THE FIGURE OF THE EARTH. 29 



quite three times as great as the elevation of the highest of 

 our mountains above the sea's level, but it is almost five 

 times as great as that of the eastern plateau of Thibet. 



We ought here to observe that the results of the earth's 

 compression, which have been obtained by mere measure- 

 ments of a degree, or by combinations of the former with 

 pendulum measurements, show far less 24 considerable differ- 

 ences in the amount of the equinoctial bulging than we 

 should have been disposed at first sight to conclude from the 

 fractional numbers. The difference of the polar compres- 

 sions ( {-Q and -2^-0) amounts to only about 7000 feet in 

 the difference of the major and minor axes, basing the calcu- 

 lation on both extreme numerical limits; and this is not 

 twice the elevation of the small mountains of the Brocken 

 and of Vesuvius ; the difference being only about one- tenth 



24 It has often seemed to me as if the amount of the compression of 

 the earth was regarded as somewhat doubtful merely from our wish 

 to attain an unnecessary degree of accwacy. If we take the values of 

 the compression at ^, 7 -Lj, ^ t ^, we find that the difference of 

 both radii is equal to 10,554, 10,905, 11,281, 11,684 toises, or 67,488, 

 69,554, 73,137, 74,714 feet. The fluctuation of 30 units in the denomi- 

 nator produces only a fluctuation of 1,130 toises or 7,126 feet in the 

 polar radius, an amount which, when compared with the visible in- 

 equalities of the earthis surface appears so very inconsiderable, that I 

 am often surprised to find that the experiments coincide within such 

 closely approximating limits. Individual observations scattered over 

 wide surfaces will indeed teach vis little more than what we already 

 know, but it would be of considerable importance to connect together 

 all the measurements that have been made over the entire surface of 

 Europe, including in this calculation all astronomically determined 

 points." (Bessel, in a letter addressed to myself, December, 1828.) Even 

 if this plan were carried out, we should then only know the form of 

 that portion of the earth, which may be regarded as a peninsular pro- 

 jection, extending westward, about sixty-six and a half degrees from the 

 great Asiatic Continent. The steppes of Northern Asia, even the mid- 

 dle Kirghis steppe, a considerable portion of which I have myself seen, 

 are often interspersed with hills, and in respect to uninterrupted 

 levels, cannot be compared with the Pampas of Buenos Ayres, or the 

 Llanos of Venezuela. The latter, which are far removed from all 

 mountain chains and consist immediately below the surface of secon- 

 dary and tertiary strata, having a very uniform and low degree of den- 

 sity, might by differences in the results of pendulum vibrations, yield 

 veiy decisive conclusions in reference to the local constitution cf the 

 deep internal strata of the earth. Compare my Views of Naturt, 

 pp. 28, 2932. 



