30 TEE G ULF STREAM. 



tions, the Gulf Stream has a velocity, at times, of five miles 

 an hour, pouring on like an immense torrent. 



The cause of these phenomenal ocean river currents, up 

 to the present time, is only conjectured, and the nature and 

 extent of this work will hardly warrant any extended theo- 

 retical discussion. 



Each current seems to have a circulation of its own, t.e., 

 an upper and lower stratum. In the warm currents, the 

 upper portion only is warm, while beneath runs a counter 

 cold current. In the cold currents, the order of stratums is 

 reversed. 



There is a constant tendency of polar waters toward the 

 tropics, and of tropical waters toward the poles. 



It is a custom often practiced by seafaring people to 

 throw a bottle overboard, having inside a paper, stating the 

 time and place at which it is done. These minute little 

 vo^^agers leave no trace behind them, and therefore their 

 routes cannot be exactly ascertained, though we can approx- 

 imate closely, knowing where they were cast and where they 

 were found. Charts have been prepared showing the routes 

 of over one hundred bottles, by drawing straight lines from 

 the starting to returning point, with the time elapsed. From 

 this it appears that the waters from every quarter of the 

 Atlantic tend towards the Gulf of Mexico and its stream. 

 Good circumstantial evidence exists to prove that bottles 

 cast overboard in the Gulf Stream have performed the entire 

 tour of that current. 



Other currents as well as the Gulf Stream are utilized in 

 a similar manner. As an instance of this we quote the in- 

 structions of Mr. G. M. Robeson, Secretary of our Navy, to 

 C apt. Francis Hall, of the Polaris expedition in 1869, as fol- 

 lows: " To keep the Government as well informed as possible 

 of your progress, you will, after leaving Cape Dudley Digges^ 

 throw overboard daily, as open water or drifting ice may 

 permit, a bottle or small copper cylinder, closely sealed, con- 



