SUEFACE WATEES OF THE NOETH ATLANTfC OC’EAN. 
83 
a strong increase of salinity without any corresponding change of temperature in the 
south-eastern region, and a distinct lowering of temperature and salinity in the north¬ 
east. 
April, 1896.—The area covered by the observations for this month is largely 
increased by the records of the whaler “ Active,” and vessels trading to Greenland. 
In the south-west the isothermal of 15° reappears in the Gulf Stream region, and 
north of this the temperature gradient is exceedingly steep, for the 5° line retains the 
position of the previous month. Further east, in long. 50° W., temperature has 
fallen, the 15° line disappears, the 10° and 5° lines are jD^cked close together, and the 
0° isothermal comes dovm to lat. 45°. In mid-Atlantic the 15° line has moved north¬ 
ward, chiefly in the region of long. 25° to 30° W., where it appears in about lat. 45°, 
and it continues in lat. 40° to 42° to the Portuguese coast. There is a distinct rise of 
temperature west and north-west of the British Isles—the 10° isothermal touches 
the north-west of Ireland, and the 8° line has recovered its February position. 
The 5° line starts at the south-eastern corner of Iceland, runs to just nortli of the 
Faeroe Islands, turns north-east till it cuts the meridian of 0° in al)out lat. 64° N., and 
then goes north to lat. 7 0°, wliere it turns eastwards. The line of 0° follows a similar 
course somewhat to the north-west of the 5° line, hut north of 72° it bends repeatedly, 
recrossing the meridian of 10° E. several times, the warmer water lying always to 
the eastward. 
Temperature has apparently undergone little change to the west of Iceland, the 5° 
line starting from about the middle of tlie western coast. To tlie south and south¬ 
west of Greenland tlie isotliermal forms a tongue pointing W. and N.AV., temperature 
0° to 5° ; further up Davis Strait there are very low tenpieratures near the land. 
In the eastern region the chief changes in salinitv are a marked fall off the coast 
of the United States and a rise in about long. 58° AV., making the lines run more 
S.AV. and N.E., and packing them closer together. Between the 40th and 50th 
meridians all the lines have moved south-eastward, the 36 line a little, the 35 and 34 
lines moi'e, hence the gradients are steeper. In the south-eastern region the position 
of the 36 line last month is confirmed, and tlie 35‘5 line remains unaltered. 
A narrow belt running tlirough the Faeroe-Shetland Channel, and apparently 
widening out beyond it, is enclosed by the 35‘3 line. Tlie 35 line skirts the coasts of 
the North Sea and the entrance to tlie Skagerak, and then sweeps westward to the 
meridian of 0° in about lat. 64° N. liefore finally turning N.E. Another branch of it 
runs close to the south of Iceland, and then apparently turns slowly to the north-east 
to form the north-western border of a wide lielt which runs eastward to the noi'th of 
Norway and spreads northwards and westwards to Spitsbergen and the meridian 
ofl0°E. 
It would seem that between Iceland and the Faeroe Islands the freshening of the 
surface water noticed last month continued; and that west of Iceland salter waters 
appeared farther north. The S-shaped form of the 35‘0 and 35'3 lines in mid-Atlantic 
2 
