WAS AUSTRALIA KNOWN ? 95 



that this continent was joined to Asia on the East, and to 

 Africa on the West. But, after all, to give up Ptolemy's 

 teaching on this point was but to return to Mela and older 

 classical authorities, who had conceived of the land of the 

 Antichthones not as a continent, but as a huge continental 

 island. No doubt, on this matter, Mela had shown better 

 insight than Ptolemy. 



In the second place, it seemed to the map-makers that 

 the authority of the ancient geographers was confirmed by 

 the authority of the new science. The laws of physics, 



argued Mercator in I569, 1 determine that the earth must (2) the 



,, . c f -,-1 ,, A scientific 



be in a state ot perfect equilibrium. An excrescence on belief that a 



one side of the globe must in the nature of things be balanced Southern 

 by an excrescence on the opposite side ; for otherwise the i s needed as 



constitution of the world could not hold together in its a m 



... ,. . .. . . . weight, 



centre ( ahoqum mundi constitutionem in suo centro non 



posse consistere "). If the ancient geographers had grasped 

 'this truth they could have proved that the existence of 

 America was a physical necessity, simply because a New 

 World in the West was needed to balance the Old World in 

 the East. And, in the same way, it was now reasonable to 

 assert that a huge unknown continent must, by reason of 

 physical necessity, exist in the South to balance the huge 

 known continents in the North. " Since Asia, Europe and 

 Africa are for the most part situated to the North of the 

 Equator, there must be under the antarctic pole a continent 

 so great that with the Southern parts of Asia, and the new 

 India or America, it should be a weight equal to the other 

 lands." z 



1 Rainaud, p. 314. 



2 My colleague, Professor Cotton, has kindly written the following 

 note on Mercator's argument : 



" Although the science of geology cannot even yet afford an explana- 

 tion of the distribution of continental masses and ocean basins which 

 amounts to a demonstration, there is ample evidence that Mercator's 

 hypothesis, suggestive as it was, has no real foundation. 



The geodetic measurements of the values of gravity in various 

 parts of the world have revealed the striking fact that the force of 

 gravity is greater in the oceanic regions than it is on the surface of the 

 continents. It is now generally accepted by geologists that this fact 

 has a genetic significance ; and that the depressions of the solid earth 

 in which the ocean waters now lie are due to the sinking in of the 



