HO THE FAIRY-LAND OF SCIENCE. 
the top of a cliff to a depth of many feet till it comes to 
solid rock, and then lying spread over a wide space. 
Here it forms a kind of watery mud, which is a very 
unsafe foundation for the hill of earth above it, and so 
after a time the whole mass slips down and makes a 
fresh piece of land at the foot of the cliff. If you have 
ever been at the Isle of Wight you will have seen an 
undulating strip of ground, called the Undercliff, at 
Ventnor and other places, stretching all along the sea 
below the high cliffs. This land was once at the top 
of the cliff, and came down by a succession of land- 
slips such as we have been describing. 
You will easily see how in forming earth-pillars 
and causing landslips rain changes the face of the 
country^ but these are only rare effects of water. It is 
when the rain collects in brooks and forms rivers that 
it is most busy in sculpturing the land. Look out 
some day into the road or the garden where the ground 
slopes a little, and watch what happens during a 
shower of rain. First the rain-drops run together in 
every little hollow of the ground, then the water be- 
gins to flow along any ruts or channels it can find, 
lying here and there in pools, but always making its 
way gradually down the slope. Meanwhile from other 
parts of the ground little rills are coming, and these 
all meet in some larger ruts where the ground is low- 
est, making one great stream, which at last empties 
itself into the gutter or an area, or finds its way down 
some gratings into the sewer. 
Now just this, which we can watch whenever a 
heavy shower of rain comes down on the road, hap- 
