24 



BJØRN HELLAND-HANSEN AND FRIDTJOF NANSEN. 



M.-N. Kl. 



But as the surface-layers are on the whole very variable, especially 

 in these regions, where there is so much lighter surface-water, and as their 

 temperatures vary much with the season, it may be advisable to leave 

 them out in our comparison. For the sake of convenience we have there- 

 fore chosen the temperatures at 100, 200, 300, and 400 metres. The means 

 of these temperatures may give fairly trustworthy values for the mean 

 temperature of the whole volume of water between 50 and 450 metres of 

 depth. The results are given in the second part of our table. There is, 

 however, no great difference between them and the former ones. 



The increase of temperature between June and September was very 

 much greater at Stat. 3 (+ i-i?" C.) than at Stat. 4 (-f 0.21" C). This 

 proves the necessity of comparing the observations at as many stations as 

 possible in order to get a fairly trustworthy estimate of the rate of the 

 heating of the waters of the current during the summer. The increase of 

 temperature at Stat. 3 was from 3.01° C. on June 25th t0 4.i8°C. on Sep- 

 tember 7th; /. e. i.ry*^ C. in 74 days, or about 0.16" C. in 10 days. 



If we take the means of Stats. 3 and 4 combined, the increase of 

 temperature would be from 3.08^ C. on June 25th, to 3.72** C. on Sep- 

 tember 7th, /. e. an increase of 0.64'^ C. in 74 days, or about 0.09" C. in 

 10 days. 



The corresponding increase of temperature was, at Stat. 29, from 

 2.71° C. on July 22nd, to 3.31" C. on September 6th; /. c. an increase of 

 0.60'^ C. in 46 days, or about 0.13" C. in 10 days. 



