GULF STREAIM, CLIMATES, AND COMMERCE. 65 



Bernini to the Grand Banks is constantly sending up volumes 

 of steam; this, being lighter than air, produces a channel way 

 of rarefied air through 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 belt (§ 175), the wind often blows from both sides. In 

 this fact is probably to be found an explanation of the phenomena 

 alluded to above, viz. ; that certain storms, both in the Atlantic 

 and in the United States, invariably make for the GuK Stream, 

 and, reaching it, turn and follow it in its course sometimes entirely 

 across the ocean. Hence, the interest that is attached to a jjroper 

 series of observations on the meteorology of the Gulf Stream. 



179. Sailors dread its storms more than they do the storms in 

 storms of-dreaded ^uy othcr part of the ocean. It is not the fury of 



^ea " which these storms raise. The cmTent of the stream run- 

 ning in one dfrection, and the wind blowing in another, create a sea 

 that is often frightful. 



180. The influence of the Stream upon commerce and naviga- 

 iioutes formerly tioii. Fomierlv the Gulf Stream controlled com- 



guverned by the j_l * xl j.- "l • i • 



Gulf Stream. mcrco across the Atlantic by governmg vessels m 



their routes through this ocean to a greater extent than it does 

 now, and simply for the reason that ships are faster, nautical in- 

 struments better, and navigators are more skilful now than for- 

 merly they were. 



181. Up to the close of the last centmy, the navigator ^^tessetZ 

 Difficuitips with as much as he calculated the place of his ship ; ves- 

 eariy navigators. g^jg ^^^^ Europo to Bostou fr^cqucntly maclo Kew 

 York, and thought the landfall by no means bad. Chronometers, 

 now so accurate, were then an experiment. The Nautical Ephem- 

 eris itself was faulty, and gave tables which involved errors of 

 thirty miles in the longitude. The instruments of navigation 

 erred by degrees quite as much as they now do by minutes ; for 

 the rude " cross staff " and " back staff," the " sea-ring " and " mari- 

 ner's bow," had not yet given place to the nicer sextant and circle 

 of reflection of the present day. Instances are numerous of 

 vessels navigating the Atlantic in those times being 6,8, and 

 even 10° of longitude out of their reckoning in as many days fr'om 

 port. 



p 



