7-i PHYSICAL GEOGllAPUir OF IzIE SKA, AND ITS METEOROLOGY. 



vray. He makes great use of them. General Sabine, in his 

 passage, some years ago, from Sierra Leone to New York, was 

 drifted one thousand six hundred miles of his way by the force 

 of currents alone ; and, since the application of the thermometer 

 to the Gulf Stream, the average passage from England has been 

 reduced from upwards of eight weeks to a little more than four. 

 Some political economists of America have ascribed the great 

 decline of southern commerce which followed the adoption of the 

 Constitution of the United States to the protection given by 

 federal legislation to northern interests. But I think these 

 statements and figures show that this decline was in no small 

 degree owing to the Gulf Stream, the water-thermometer, and 

 the improvements in navigation ; for they changed the relations 

 of Charleston — the great southern emporium of the times — 

 removing it from its position as a half-way house, and placing it 

 ill the category of an outside station. 



191. TJie scojpe of these researches. — The plan of our work takes 

 us necessarily into the air, for the sea derives from the vsdnds 

 some of the most striking features in its physical geography; 

 and from the air all of its meteorology. "Without a knowledge of 

 the winds, we can neither understand the navigation of the 

 ocean, nor make ourselves intelligently acquainted with the 

 great highways across it. As with the land, so with the sea ; 

 some parts of it are as untravelled and as unknown as the great 

 Amazonian wilderness of Brazil, or the inland basins of Central 

 Africa. To the south of a line extending from Cape Horn to the 

 Cape of Good Hope (Plate VIII.) is an immense waste of waters. 

 None of the commercial thoroughfares of the ocean lead through 

 it ; only the adventurous whaleman finds his way there now and 

 then in pursuit of his game ; but for all the purjDoses of science 

 and navigation, it is a vast unknown region. Nov\^, were the 

 prevailing winds of the South Atlantic northerly or southerly 

 instead of easterly or westerly, this unploughed sea would be an 

 oft-used thoroughfare. Na}^, more, the sea supplies the wind 

 with food for the rain which these busy messengers convey 

 away from the ocean to " the springs in the valleys which run 

 among the hills." To the philosopher, the . places which suppl}^ 

 the vapours are as suggestive and as interesting for the instruc- 

 tion they afford, as the places are upon which the vapours are 

 showered down. Therefore, as he who studies the physical 

 geograph}- of the land is expected to make himself acquainted 



