I have found by
a laborious investigation,* which from its nature, can only give a maximum
limit, that the center of gravity of the volume of the land raised above the
present level of the sea in Europe and North America is respectively
situated at an elevation of 671 and 748 feet, while it is at 1132 and 1152
feet in Asia and South America.
[footnote] *'De la hauteur Moyenne des Continents', in my 'Asie Centrale',
t. i., p. 82-90, 165-189. The results which I have obtained are to be
regarded as the extreme value ('nombres-limites'). Laplace's estimate of
the mean height of continents at 3280 feet is at least three times too high.
The immortal author of the 'Mecanique Celeste' (t. v., p. 14) was led to
this conclusion by hypothetical views as to the mean depth of the sea. I
have shown ('Asie Centr.', t. i., p. 93) that the old Alexandrian
mathematicians, on the testimony of Plutarch ('in Aemilio Paulo', cap. 15),
believed this depth to depend on the height of the mountains. The height of
the center of gravity of the volume of the continental masses is probably
subject to slight variations in the course of many centuries.
These numbers show the low level of norther regions. In Asia the vast
steppes of Siberia are compensated for by the great elevations of the land
(between the Himalaya, the North Thibetian chain of Kuen-lun, and the
Celestial Mountains), from 28 degrees 30' to 40 degrees north latitude.
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