64 Wild Life in a Southern County. 
leans, hollow and aged, across the water. This tree 
is the outpost of a thousand others that line the banks 
of the stream for mile after mile yonder down in the 
valley. How quickly this little fountain grows into a 
streamlet and then to a considerable brook !—without 
apparently receiving the waters of any feeders. In 
the first half-mile it swells sufficiently, if bayed up 
properly, to drive a mill—as, indeed, many of the 
springs issuing from these coombes do just below the 
mouth. In little more than a mile, measuring by its 
windings, it becomes broad enough to require some 
effort to leap it, and then deepens into a fair-sized’ 
brook. 
The rapidity of the increase is accounted for by 
the fact that every field it passes whose surface 
inclines towards it is a watershed from which an un- 
seen but considerable drainage takes place. When no 
brook passes through the fields the water stands and 
soaks downwards. or evaporates slowly: directly a 
ditch is opened it fills, and the effect of a stream is 
not only to collect water till then unseen, but to 
preserve it from evaporation or disappearance into 
the subsoil. Probably, if it were possible to start an 
artificial stream in many places, after a while it would 
almost keep itself going at times, provided, of course, 
that the bottom was not porous. Below the mouth 
of the coombe the water has worn itself a channel 
quite six feet deep in the chalk—washing out the 
flints that now lie at the bottom. Hawthorn bushes 
