the Appearance of Man on the Earth, Hi 



for miles, and extensive tracts of Alpine country, where nu- 

 merous flocks of cattle and goats are seen to pasture, became 

 the result of those subterraneous actions by which nature has 

 uplifted mountains. Fertility was gradually spread from the 

 Alps to the most distant countries of Europe. The heat en- 

 gendered in the narrow and deeply indented valleys of the 

 Alps would become intolerable, and forbid the growth of plants, 

 unless the atmosphere were constantly cooled down by the 

 neighbouring snow and ice-mountains as also by the ice-cold 

 waters of the glaciers. 



In the same way as the superfluous heat of former ages has 

 been, as it were, preserved by the coal-beds, the water which, 

 during winter, falls down in the form of snow, is stored up in 

 the Alps for the summer season. Glaciers descend from the 

 highest parts of the Alps, which lie buried in everlasting 

 snow, into those regions where the snow begins to melt in 

 summer. At the same time that those rivers, which do not rise 

 from the Alps or glaciers, as, for instance, our Elbe, Oder, &c., 

 are nearly dried up during the summer months, the streams 

 issuing from the Alps, as, for instance, the Rhine, the Danube, 

 the Rhone, the Etch, &c., continue to swell in proportion as 

 the heat increases ; for the greater the heat the larger will 

 be the supply of water, formed by the melting of the snow 

 and of the ice of the glaciers. Nature has covered the Alps 

 with eternal snow and ice ; but she avoided to do so with re- 

 gard to the inferior regions of lakes and of the sea, because 

 she intended them for the abode of organized beings. To 

 what expedient did Nature resort, in order to eflect her object ? 

 She fell upon a very simple plan, but which appears, on that 

 account, so much the more wonderful. 



All substances, both in the liquid and in the solid state, 

 contract during the process of cooling ; and the more so the 

 longer that process is carried on. We may observe this every 

 day on the liquid mercury contained in the glass tube of our 

 thermometers. We perceive that the column contracts when- 

 ever the cold increases. The thermometer is then said to fall. 

 The contraction of water is, however, regulated by a law very 

 different, and very peculiar. It is certainly true that water 



