the Appearance of Man on the Earth. 60 



But it is not only on the surface that the Rhine assumes the 

 temperature of 32° Fah. ; it may be traced at whatever depth we 

 examine it. Several years ago this matter was very carefully 

 investigated at Strasburg. Water, drawn from different depths, 

 shewed the same temperature of 32° with that on the surface. 

 In some places the Rhine is more than fifty feet deep. 

 This river being frozen three days after the commencement of 

 severe frost, it follows that a lake 1500 feet deep, for instance 

 the Lake of Geneva, will cool down to 32° in the course of 

 three months ; so that the next moment it may be converted 

 into one solid mass of ice. Considering that in the Alps, 

 where the lakes occupy a much more elevated situation, the 

 winter makes its appearance in November, and frequently lasts 

 till April or May, it is evident that such lakes will already be 

 frozen to the bottom before the end of February. It is true, 

 that, in the succeeding summer, the ice would begin to melt 

 on the surface, but that would scarcely produce a sheet of 

 water a few feet deep ; for, in order to melt a mass of ice 1500 

 feet thick, it would require our summer heat to continue with- 

 out intermission for many years. Such lakes would cease to 

 deserve the appellation of lakes ; they would for ever present 

 one solid mass of ice. 



Such would have been the fate of the magnificent lakes in 

 Switzerland, in Upper Bavaria, and in Upper Italy ; of the 

 charming Lago Maggiore, of the Lago di Como, and others. 

 Their fish would have been frozen to death, and their shores 

 stripped of that matchless luxuriance of vegetation for which 

 they are so remarkable. Steam-boats would have been out of 

 the question, for the thin sheet of water obtained by the melt- 

 ing of the upper crust of ice would scarcely admit of the use of 

 flat canoes. 



Our beautiful lakes in Northern Germany, for instance 

 those of Brandenburg and Mecklenburg, and which are almost 

 the only ornaments of those countries, would be visited by a 

 similar misfortune. We might certainly, up to the middle of 

 summer, amuse ourselves with skating, and with excursions on 

 sledges ; but then the ice would melt so slowly as to leave the 

 lakes scarcely accessible to the smallest boats. 



How different would be the aspect of countries if water had 



