62 SCIENTIFIC ILLUSTRATIONS [Con 



spread their carpet of green over every sheltered nook from 

 which the snow has melted, and the rest of the scanty but 

 often hrightsome flora of remotest North puts on with marvellous 

 rapidity its summer aspects. Here is indeed a scene which, by 

 contrast, can be well appreciated. Spenser in his "Faerie 

 Queene " indicates others : 



" Sleepe after toyle, 

 Port after stonnie seas, 

 Ease after warre, 

 Death after life, 

 Doth greatly please." BE. 



Conventional Opinion. 



The clearest proofs abound that in numberless cases rivers 

 have simply availed themselves of the courses prepared for them 

 by previous breaks in the rocks, opening depressions along 

 which the waters have passed. Take one of the largest of our 

 European streams, the Danube, and trace it from its source in 

 the flat plauteaux of Central Germany in which it rises, and 

 you see that whilst it never can have been a torrential stream, 

 it simply maintains a steady slow-flowing current as it winds 

 through the steep defiles and high cliffs of the hardest gneiss 

 and granite which had been opened out to receive it ; for even 

 now, where the gorges are deepest and narrowest, and where 

 the river must therefore have exerted its greatest power, the 

 buildings of Roman times have been daily bathed by the 

 stream, and not a fragment of them has been worn away. 

 "When, indeed, we look to the lazy-flowing, mud-collecting 

 Avon, which at Bath passes along that line of valley, how 

 clearly do we see that it never deepened its channel 1. Still more 

 when we follow it to Bristol and observe it passing through the 

 steep gorge or hard mountain limestone at Clifton, every one 

 must then be convinced that it never could have produced such 

 an excavation. In fact, we know that from the earliest periods 

 of history is has only accumulated mud, and has never worn 

 away any portion of the rock. The clear inference then, in 

 these and countless other instances, is that rivers in all such N 

 cases simply flow in the gorges and depressions prepared for 



