30 JOHAN MJORT. M.-N. Kl. 



we shall subsequently see, this is mainly different when the fresher 

 layers (as was the case, for instance, in 1895) reach the Spring Herring 

 District in February or March. The Baltic Current is then greatly 

 mixed with ice water, and cold water from the rivers. In those months 

 the temperature of the current, therefore, varies from 2 ° to — i ". In 

 the month of April, however, the temperature of the air rises, especially 

 in the Baltic regio'ns, and the Baltic waters are, therefore, during April 

 gradually heated to 6° or 6.5 degrees. It will thus be found that the 

 sea, from its surface to a depth of nearly 250 mètres, is of almost a 

 like temperature. Only a little way beneath the surface does a lower 

 temperature appear, therefore a minimum. Although this, in April 1894, 

 was not much colder than the temperature of the surface and that of 

 the deep water, the lowest temperature being 5.8 0, the presence of this 

 minimum is, nevertheless, characteristic in denoting a transitional con- 

 dition, which is, probably, present once each Spring previous to the 

 development of the Summer conditions, when, as mentioned, the tem- 

 perature falls from the surface towards the bottom. This condition 

 will, however, vary somewhat in different years. During some years the 

 Baltic Current advances at an earlier date than during other years. In 

 the first case it would be cold, and colder than the lower lying layers. 

 As Spring wears on the Summer conditions become successively deve- 

 loped through the influence of the warm air from above (and by the 

 conveyance of warmer Baltic Water from the South East), In another 

 year the Baltic Current will only reach the West Coast at a late period 

 (as in 1894), and it will then, in some years, be warmer than the salter 

 layers which it covers. In both instances, however, a minimum will be 

 developed (it must be remembered that the water is warm at the bot- 

 tom), but the differences in the height of the temperature will, possibly, 

 vary considerably in different years. The question must be left to sub- 

 sequent researches. 



Winter, iSgjj. The Surface Chart for February 1895 (E), shows 

 that the Baltic Current had then a considerably greater spread than 

 during the previous year. Whilst in 1894, the current was dammed up 

 in the Cattegat and the Christiania Fjord, in 1895, it w^as met with off 

 Christianssand. We find that its salineness was about 31 pr. 1000, and 

 its temperature i ". Away, seawards, from the coast, the salineness and 

 temperature increases. The samples obtained at intervals of two hours 

 on the steamship route Christianssand — Antwerp, gave the follow- 

 ing" results: — 



