420 OBSEEVATIONS ON THE CUEEENTS. 



charts, show, as Dr. Petermann says, that the Polar waters set against 

 and penetrate it hke an immense wedge.* This cold-water gulf penetrates 

 for 150 to 200 miles Southward of its general limit ; and in July, which is 

 the period when the Arctic Ice drifts down in the greatest quantities, this 

 is most evident, as the Arctic water is not more than 48°, while that of the 

 Gulf Stream to the Southward is 68° and upwards. In January, the period 

 when the Arctic regions are entirely frozen, and no Icebergs descend into 

 these Southern latitudes, the effects on the surface are not quite so mani- 

 fest, but are equally evident as far South as lat. 38° N. 



Now, this " cold-water gulf " is no surface interference of a temporary 

 nature. It is a strong permanent current, flowing to a greater depth than 

 the Gulf Stream at all seasons of the year. That it entirely outs off all 

 the lower beds of the warmer water is demonstrated by the fact that Ice- 

 bergs, 80 and 100 feet high, have been seen as far South as lat. 36^ 10' N. 

 in April, 1829, and 38° 40' in June, 1842. This shows that the more 

 powerful Southern Arctic Drift, of which many evidences are constantly 

 met with, in the summer months by the Ice-drifts, and in the winter by 

 the cold water, must cut off the Eastward progress of this Northern portion 

 of the Gulf Stream waters. It is very probable that a small portion of 

 the warm water does get over to the Eastward of this in the "hot streaks" 

 which are so remarkable ; because, although the thermometer on the 

 surface shows that there is no continuity in the waters on the East side of 

 long. 48° with those to the West of that meridian, yet the current observa- 

 tions show that the drift is still, generally, to the Eastward. f 



(411.) In January, 1890, Captain Williams, of the steamer Montana, 

 bound Eastward, made some temperature observations of the surface 

 water, and at a depth of 15 feet, showing a marked drop Southward of 

 the Banks, between lat. 40° 40' and 41° 40' N., long. 52° and 48° W. 

 Between 8 p.m., on January 23rd, and 4 a.m. on the 24th, the sub-surface 

 temperature fell from 70° F. to 40°, and in the next 12 hours rose again to 

 70°, the distance traversed being about 200 miles. The maximum surface 

 temperature was 64°, the minimum also 40°, the latter being found about 

 the 61st meridian. 



(412.) The position, depth, and angle of meeting of the Gulf Stream and 

 Arctic Current is continually changing. Small differences in density will 

 determine which water will over-ride the other, causing alternations of 

 temperature, both horizontally and vertically. Not only are the alterna- 

 tions found within the supposed limits of the Stream, but also both inside 

 and outside of it. 



Possibly at times, owing to its greater density, the warm water of the 



• Mittheilungen, 1872, page 220 ; Knorr, page 43. 



t It is quite certain that the surface motion is not of any great depth, and that at a 

 few fathoms beneath the surface it is inappreciable to any ordinary mechanical means. 

 There is direct evidence of this in the deep-sea sounding trials, and more especially in 

 the electric cable-layiug experience. In these, if there should be any under-currents of 

 force or in difierent directions, it would be shown directly by their action on the sub- 

 merged line. In the case of the telegraph cables, the refined dynamometric apparatus 

 employed is, generally, so uniform in its evidence, that the question of sub-surface 

 action may be said to have been settled by it. 



