304 LIGHT SCIENCE FOR LEISURE HOURS. 



posing these arrangements to exist, it is evident that 

 they form mere local peculiarities. The general tend- 

 ency of water towards the southern hemisphere is very 

 obvious, and, so far as I am aware, no other explanation 

 of the peculiarity has ever been offered than that founded 

 on a slight displacement southwards of the earth's 

 centre of gravity. If, then, C is the centre of the black 

 circle in Fig. 3, representing the solid part of the 

 earth, the centre of gravity of this part lies (in the Fig.) 

 slightly below C between C and C', let us suppose. 



Now we see that, owing to this slight displacement, 

 the watery envelope of the earth tends southward. If 

 the earth were a perfectly uniform spheroid, it is clear 

 that there would be a tendency to some such arrange- 

 ment as is represented (on a greatly exaggerated scale) 

 in Fig. 3, in which the shaded part represents the sea 

 that is, a shell of water, thicker towards the south, 



probable one. The theory of an antarctic continent is hardly in the 

 same position, since antarctic explorations have given us but faint indi- 

 cations, here and there, of the habitudes of the south-polar regions. 

 But I may note, in passing, a very singular argument used by Captain 

 Maury in favour of the existence of such a continent. He states it as 

 a physical law that land is scarcely ever antipodal to land ; ' therefore,' 

 he says, ' since the north-polar regions are probably occupied by a vast 

 ocean, the south-polar regions are probably occupied by a vast con- 

 tinent.' He seems to forget that it by no means follows that because 

 land is seldom antipodal to land, water should seldom be antipodal to 

 water. Since the extent of water is nearly three times that of land, it 

 is absolutely necessary that nearly two-thirds of the water should be 

 antipodal to water. The supposed peculiarity that nearly all the land 

 is antipodal to water (one twenty-seventh only being antipodal to land), 

 is in reality no peculiarity at all. It would have been far more singular 

 if any large proportion of the land (which occupies little more than one- 

 fourth of the globe) had been antipodal to land. 



