STUDIES IN NATURE 



rain. Water, especially when it is in the form 

 of rain, has the power of dissolving certain 

 substances in the rocks and soil, and carries 

 them away invisibly with it down the streams. 

 In the same way we lose sight of a piece of 

 sugar if we leave it to melt in a cup of tea, yet 

 know it is there from the taste. Indeed, we 

 could find it again if we were to boil away all 

 the water, although it would be mixed with 

 other substances out of the tea and milk. By 

 thus dissolving some parts of the rock, the 

 water will break them up, or, at all events, 

 will cut little channels in them. In these 

 channels, or in other cracks, the water lodges ; 

 in winter this water freezes and, as we shall see 

 later on, expands, splitting open the cracks still 

 further with very great force. Thus the rocks 

 crumble away, and their particles are carried off, 

 visibly or invisibly, by rain-storms and floods. 



Let us look carefully at any stream or 

 moving water that we can find. In many 

 places there are little pebbles and other pieces 

 of rock rubbing themselves down against each 

 other ; here and there are banks of fine sand 

 and mud which are hardly to be distinguished 

 from the soil of the fields. A short walk by 

 the river-side will soon teach us that the hills 

 and slopes whence the water comes, whether 

 they are near at hand where we can see and 

 climb up them, or so far off that they only 

 appear as a blue line on the horizon on clear 



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