13° 



HYDROGRAPHY. 



On the other hand, the isotherms that are crowded together at the bottom, as well as the 

 nethermost 35*25 isohaline, prove that nearly the whole of the layer at the bottom in this section is 

 consisting of North Ocean Water. On top of this is a layer with a salinity that is higher than 3525, a 

 layer constituting the greater part of the water in section XXIV, and which must be due to Atlantic- 

 water. Finally we find at stations 133 and 135 a stratum of ice-water, which certainly does not offer 

 any marked features, but this is perhaps on account of observations being wanting from stations 135. 

 It can be seen then from what has been said, how in this section Atlantic-water is forcing 

 itself in among the upper and under-layer of the Polar-water; the same applies to 

 section XIII, where the 35*25 isohaline in the shape of an arc makes its way in between the same 

 two strata of water. 



The three last sections XXII, XXIII and XXIV cross the boundary between the water 

 of the Atlantic and water from the East Icelandic Polar Current. This boundary must be a 

 surface of a very complicated shape. Isotherms and Isohalines are in each section drawn independently 

 of the two others, which, though it cannot be considered as quite correct, has been done to facilitate 

 the view. We find in section XXIV, which is lying south of section XXII, a layer of ice-water at 

 the surface, the existence of which could scarcely be accounted for, if it was not likewise to be found 

 in XXII. This latter does not, however, show us anything by which the origin of the ice-water can 

 be traced, and I have therefore entirely omitted to put down ice-water in section XXII. With respect 

 to this must be observed that section XXII is constructed according to observations made, partly in 

 1895 and partly in 1896. This is at least, in so far as the upper-layer is concerned, not justifiable, as 

 we must take it for granted that the extent of the ice-water alters during the different seasons and 

 from one year to the other. Nor could such a proceeding be considered as right in so far as regards 

 the deeper situated layers, as Atlantic-water is here getting mixed with Polar-water; furthermore we 

 cannot consider it as an established fact that the currents in the depth should be the same at 

 different times. 



Although, on account of the few observations, the sections do not give us minute information 

 about the actual state of matters above this ridge, we may for all that through section XXI be able 

 to form an idea of the further course of the western part of the East Icelandic Polar Ctirrent. In this 

 section the isohaline 35 - oo is seen to incline downwards at station 59, nearly down to the o° isotherm, 

 which at the same place has a considerable inclination upwards .This shows that the under-layer does 

 not hegin here before at a great depth, and that it has a lower temperature here than farther north. 

 Owing to this, this under-layer cannot be due to Atlantic-water flowing in. a northerly direction, for if 

 such a thing being the case, the temperature of the under-layer would be decreasing instead of in- 

 creasing to the northward. We must therefore constantly maintain what has been pointed out many 

 times before, that the under-layer originates from or gets its character from the 

 easterly running branch of the Irminger Current. The state of matters in section XXI 

 furnish a new proof of the correctness of this assumption. 



