BROOK'S TOOLS AND ITS WORK 235 



previous loads of clay and pebbles. I found that 

 when the water reached a stretch of level ground 

 it had laid down part of its heavy load. Deposits 

 of rough sand and finer clay were left upon the 

 weeds and low vines in the stream bed. The 

 grass was matted and held down by sticky yellow 

 mud. At this rate it cannot be many years till 

 that low bit of ground is filled by the soil washed 

 off the fields above and transported by the brook. 

 What will the farmer back on the hill say to such 

 wholesale robbery? If he is a philosopher, he 

 may conclude that probably a part of his land was 

 brought down and deposited in the first place by 

 some large river in just such a way. Or he may 

 set the brook to turning his cornsheller, thus forc- 

 ing payment for the stolen goods. 



The next time I saw the Geologist I plied him 

 with questions. 



"Down at Stony Brook," I said, "there is a 

 place where the water goes through a deep, narrow 

 channel between the banks of very hard looking 

 rock. I can see how the water might have ground 

 out the channel wider and deeper when once it 

 got into the rock, but how did it get started in 

 the first place? Why didn't it go round instead 

 of through?" 



"Well," replied the thoughtful scientist, "maybe 

 there was a crack in the rock and the water had 

 to go that way because it was the shortest way 

 down. * The shortest way down' is what the 

 stream is looking for. Obstacles may turn it aside 

 for a time, but eventually it finds its level. Per- 



