144 FRAGMENTS OF SCIENCE. 
sudden bend to the northeast, forming nearly a right 
angle with its previous direction. The water strikes the 
concave bank with great force, and scoops it incessantly 
away. A vast basin has been thus formed, in which the 
sweep of the river prolongs itself in gyratory currents. 
Bodies and trees which have come over the falls, are stated 
to circulate here for days without finding the outlet. From 
various points of the cliffs above, this is curiously hidden. 
The rush of the river into the whirlpool is obvious enough; 
and though you imagine the outlet must be visible, if one 
existed, you cannot find it. Turning, however, round the 
bend of the precipice to the northeast, the outlet comes 
into view. 
The Niagara season was_over; the chatter of sightseers 
had^ceaseHT" and the scene~~p resented itself as one of holy 
seclusion and beauty. I went down to the river's edge, 
wKere the weird loneliness seemed to increase. The basin 
is enclosed by high and almost precipitous banks covered, 
at the time, with russet woods. A kind of mystery attaches 
itself to gyrating water, due perhaps to the fact that we 
are to some extent ignorant of the direction of its force. 
It is said that at certain points of the whirlpool, pine trees 
are sucked down, to be ejected mysteriously elsewhere. 
The water is of the brightest emerald-green. The gorge 
through which it escapes is narrow, and the motion of the 
river swift though silent. The surface is steeply inclined, 
but it is perfectly unbroken. There are no lateral waves, 
no ripples with their breaking bubbles to raise a murmur; 
while the depth is here too great to allow the inequality of 
the bed to ruffle the surface. Nothing can be more beauti- 
ful than this sloping liquid mirror formed by the Niagara, 
in sliding from the whirlpool. 
The green color is, I think, correctly accounted for in 
the last Fragment. ,. While crossing the Atlantic in 1872-73 
I had frequent opportunities of testing the explanation 
there given. Looked properly down upon, there are 
portions of the ocean to which we should hardly ascribe a 
trace of blue; at the most, a mere hint of indigo reaches 
the eye. The water, indeed, is practically black, and this 
is an indication both of its depth and of its freedom from 
mechanically suspended matter. In small thicknesses 
water is sensibly transparent to all kinds of light; but, as 
the thickness increases, the rays of low refrangibility are 
