162 William Libbey — Gulf Stream and Labrador Current. 



series of meteorologic observations ; and serial observations were 

 made on the temperature of tlie water at each of the several 

 stations. 



In the serial temperature work the thermometers were fastened 

 to a wire cable of 19 strands of number 24 crucible steel music 

 wire, with a breaking strain of 1,500 pounds. The interval be- 

 tween the instruments varied'as the depth increased. They were 

 placed closer together where the changes were quickest — i. e., 

 near the surface — and Avhere the temperatures became more 

 regular they were placed further apart. We onW adopted a 

 regular system for the distribution of the thermometers along 

 the cable after having examined the whole area to be studied 

 from north to south along several lines and were sure that all 

 the facts were covered by the system. 



The area was studied by running out a series of lines 10 miles 

 apart, along which at intervals of 10 miles the stations were made- 

 These lines were repeated as often as possible, and temperature 

 profile curves were plotted along these lines, based on the observa- 

 tions made at the stations. On most of these temperature pro- 

 files we have given the curves of 70°, 60° and 50° as being the 

 most important. 



The 50° curve has been an interesting one from the beginning, 

 as it was the means of showing us that there were two sets of 

 conditions under which the two measurably distinct bodies of 

 water came in contact. 



It will be convenient to speak of these two portions of the 

 main current of the Gulf stream separately. I shall therefore 

 speak of the upper portion first. 



/. Upper Portion. 



The boundary between the cold and the warm currents of the 

 surface is ver}'- seldom a straight line, perpendicular to the sur- 

 face. It marks the position of the resultant of all the forces at 

 work. Of course the general position of the boundary will be 

 determined by the velocities of the two bodies and the direction 

 of their currents when they come in contact. 



If we leave out of consideration the wind as an efiective agent 

 in the production and directing of the oceanic currents, Ave find 

 that it becomes a most potent factor in the clianges wliich are 



