10 



the winter." That the surface temperature in winter, at harbours 

 or close to land generally, is lower than further out, has constantly 

 been confirmed by experience. Even though the land be a com- 

 paratively small island, it has proved to be the case. Thus on 

 March 13th 1896 the surface temperature in the Rdstnes-Vaag 

 (Vert) was 2.2 C., while about 3 miles off land I measured 3.4 C. 

 As a rale, the saltness too is least near the land. I will give a 

 few instances chosen at random: 



February 25th 1897. 



Liland harbour, Ofoten-fjord . t 0.8 C., s. 33.06 %o 



Out at sea, off Liland 1.6 - - 33.30 - 



At mouth of Ofoten-fjord - 2.4 - - 33.30 - 



March 18th 19th 1897. 

 Section across the Vest-fjord (Groto Svolvser). 



At Gr6to t. 1.2 C., s. 33.73 %o 



Six miles off Gr6t6 - 2.7 - - 33.91 - 



In the middle of the Vest-fjord - 2.8 - - 33.96 - 



Hola, near Svolvser - 2.2 - - 33.84 - 



Thus it seems to be a rule that in winter temperature as well 

 as saltness is highest along the middle of the fjord, a lowering 

 taking place to either side. I have before mentioned that the water 

 layers on the outer banks show a greater homogenousness in tempe- 

 rature and saltness than in the fjords and on the inner banks. 

 Thus it has also been shown that in the harbours of the outer 

 side of Vesteraalen the water is exactly of the same saltness as 

 further out, while however the temperature is somewhat lower on 

 account of the coldness of the land. 



In a paper in the transactions of the Kristiania Videnskabs- 

 selskab for 1873. professor MOHN has discussed the effect of cur- 

 rents on the temperatures of the water and the air. 



Mr. MOHN here emphasizes as the result of his own observa- 

 tions that the surface temperature in the streaming water of narrow 

 channels is in summer lower than at neighbouring places where 

 the waters are wider. It is also suggested that in winter the sur- 

 face of streaming water is somewhat warmer than in places where 

 the water is at rest, but that the difference is likely to be small. 

 The author alleges many illustrating instances that the difference 

 mentioned can be quite considerable, even as much as 3 C. The 

 phenomenon is, according to Mr. MOHN. explained thereby that the 

 colder water, on account of the streaming motion, is drawn up to 

 the surface. 



During my expedition in 1896, I made a few observations 

 supporting Mr. MOH.N'S theory about the winter temperature in 

 streams. Feb. 14th 1896 I measured off Kvarven near Bergen 

 3 in the surface, in the VatlestrSm south of Bergen 5.4, further 

 down in Vatlestrdmmen 5, and in the Kors-fjord on the same 

 day 4.5 C. In the well known Mosken-strom that runs between 

 Lofotodden and Vser6, I have also perceived a small difference 

 of temperature between the surface of the stream and the sur- 

 rounding open sea (see hydr. tables no. 202 205.). With a 

 little increase of temperature also follows a corresponding small 

 increase of saltness. It is obvious that the increase of tempera- 

 ture in streams in winter is rather slight, just because the increase 

 in temperature is quite trifling in the upper water layers. 



The local conditions of the Lofoten streams are of no small 

 importance during the fishing, as a strong current is a hindrance 

 to the use of the fishing tackle. The current caused by the tiile 

 is very much differing in strength, and there are great irregulari- 

 ties in its direction. It often happens that the direction of the 

 current near the Lofoten islands is quite opposite to what it is 

 farther up the Vest-fjord. Tims for instance on March 26th 1896 

 I observed, 8 miles off Reine, a sharp boundary between a south- 

 westerly current and an easterly one, the former of which was 

 nearest to Lofoten. That this was no mere chance is proved by 

 some statements I received from captain A. SORENSEN of observations 

 taken at Reine in April of the same year: 

 April 6th and 7th at 10 a.m. the current ran westwards about 8 



miles off Reine, wind being S\V. 

 April 8th, 12 noon, wind N\V, near Lofoten an easterly current, 



8 miles off Reine a westerly current. 

 April 9th, at 2 p.m., wind SE, near Lofoten easterly current. 6 



miles off Reine westerly current. 

 April 10th, 2 p.m., wind SW, current conditions the same as on 



the previous day at 2 p.m. 

 April llth, 4p.m., wind NE, the current nearest Lofoten easterly, 



and about 8 miles off it was westerly. 



This at any rate shows that the direction of the current close 

 to the islands and farther up the Vest-fjord may differ for several 

 consecutive days. It is most likely that this is the rule. My 

 measurements on March 26th 1896 showed different surface tempera- 

 tures at the two sides of the boundary of the currents, the tempera- 

 ture of the east-running current being 3.6, and of the west- 

 running one 3.2 C. In saltness too there was a small difference 

 (see hydr. tables, no. 219, 220). 



I cannot well leave the present chapter without once more 

 mentioning the much debated question of the dependence of the 

 fishing upon the temperature of the sea. 



From what has been said above it will have appeared that 

 the temperature measurements of the first years seemed to lead to 

 the conclusion that the use of the thermometer might be of practical 

 service to the fisherman. It is however quite a common thing that 

 at first too much importance is attached to the bearing of scientific 

 discoveries upon practical life. People will see assistance and impro- 

 vement where such are really not at hand. I therefore think that no 

 great importance can be attached to the few statements we have from 

 fishermen about the help obtained from the thermometer in their 

 work. Nor can it be denied that 5 degrees as the best tempera- 

 ture for fishing has been made doubtful by the investigations of 

 recent years. Mr. GADE, as before mentioned, found that good 

 fishing was carried on in water of 4, 6, 6, 7 C., and I have 

 ascertained that about the middle of March 1897 there was good 

 fishing on the banks from Henningsvser to Balstad in water of 3 

 degrees. In the month of March, when the chief fishing takes 

 place, the thermometer can consequently be of no guidance to the 

 fisherman because the scope is too great (3 7 C.). 



A little cod-fishing I have also seen going on in water of 2 

 degrees (Ostnes-fjord). 



The fishermen state as a common experience that the cod at 

 the beginning of the season most often keeps to the fjord edge in 



