1 16 HYDROGRAPHY. 



surface, the salinities at the bottom are very different, respectively 35*31 and 34'99- From this will be 

 seen, that at the beginning of June, at which period the stations 16 and 15 have been taken, the 

 eastern branch of the Irmmger Current was still smaller than in August 1896, the time of observation 

 for the stations 89 and 99. Even if this branch of the Ir winger Current being of little extent, the 

 determinations prove distinctly that it exists, and show to what extent the Atlantic- 

 water is led over the Iceland-Greenland ridge from the southward. 



That the East Greenland Polar Current is bringing water from the northward over the ridge 

 is a well known fact , and as this current is a surface current , such a thing must take place in or 

 near the surface. Several determinations imply, however, that water in the depth, even if it be in 

 the vicinity of Iceland, also can pass over the ridge from the northward. This can be seen by the 

 temperatures at the bottom at the stations 96 and 95, which are respectively i°2 and 2°i. Such low 

 temperatures cannot be supposed to be due to such a thing as Atlantic-water — cooled in the western 

 part of the Denmark Strait — being led to these stations by the rotation, for in that case we should 

 be able to find at least as low temperatures more southerly in the Denmark Strait, which is not the 

 case. That the temperature at the bottom rises so quickly to the southward, must therefore be 

 regarded as sufficient to prove that the cold bottom-water, found in a small quantity south 

 of the Iceland - Greenland ridge, has made its way over the ridge from the 

 northward. 



The salinity at station 128 is at several depths less than 35 - oo. Only at the bottom, and at a 

 depth of 50 fathoms (94 metres), a salt stratum of water is making its way from the westward into 

 the less salt layer of water. At station 127 (it is not in section XIII) which is a little more southerly 

 than station 128, the salinity at the bottom at a depth of 44 fathoms (83 metres) is seen to be 35'07. 

 By this it becomes an established fact, that even if the branch of the Irmmger Current, which runs 

 in an easterly direction, being of very little breadth and strength, it cannot be denied that it exists, for 

 how should we otherwise be able to account for the salinity that is increasing towards the land. 



That the salt water west of the stations 127 — 128 sends a layer of water in an easterly direction 

 into the more fresh water at a depth of 40 — 50 fathoms (75 — 94 metres), must no doubt be a regular 

 consequence of the differences of specific gravity. It is, as we know, warm and salt Atlantic-water, and cold 

 Polar-water of less salinity that meet one another here, and on account of this, the boundary surface 

 between these two species of water will not be able to maintain its position as a vertical plane, for 

 the specific gravity of the Atlantic-water exceeds that of the ice-water which forms the upper layer of the 

 Polar-water, and it is less heavy than the cold and rather salt stratum, which is the lowermost layer 

 of the Polar Current. Owing to this, the Atlantic-water will make its way in between the two strata 

 of the Polar-water, while one of these two is floating above, and the other below the Atlantic-water. 

 As the difference of specific gravity is greater for Atlantic-water and ice-water than it is for the At- 

 lantic-water and the under-layer of the Polar-water, the cold and fresh ice-water will flow farther over 

 the Atlantic-water, than the under-layer of the Polar-water will flow in under the Atlantic-water. The 

 isohaline 35-00 in section XIII just implies that this is the case in so far as this section is concerned. 



This way of reasoning may be applied everywhere where two kinds of water — with a diffe- 

 rent vertical distribution of the specific gravity — meet, still it is to be observed that this only can 



