AMELIORATIONS OF PRESENT ARCTIC CLIMATES 399 



gasso area. A slight amount of the increase in the salinity of the 

 Gulf Stream east of North America may be assigned to excess of 

 evaporation over precipitation in crossing ''the 30° dry belt," but 

 the amount of this seems insufhcient to explain the salinity repre- 

 sented on Murray's map. The data seem to imply that there is 

 a reciprocal action between the saline waters of the main evaporat- 

 ing or Sargasso Basin and the adjacent edge of that part of the 

 Gulf Stream which circles about it, by which the two classes of 

 water are intermingled or interdigitated. The waters of the Gulf 

 Stream proper are the fresher and Hghter; the waters of the Sar- 

 gasso region are constantly growing more saline by reason of excess 

 of evaporation over precipitation. Under these conditions an inter- 

 action of the two types of waters is likely to take place, assuming the 

 form of spiraloid currents subordinate to the main movement of the 

 encircHng Gulf Stream. There would naturally attend this an 

 intermixture or interweaving of waters of a complicated digitate, 

 gyratory sort. This view gains not a little support in the anoma- 

 lous drifts of wreckage. While the Gulf Stream has a very definite 

 northeasterly movement in this region, the drifts of wreckage are 

 often very strangely at variance with it in details. These pecuhari- 

 ties imply that the Gulf Stream, when studied in detail, is far from 

 being a simple, straightaway current. It seems to be affected by 

 whirls and various anomalous movements of a minor sort. The 

 singular northeastward extensions of the 26°-per-mille sahnity Kne 

 (see salinity chart, Fig. 2), at about 20° West Long, in mid-ocean, 

 fall in with this view. This feature seems rather clearly to imply 

 that the edge of the sahne waters of the evaporating area are 

 involved in the northeastward movements of the adjacent Greater 

 Gulf Stream. At any rate, this view seems best to fit the distribu- 

 tion of supersahne waters compared with subsaline waters of the 

 mid-Atlantic, so far as now known. We shall return to this subject 

 in considering the middle stratum of the Atlantic column. 



When a little past the middle of the Atlantic, the Gulf Stream 

 sends off a southward, recurving branch, which flows around the 

 east end of the Sargasso area and connects with the North Equa- 

 torial current and thus at length completes the loop about the Sar- 

 gasso Basin. It is important here to note also that, on its outer 



