272 THE BEAUTIES OF NATURE CHAP, 
are continually changing their beds. Their 
courses at first sight seem to follow no rule, 
but, as it is termed, from a celebrated river 
of Asia Minor, to “meander” along without 
aim or object, though in fact they follow 
very definite laws. | 
Finally, when the river at length reaches 
the sea, it In many cases spreads out in the 
form of a fan, forming a very flat cone or 
“delta,” as it is called, from the Greek capi- 
tal A, a name first applied to that of the 
Nile, and afterwards extended to other rivers. 
This is due to the same cause, and resembles, 
except in size, the comparatively minute 
cones of mountain streams. 
Fig. 35 represents the delta of the Po, and 
it will be observed that Adria, once a great 
port, and from which the Adriatic was named, 
is now more than 20 miles from the sea. 
Perhaps the most remarkable case is that of 
the Mississippi (Fig. 86), the mouths of which 
project into the sea like a hand, or like the 
petals of a flower. For miles the mud is too 
soft to support trees, but 1s covered by sedges 
(Miegea); the banks of mud gradually be- 
