Vol. 59.] THE FIGURE OF THE EARTH. 185 



morphological centre of Asia. Let us join this by the arc of a 

 great circle passing through it and the East Indian centre, and 

 complete the circle. It will he found to pass so close to the 

 Caucasian centre, which determines one great arc of the Eurasian 

 folding, as to be practically coincident with it, and it passes equally 

 near the great Icelandic centre which determines the Atlas-Crimean 

 arc. This circle may therefore be regarded as the directive circle 

 for the Eurasian folding, just as that joining the East Indian and 

 Aleutian centres was for the Pacific belt. In its further course, 

 after crossing the Atlantic it runs through the whole length of 

 South America, crosses the Antarctic continent, and just touching 

 the west coast of Australia, with the northern half of which it is 

 coincident, returns to the East Indian centre. 



The two main directive circles, the Eurasian and Pacific, intersect 

 at an angle of 39° ; if now we finally draw another great circle 

 midway between them, bisecting this angle we shall obtain a mean 

 directive, the pole of which will determine as high a degree of 

 symmetry as is discoverable in the features of our planet. This 

 pole is situated on the great circle passing from north-north-west to 

 south-south-east through Africa, near the sources of the White Nile, 

 6° north of the Equator. It lies on the same great circle as that 

 which we had provisionally obtained, but 21 c nearer the Equator. 

 The axis of terrestrial symmetry thus passes through the middle of 

 Africa on the one side, and of the Pacific Ocean on the other. 



This result acquires additional value from the conclusions of 

 geodesists, who find that the terrestrial figure which best represents 

 the results of geodetical measurements gives to an equatorial 

 diameter passing through Africa a length appreciably in excess of 

 one directed at right angles to it. The point where this axis 

 intersects the surface is given by Capt. Clarke as being situated in 

 long. 14° 23' E., but by Gen. Schubert in long. 41° 4' E. Our morpho- 

 logical pole is situated midway between these points, in long. 28° E., 

 lat. 6° N. If a charted globe be mounted on an axle corresponding 

 with the morphological axis, and an equator to this axis be drawn 

 round it, the symmetrical distribution of land and sea will be 

 readily apparent. Africa, as we have seen, forms the summit of 

 one hemisphere ; the smallest circle that will circumscribe it has a 

 centre 2 or 3 degrees west and north of the morphological pole; 

 points separated by 120° upon it are the Cape of Good Hope, 

 Cape Blanco, and Kedji in Baluchistan. If we regard this circle 

 as marking the boundaries of the original African dome, now 

 fractured and fallen in, we perceive a certain amount of symmetry 

 still persisting in the remainder, the extension southward to the 

 Cape of Good Hope forming one arm of a trilobed mass, that to 

 the east-north-east a second, and that through Arabia and Persia a 

 third, but this is broken across by the Red Sea and the Persian Gulf. 

 Between these lobes we have, in the case of the first and second, a 

 great piece of the dome swallowed up by the Atlantic, only small 

 volcanic islands like Ascension and Tristan d'Acunha rising over its 

 Q. J. G. S. No. 234. o 



