108 



less the body of warm salty water which bathed the slope inshore on 

 this section had its source in the inner edge of the Gulf Stream, the 

 development of this invasion is plainly discernible on the horizontal 

 charts of circulation. The increased number of isosteres in the 

 profile of specific volume (fig. 40), over what were present in this 

 locality six weeks earlier (fig. 30) represents the influence of increased 

 solar warming of the surface layers. 



Section VII: A connection with the warm salty water observed in 

 Figure 39, is to be observed in this section (fig. 41) at the slope 

 stations. The high temperatures and salinities at the two outer 

 stations plainly indicate that the northern edge of the Gulf Stream 

 then lay approximately 75 miles off the southwest slope. The 

 density wall (fig. 42) was 20 to 25 miles inshore of the cold wall. 



Section VIII : Again in this section we see a trace of tropical water 

 along the southwest slope wedged in against the bank. The density 

 wall at the Tail was about 30 miles inside of the temperature wall. 



Sections IX and X exhibit no unusual characteristics from those 

 observed in earlier sections at the same places. 



DISCUSSION OF THE CIRCULATION IN THE HORIZONTAL PLANE 



The total of 76 stations have, for the purposes of horizontal illus- 

 tration, been divided into three groups which are separated from one 

 another by a space of at least two weeks in time. They have been 

 arranged as follows: 



Set I: April 29 to May 5, a total of 25 stations embodied in Figures 

 49, 50, 51, 52. 



Set. II: May 18 to 20, a total of 13 stations embodied in Figures 

 53, 54, 55, 56. 



Set III: June 25 to 29, a total of 27 stations embodied in Figures 

 57, 58, 59, 60. 



SET I 



The 175 density values obtained from 25 stations, 558 to 583, 

 taken April 29 to May 5, were subjected to mathematical computa- 

 tions described in United States Treasury Department Bulletin No. 

 14, giving the values shown in the last four columns in the oceano- 

 graphic station table, page 78. Since we assumed that the maximum 

 depth of observation, 750 meters (or decibars), was a level isobaric 

 plane, the dynamic values of 728+ given on the charts (figs. 49, 53, 

 and 57) represent the height of the sea surface in dynamic meters 

 at each station. (See Oceanographic station table, p. 78, for a 

 detailed record of these data.) The dynamic heights have been 

 plotted at the proper station positions on Figure 49, page 109, and 

 contour lines delineating the topography of the sea surface were 

 drawn in similar fashion to those which appear on an ordinary 



