134 FRAGMENTS OF SCIENCE. 
is surprising. This arises, in part, from the lack of reso- 
nance; 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. 
On Friday, November 1, 1872, just before reaching the 
village of Niagara Falls, I caught, from the railway train, 
^_my first glimpse of the smoke of the cataract. Immedi- 
ately after my arrival I went with a friend to the northern 
end of the AmericanJlall. It may be that my mood at the 
time toned clown the impression produced by the first 
aspect of this grand cascade; but I felt nothing like disap- 
pointment, knowing, from old experience, that time and 
close acquaintanceship, the gradual interweaving of mind 
and nature, must powerfully influence my final estimate of 
the scene. After dinner we crossed to Goat Island, and, 
turning to the right, reached the southern end of the 
American Fall. The river is here studded with small 
islands. Crossing a wooden bridge to Luna Island, and 
clasping a tree which grows near its edge, I looked long at 
the cataract, which here shoots down the precipice like an 
avalanche of foam. It grew in power and beauty. The chan- 
nel spanned by the wooden bridge was deep, and the river 
there doubled over the edge of the precipice, like the swell 
of a muscle, unbroken. The ledge here overhangs, the 
water being poured out far beyond the base of the precipice. 
A space, called the Cave of the Winds, is thus enclosed 
between the wall of rock and the falling water. 
Goat Island ends in a sheer dry precipice, which con- 
nects the American and Horseshoe Falls. Midway between 
both is a wooden hut, the residence of the guide to the 
Cave of the Winds, and from the hut a winding staircase, 
called Biddle's Stan-, descends to the base of the precipice. 
On the evening of my arrival I went down this stair, and 
wandered along the bottom of the cliff. One well-known 
factor in the formation and retreat of the cataract was 
immediately observed. A thick layer of limestone formed the 
upper portion of the cliff. This rested upon a bed of soft 
shale, which extended round the base of the cataract. The 
violent recoil of the water against this yielding substance 
crumbles it away, undermining the ledge above, which, 
unsupported, eventually breaks off, and produces the 
observed recession. 
