshoe, and reasons will subsequently be 

 given for holding that this has been always the form of 

 the cataract, from its origin to its present site. 



As regards the noise of the fall, Charlevois declares 

 the accounts of his predecessors, which, I may say, are 

 repeated to the present hour, to be altogether extrava- 

 gant. He is perfectly right. The thunders of Niagara 

 are formidable enough to those who really seek them 

 at the base of the Horeshoe Fall; but on the banks of 

 the river, and particularly above the fall, its silence, 

 rather than its noise, is surprising. This arises, in 

 part, from the lack of resonance; the surrounding 

 country being flat, and therefore furnishing no echoing 

 surfaces to reinforce the shock of the water. The 

 resonance from the surrounding rocks causes the Swiss 

 Reuss at the Devil's Bridge, when full, to thunder 

 more loudly than the Niagara. 



