Depth. 

 metres 



10 



20 



30 



40 



60 



80 

 120 

 200 



10th July 

 Salinity. 



34.22 %o 



34.22 



34.55 



34.87 



34.94 



35.03 



35.03 



35.19 

 35.38 



30th September 



Temperature. 

 11.1 

 10.42 



7.75 



6. 



5.05 



4.52" 



4.6o 



4.9 



5.3 



Salinity. 



32.10 % 



32.45 



32.69 



32.75 



33.81 



33.94 



33.94 

 34.53 



Temperature. 

 9.45 

 9.6 

 9.8 

 9.5 



10. 

 10. 

 7.8 



In comparing these two tables it will be seen that 



1. The 35 curve which, in July, was 50 m. below the surface 

 must be sought for in September at depths exceeding 120 m., 

 the 34.5 % curve was, in July, at a depth of 20 m., but in 

 September was found at a depth of 120 m. 



2. The Surface Salinity decreased from 34.2 to 32.1 % . 



3. The Surface Temperature sank from 11 in July, to 972 in 

 September, but, as a set off, the temperature down in the 

 deep rose considerably; for instance from 4.6 at a depth of 

 80 m., to 10. 



These conditions remind one greatly of those which have 

 been shewn to exist on PI. 5, Figs. 3 and 4, in respect to the west 

 coast. The conditions on the banks in the North are, however, 

 still more instructive, because it must be presumed that the trans- 

 placement of the temperature, downwards, is there not so dependent 

 on currents as on the west coast where the Baltic current plays a 

 great part. It was, moreover, very instructive to find that the 

 fresh water played a greater and greater part the further a fjord 

 was entered. 



It thus shews that in the North, simultaneously with the 

 increased thickness of the fresh layers, a period of heavy rain 

 sets in. As the accompanying tables shew, the rainfall increases 

 greatly in September, and from that month, throughout the entire 

 autumn until January or February, a lengthy season of rain occurs. 

 It is an interesting fact that, just at that time, the fresh layers 

 increase in thickness, and that it is in the fjords, where the rain- 

 fall through the agency of the rivers is most perceptible, that the 

 layers chiefly increase. One factor, which also must be regarded 

 as of great weight in respect to these conditions, is the influence 

 of the winds. 



If, in accordance with the annual reports of the Meteorological 

 Institute, one draws curves representing the frequency of the various 

 winds during the various months of the year, it will be seen (as is 

 also shewn in Capt. RUNG'S atlas of the barometrical pressure over 

 the Northern Ocean) that, during summer, westerly winds are the 

 most prevalent along the whole of the north west coast of Norway. 

 These must, during the summer, contribute to force the Atlantic 

 waters in towards the land. On the other hand, during the aut- 

 umn and winter the direction of the wind is, to quite a paramount 

 extent, south easterly, interrupted, however, occasionally, by westerly 

 gales. The south easterly winds thus drive the water out of the 

 fjords to the banks, and the gales must, on the whole, mix up the 

 bodies of water, and that to a great depth. 



That such a mixture must take place to a very great extent 

 is clear, it appears to us, from the salinity becoming steadily less 

 as the autumn advances. The homogeneousness is greatest in 

 January and February, as both the atmosphere and the fresh water 

 from the rivers cool, especially, the upper layers. 



Fig. 1 . Kainfall in millimetres, during the various months of the year, at 



Svolvfer and Floro. 



It is known that layers of water of different specific gravities 

 are not at all inclined to combine. Thus the Baltic current, 

 during the summer, floats upon the salter layers beneath, without 

 its being possible to observe any admixture. 



These conditions do not, at all events, exist in the North 

 during the autumn, or in western Norway. This is seen, for in- 

 stance, when the density of the water during the winter at various 

 depths is calculated. The density of the Ocean water during the 

 various months of the year may be calculated from Figs. 5 and 6. 

 If one takes an example from February, one obtains the 

 following figures : 



metres 1.02666 



10 2666 



20 2664 



30 2670 



40 2679 



50 2681 



60 2679 



70 2678 



80 2670 



90 2681 



100 2686 



110 2682 



120 2683 



130 2689 



140 2689 



150 2688 



160 2688 



170 2689 



180 2691 



190 2696 



200 2697 



210 t 2700 



220 ' 5705 



2,50 2710 



240 2715 



250 1.02720 



