12 



ON THE CAUSES OF THE 



from the north-west or between the north and west, the 

 currents set to the south-east or between the south and east." 

 — Rees' Cyclopedia. 



Davidson, in an account of his voyage in this part of the 

 world, says, — " From April to September the south-east 

 monsoon blows in Torres Straits, and the westerly monsoon 

 prevails during October and the five following months, and 

 these last winds blow so strongly as to close the passage of 

 those straits," (from the Pacific.) He also further states that 

 " the barrier reef extends from the coast of New Holland 

 (Australia) to that of Papua, (or New Guinea,) with numerous 

 gaps and entrances in it, which appear to be kept open by 

 the current that for six months in the year runs through 

 them from the Pacific to the Indian Sea, and in the contrary 

 direction during the other six." (p. 214.) It thus appears 

 that during one half of the year the wind blows from the 

 Pacific Ocean through these straits, and then the oceanic 

 current runs through them from the Pacific; but during the 

 other half the wind blows from the Indian Ocean, and then 

 the current runs with it from that ocean. If the solid land 

 in its rotation towards the east left the water behind, and gave 

 it an apparent motion towards the west, it most undoubtedly 

 would run westward here from the wide Pacific Ocean, in the 

 winter as well as in the summer, — from October to March, 

 as well as from March to October, — seeing that the rotatory 

 motion would always produce precisely the same effect. But 

 as it does not do so, we must conclude that it is the changing 

 wind that produces the currents which so uniformly change 

 with it. 



These accounts of the alterations of the oceanic currents 

 with the change in the direction of the wind, are mostly given 

 by writers who supposed that the rotation of the earth was 

 the great general cause of the currents, and they speak of the 

 altered direction of the water in the particular cases with 

 surprise. There is, therefore, every reason to place confidence 



