30 MAGNITUDE, FIGURE, AND 



; the increase of the radius of the earth at the 

 equator, ( 23 ) in comparison with that at the poles, is the 

 difference between 3272077 and 3261139 toises ; being 

 10938 toises, or 65628 Paris, or 69943 English, feet, or 

 not quite 11 \ geographical miles. As it has been customary 

 to compare this equatorial convexity of the earth's surface 

 with well-measured mountain-elevations, I select as objects 

 of comparison the highest known summit of the Himalaya, 

 Kinchinjunga, 4406 toises, 26436 Paris or 28178 English 

 feet, as measured by Colonel Waugh, and that part of the 

 Plateau of Thibet which is nearest to the Sacred Lakes, Rakas- 

 Tal and Manassarovar, and which, according to Lieut. Henry 

 Strachey, attains the mean elevation of 2400 toises, or about 

 15347 English feet. It would follow from hence that the 

 enlargement of our planet in its equatorial zone is not 

 three times as great as the elevation of the summit of the 

 highest terrestrial mountain above the level of the sea, nor 

 five times as great as the general elevation of the Eastern 

 Plateau of Thibet. 



This is the proper place for remarking that differences 

 between the results obtained for the amount of the earth's 

 ellipticity by measurements of degrees taken alone, and by 

 the combination of measurements of degrees and pendulum 

 experiments, are actually far smaller than we might be 

 inclined to suppose at the first sight of the fractions in 

 which those results are expressed. ( 24 ) The difference 

 between -g-J-o- and -^l-o- as the extreme results for the in- 

 equality of the equatorial and polar axes, is little more than 

 6600 Paris (7034 English) feet: not twice the height of 

 such small mountains as Vesuvius and the Brocken. 



