Attempt to determine the mean height of Continents. 331 



the Oiiral in the country of the Issidones, called the whole of 

 Europe to the north of the Altai Mountains, Asia. In the 

 neighbouring region of the Baltic plains, near the shores of 

 the Baltic Sea, there are partial elevated masses which deserve 

 particular attention. To the west of Dantzic, between that 

 town and Butow, at the point where the shore of the sea ad- 

 vances much to the north, there are many villages situated at a 

 height of 400 feet ; the Thurmberg, moreover, the measure- 

 ment of which has given rise to many hypsometrical contro- 

 versies, rises, according to the trigonometrical observations 

 of Major Baeyer, to 1024 feet, which is perhaps the greatest 

 elevation to be found between the Harz and Oural. It is sur- 

 prising that, according to the measurements made by M. 

 Struve of the culminating point of Livonia, the Munamaggi, 

 this mountain rises only 4 toises higher than the Thurmberg 

 of Pomerania ; while, on the other hand, according to Captain 

 Albrecht's chart, the greatest depth of the Baltic Sea, between 

 Gothland and Windau, is not more than 167 toises, a mea- 

 surement almost identical with that of the Thurmberg. 



The flat countries exclusively European, the normal height 

 of which cannot be estimated at more than 60 toises, occupy, 

 according to exact measurements, a surface nine times that 

 of France. The extraordinary extent of this low region is 

 the cause of the mean continental height of all Europe, over 

 an extent of 17,000 square geographical miles, being 30 toises 

 below the result we have found for France. As to the rest, 

 not to occupy more time with numbers, M. de Humboldt adds, 

 that an important consideration in the study of the general 

 phenomena of geology is, that the elevated masses, over ex- 

 tensive counti'ies, in the form of plateaux, produce an entirely 

 different effect on the elevation of the centre of gravity of 

 the volume from that of chains of mountains, when they have 

 the same importance in breadth and in height. While the 

 Pyrenees produce scarcely the effect of a single toise on the 

 whole of Europe, the system of the Alps, which cover a 

 surface almost quadruple that of the Pyrenees, has the effect 

 of 3i toises ; the Iberian peninsula, with its compact massive 

 plateau of 300 toises, produces the effect of 12 toises. The 

 plateau just named, therefore, has an effect on the whole of 



