From St. Thomas to Halifax. 65 



the meridian of long. 65° W., from St. Thomas, in the West 

 Indies, to Halifax in Nova Scotia, the group of the Bermudas 

 dividing the section into two nearly equal halves (Plate 2). An 

 examination of the isotherm of 20° C, as well as of the surface- 

 temperatures, shows that, between Station 27 and Station 28, 

 we cross the northern limit of that portion of the North Atlantic 

 Equatorial Current which flows outside the West Indian Islands. 

 Reduced in depth, the warm surface-stratum continues towards 

 the Bermudas, beyond which group it suffers further reduction 

 by coming in contact with the Labrador current. At the 

 station of the 24th May, we once more fall in with the 

 equatorial current, namely, that portion of it which, after 

 entering the Caribbean Sea and after making the circuit of 

 the Gulf of Mexico, issues out of the latter through the Strait 

 of Florida and flows along the U.S. coast under the name of 

 the Gulf Stream. At the above station, the " Challenger " found 

 a surface-stratum 50 fathoms thick of a nearly uniform tem- 

 perature of 22°.8 C, only i°.6 C. below the surface-temperature 

 of the current outside the West Indies. At Station 52 we 

 encounter the " cold wall " of the Labrador current, against which 

 the Gulf Stream banks itself up during the whole of its course 

 along the American coast; and at Station 51 and Station 50 

 we observe the rapid fall of temperature due to this cold 

 current. 



Those who have effaced the Gulf Stream off the Banks 

 of Newfoundland, and have attributed to the North Atlantic 

 Equatorial Current, or "North Atlantic drift-current" as it has 

 been called, the vast masses of warm water which occupy the basin 

 of the North Atlantic as far north as Spitzbergen and Baffin 

 Bay, and those who supported the opposite theory giving all the 

 credit to the Gulf Stream, were probably both partly right and 

 partly wrong in their conclusions. The " Challenger" observations 

 leave little doubt but that the Gulf Stream is a branch of the 



