Science, Geology and Physics 



by the water; and all else in the regions of nature appears to be 1822 

 dumb. This noise is a vast thunder, filling the heavens; shaking Wlg ' 

 the earth; and leaving the mind, although perfectly conscious of 

 safety, and affected with a sense of grandeur only, lost and aston- 

 ished, swelling with emotions which engross all its faculties, and 

 mock the power of utterance. 



The strength of this sound may be illustrated in the following 

 manner: The roar of the ocean on the beach, South of Long- 

 Island, is sometimes heard in New-Haven, at the distance of 

 forty miles. The cataract of Niagara is heard ten miles farther. 



All cataracts produce greater or less quantities of mist; a 

 proof to the common eye, that vapor may rise by mere agitation. 

 The mist, raised here, is proportioned to the greatness of the cause. 

 A large, majestic cloud, visible from an advantageous position for 

 a great number of miles, rises without intermission from the whole 

 breadth of the river below; and, ascending with a slow, solemn 

 progress, partly spreads itself down the stream by an arching, and 

 wonderfully magnificent motion; and partly mounts towards 

 heaven, blown into every wild and fantastical form; when, sep- 

 arating into smaller clouds, it successively floats away through 

 the atmosphere. 



Nearest to the shore a considerable quantity of this vapor 

 impinges against the rock; and, continually accumulating, 

 descends in a constant shower of drops, and little streams. A 

 person, standing under the shelving part of these rocks, would in 

 a short time be wet to the skin. 



In the mist, produced by all cataracts, rainbows are ordinarily 

 seen in a proper position, when the sun shines; always, indeed, 

 unless when the vapour is too rare. Twice, while we were here, 

 the sun broke through the clouds, and lighted up in a moment the 

 most lucid rainbow, which I ever beheld. In each instance 

 the phenomenon continued a long time; and left us in perfect 

 leisure to enjoy its splendours. It commenced near the precipice, 

 and extended, so far as I was able to judge, at least a mile down 

 the river. In the latter instance, the sun was near the horizon; 



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