HYDROGRAPHY. j^ 



the isohalines of the ice-water have a very complicated form. Still it seems to be a rule that there 

 is a layer near the surface of the cold ice-water — most frequently at a depth of 20 — 30 fathoms 

 (38 — 57 metres) — with a pretty high degree of salinity, but its origin cannot be due to Atlantic 

 water, as it has not a corresponding high temperature. Owing to this, it would be an absurd idea 

 to suppose that the Atlantic-water which is cooled in northern latitudes, should penetrate into the 

 ice-water itself, when as we know, it is making its way underneath this latter and forming the under- 

 layer of it. 



The presence of the salt and cold water in the ice-water can more easily be accounted for, if 

 we make the assumption that the high degree of salinity is due to salt, which is eliminated 

 when sea- water is freezing to ice. The lower surface of the ice is always very rough on 

 account of the frequent screwings of the ice, and in the cavities of this rugged surface, water will 

 accumulate successively as the freezing and the elimination of salt is taking place, and this water 

 will be in possession of the qualities: a high degree of salinity and low temperatures. This water is 

 to all appearances led along with the ice, adhering to it in the cavities of its rough lower surface, 

 and getting its place underneath the stratum of water that is formed when the ice is melting, while 

 underneath another layer will be found, originating from former melting of ice. 



The correctness of this supposition may be corroborated by examination of the ratio between 

 the amounts of chlorine and sulphuric acid found in the sea-water. Professor Pettersson writes on the 

 basis of his analyses (»Vega-Expeditionens veteuskapliga Iakttagelser» Bd. II, Stockholm 1883, or «On 

 the properties of water and ice by Otto Pctterssom*, page 305), that the ice is getting richer in sulphates 

 by freezing, while the eliminated brine is getting richer in chlorine*, and that this elimination is con- 

 tinued even after the freezing. If the above assumptions are correct we may expect to find a minimum 



SO 

 of the ratio - j- in the cold salt layer of water, and it will be seen from the following table that this 



is the case at a depth of 20 fathoms (38 metres), in so far as two of the stations 101 and 118 are 



concerned. 



The cold and salt stratum of water which is lying inside the ice-water, is in general heavier 

 than the ice-water lying below it. Consequently the equilibrium is unsteady, and the salt water must 

 try to move downwards towards the under-layer. According to this, it seems to be justifiable to come 

 to the conclusion that when the salt water-layer is found in the ice-water, it cannot have been long 

 time ago that the salt water must have been subject to freezing. 



The observations are, as already said, too few to enable us to prove the presence of this layer 

 of water in all cases, but it seems to be least prominent at the southernmost stations in the ice-water. 

 This agrees very well with the fact of a long time having elapsed since the water at these stations 

 was subject to freezing in northern latitudes. It ought to be noticed that the cold and salt stratum 

 of water is found to be as much expanded at the eastern as at the western stations in the ice-water. 

 This state of matters can hardly be put in connection with a rotation in the ice-water itself, so that 

 the western part of this latter was moving in a southerly direction in order to be turned off in a 

 northerly direction a little more to the eastward; for if this be the case, we might expect to find the salt 

 water-layer less prominent in the most easterly stations of the ice-water. The uniform di- 

 stribution of the salt layer of water in the whole of the layer of ice-water, 



The Ingolf-Expedition. I. 2. 10 



