264 THE ATLANTIC. [chap. v. 



The main feature in the section was the steady increase to the 

 westward of the temperature of the surface-layer, the isotherm- 

 obaths of 19°, 20°, 21°, 22°, 23°, and 24° C. being added in regu- 

 lar succession. This was due chiefly to the southward direction 

 of the section, partly to the advance of the season, and partly 

 to the westward determination of the warm surface-water. 



From St. Thomas to Bermudas the surface-temperature nat- 

 urally fell gradually, the lower lines remaining pretty steady ; 

 but at Station XXYIII., lat. 21° 39' N., long. 65° 25' W., a 

 very marked widening of the space between the isothermobaths 

 of 18° and 19° C. was observed, and, farther on, the whole of 

 the space between the lines of 16° and 19° C. became abnor- 

 mally expanded, indicating the presence of a layer of water 

 200 fathoms thick, considerably above its normal temperature, 

 lying between the 100 and the 300 fathom line. This warm 

 band appeared again to the north of Bermudas, and on our 

 north-westerly course toward Sandy Hook (Plate XL) it main- 

 tained its volume and position to lat. 36° 23' N., long. 71° 

 51' W., when it came to the surface, or became merged in the 

 phenomena of the Gulf-stream. 



We next crossed the Gulf-stream, of which I have nothing 

 further to say than that all we saw confirmed our previous con- 

 victions as to its cause and its effects ; and we sounded in the 

 Labrador Current, the local and most insignificant return stream 

 from the Arctic Sea. 



On our return from Halifax to Bermudas (Plate IX.), we 

 again encountered the warm band at Station LTL, lat. 39° 44' 

 N., long. 63° 22' W., and traced it all the way to the island. 

 To the east of Bermudas it again made its appearance on our 

 section from Bermudas to the Azores (Plate XYL), and main- 

 tained its volume to Station LXX., lat. 38° 25' N., long. 35° 50' 

 W., where it became less definite, and then thinned out, while 

 at the same time the lower isothermobaths began to dip down 

 and to separate, indicating an enormous accumulation of super- 



