CHAP. IT MILD AECnC CUllATU^ W 



opening between South Africa and Austialia is ^erj wide, 

 and the tendency of the trade-winds would be to ooDoeo- 

 trate the currents towanls its north-western eiiraniij , 

 just where the two great channels above described fimiied 

 an outlet to the northern seas. As will be shown in <Nir 

 nineteenth chapter, there was probably, dnring the eariier 

 portion of the Tertiary period at least, seTec^lazge ^^J^^W 

 in the space between Madagascar and Soofh India ; but 

 these had wide and deep channels between dieni, and 

 their existence may have been favourable to the con- 

 veyance of heated water northward, by oonoenftnitiiig 

 the currents, and thus producing massive bodies ^imoynD^ 

 water analogous to the Gulf Stream of the AtlanticL^ 

 Less heat would thus be lost by evaporation and radiatkm 

 iu the tropical zone, and an impulse would be aajoired 

 which would carry the warm water iato the nordi polar 

 area. About the same period Australia was piobaUy 

 divided into two islands, separated by a wide channel in a 

 north and south direction (see Chapter XXIL), and 

 through this another current would almost certainly set 

 northwards, and be directed to the north-west by the 

 southern extension of Malayan Asia, The more insular 

 condition at this period of Australia, India, and Xorth 

 Africa, with the depression and probable fertility of the 

 Central Asiatic plateau, would lead to the Indisin Ocean 

 being traversed by regular trade-winds iostead of by 

 variable monsoons, and thus the constant vis a Uryo, 

 which is so efficient iu the Atlantic, would keep up a 

 steady and powerful current towards the northern purts 

 of the Indian Ocean, and thence through the midst of 

 the European archipelago to the northern seas. 



Now it is quite certain that such a condition as we have 

 here sketched out would produce a wonderful edect on the 

 climate of Central Europe and Western and Xorthem Asia. 

 Owing to the warm currents being concentrated in ioland 

 seas instead of beiag dispersed over a wide ocean like the 



^ By referring to our map of the Indian Ocean showing the sabmuuie 

 banks indicating ancient islands (Chap. XIX \ it will be eTident thmt the 

 south-east trade-winds — then exceptionally powerfiil — ^wonld cause a T«st 

 body of water to enter the deep Arabian Sea. 



O 



