172 HUTTONIAN THEORY 



along every pathway of inquiry. Facts that had long 

 been familiar came to possess a wider and deeper 

 meaning when their connection with each other was 

 recognised as parts of one great harmonious system 

 of continuous change. In no department of Nature, 

 for example, was this broader vision more remarkably 

 displayed than in that wherein the circulation of water 

 between land and sea plays the most conspicuous part. 

 From the earliest times men had watched the coming 

 of clouds, the fall of rain, the flow of rivers, and 

 had recognised that on this nicely adjusted machinery 

 the beauty and fertility of the land depend. But 

 they now learnt that this beauty and fertility involve 

 a continual decay of the terrestrial surface ; that the 

 soil is a measure of this decay, and would cease to 

 afford us maintenance were it not continually removed 

 and renewed ; that through the ceaseless transport of 

 soil by rivers to the sea the face of the land is slowly 

 lowered in level and carved into mountain and valley, 

 and that the materials thus borne outwards to the 

 floor of the ocean are not lost, but accumulate there 

 to form rocks, which in the end will be upraised into 

 new lands. Decay and renovation, in well-balanced 

 proportions, were thus shown to be the system on 

 which the existence of the earth as a habitable globe 

 had been established. It was impossible to conceive 

 that the economy of the planet could be maintained 

 on any other basis. Without the circulation of water 

 the life of plants and animals would be impossible, 

 and with that circulation the decay of the surface of the 

 land and the renovation of its disintegrated materials 

 are necessarily involved. 



