§ 191. GULF STREAM, CLIMATES, AND COMMERCE. gg 



really felt but for a few hours during the interval, could only be 

 proportioned out equally among the whole number of days. 

 Therefore navigators could have only very vague ideas either as 

 to the strength or the actual limits of the Gulf Stream, until they 

 were marked out to the ]N'antucket fishermen by the whales, or 

 made known by Captain Folger to Dr. Franklin. The discovery, 

 therefore, of its high temperature assured the navigator of the 

 presence of a current of surprising velocit}^, and which, now turn- 

 ed to certain account, would hasten, as it had retarded his voyage 

 in a wonderful degree. Such, at the present day, is the degree 

 of perfection to which nautical tables and instruments have been 

 brought, that the navigator may now detect, and with great cer- 

 tainty, every current that thwarts his way. He makes great use 

 of them. Colonel Sabine, in his passage, a few 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 upward 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 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-ther- 

 mometer, 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 in the category of an outside station. 



191. The plan of our work takes us necessarily into the air, for 

 The scope of these ^hc sca dcrivcs from the winds some of the most 

 researches. striking featurcs in its physical geography. With- 



out a knowledge of the winds, we can neither understand the 

 navigation of the ocean, nor make ourselves intelligently ac- 

 quainted with the great highways across it. As with the land, 

 so with the sea ; some parts of it are as untraveled and as un- 

 known 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 YIII.) is an im- 

 mense waste of waters. None of the commercial tJiorougb fares 



