G8 PHYSICAL GEOGRAPHY OF THE SEA, A^D ITS BIETEOROLOGY. 



the atmosphere, as it winds along the course of the stream. The 

 latent heat of this vapour when it is set free produces a still 

 greater rarefaction, so that we may imagine there is in the 

 atmosphere a sort of cast of the Gulf Stream, in which the 

 barometer often stands low, and into which, as into the equi- 

 noctial calm bolt (§ 175), the wind often blows from both sides. 

 In this fixct is probably to be found an explanation of the phe- 

 nomena alluded to above, viz. : that certain stoi-ms, both in the 

 Atlantic and in the United States, invariably make for the Gulf 

 Stream, and, reaching it, turn and follow it in its course some- 

 times entirely across the ocean. Hence, the interest that is 

 attached to a proper series of observations on the meteorology of 

 the Gulf Stream. 



179. Stonns of — dreaded hy seamen. — Sailors dread its storms 

 more than they do the storms in any other part of the ocean. It 

 is not the fury of the storm alone that they dread, but it is the 

 " ugly sea " which these storms raise. The current of the stream 

 running in one direction, and the wind blowing in another, 

 create a sea that is often frightful. 



180. Boutes formerly governed hy the Gulf Stream. — The influence 

 of the Stream upon commerce and navigation. — Formerly the Gulf 

 Stream controlled commerce across the x\tlantic by governing 

 vessels in their routes through this ocean to a greater extent 

 than it does now, and simply for the reason that ships are faster, 

 nautical instruments better, and navigators are more skilful now 

 than formerly they were. 



181. Difficulties ivith early navigators. — Up to the close of the 

 last century, the navigator guessed as much as he calcidated the 

 place of his ship ; vessels from Europe to Boston frequently 

 made Kew York, and thought the landfall by no means bad. 

 Chronometers, now so accurate, were then an experiment. The 

 Nautical Ephemeris itself was faulty, and gave tables which 

 involved eiTors of thirty miles in the longitude. The instru- 

 ments of navigation erred by degrees quite as much as they now 

 do b}^ minutes; for the rude "cross staff" and "back staff," the 

 " sea-ring " and " mariner's bow," had not yet given place to 

 the nicer sextant and circle of reflection of the present da}'. 

 Instances are numerous of vessels navigating the Atlantic in 

 those times being G°, 8°, and even 10° of longitude out of their 

 reckoning in as man}^ days from port. 



182. Finding longitude hy the Gulf Stream. — Though navigators 

 had been in the habit of crossing and recrossing the Gulf Stream 



