of the Fishery Board for Scotland. 



431 



respective densities found were 1025'62 and 1025*54. This increase of 

 density of the surface water from north to south is evidently due, in part 

 at least, to the upwelling of the bottom water immediately to the north of 

 the Dogger Bank. This upwelling is also clearly indicated by the low 

 temperature of the surface water at Station XLIII. 



Temperature Observations. 



Section I. is a graphical illustration of the distribution of temperature 

 along a section of the North Sea from North Unst eastwards to the coast 

 of Norway. On September 19th and 20th, it will be seen that the 

 temperature of the main bulk of the water lying immediately to the east 

 of the Shetland Islands, lay between 47° and 52° P. (8°*3 C. and 11°-1 C), 

 but as the coast of Norway was approached, the temperature of the upper 

 layer steadily increased, while that of the bottom layer decreased, till at 

 Station XXVIII., off the coast of Norway, the temperature of the water 

 a few fathoms below the surface had risen to 56° F. (13° "3 C), and the 

 temperature at the bottom had fallen to 43° F. (6°*1 C). At the same 

 time the depth of the intermediate layer of water having a temperature of 

 between 47° F. (8°-3 C.) and 52° F. (11°-1 C), diminished from over 

 50 to less than 20 fathoms, notwithstanding the greatly increased depth 

 from surface to bottom. On the other hand, the warmer upper layer 

 and the colder bottom layer both rapidly increased in thickness, till at 

 Station XXVIII. a layer of water over 90 fathoms deep and having a 

 temperature of from 56° to 52° F. (13° '3 C. to 1 1°*1 C), was found over- 

 lying a layer of water nearly 90 fathoms deep, the temperature of which 

 was between 47° and 43° F. (8°*3 C. and 6 0, 1 C), the intervening layer 

 being less than 20 fathoms deep. 



Section II. gives a graphic illustration of the distribution of 

 temperature three weeks later along a section of the North Sea from 

 a point in the Firth of Forth near Kinghorn, passing to the south of the 

 Isle of May and extending 300 miles out to sea towards the Skaw. The 

 first point to be noted with regard to this section is its comparatively 

 slight and uniform depth. Further, as in the section some 200 miles further 

 north, the temperature of the great bulk of water lying to the west, that 

 is, lying off the east coast of Scotland, lay between 47° F. and 50° F. 

 (8°*3 C. and 10° C). Another point of similarity between the two sections 

 is the gradual thinning from west to east of the layer of water having a 

 temperature between 47° F. and 50° F., accompanied by an increase of 

 thickness of the upper and warmer layer, and also of the lower and 

 colder layer. This similarity, however, only extended to a point about 

 180 miles distant from the western side of the southern section, for from 

 this point eastwards the thickness of the upper and warmer layer 

 diminished rapidly from west to east, while that of the intermediate 

 layer increased, until at Station XLII. it reached the surface where the 

 temperature of the upper five fathoms was only 49° F. On the other 

 hand it will be noted that the increase of depth of the colder bottom 

 layer from east to west was unbroken, so that at Station XLII. the 

 temperature of the water from the bottom to within 13 fathoms from the 

 surface, was found to be as low as 42° F. (5° 5 C). At this point, 

 therefore, the warmer layer of water was absent altogether, while a layer 

 of cold water below 43° F. (6°"1 C.) extended from about 10 fathoms 

 below the surface to the bottom. 



How far this represents the normal state of affairs it is impossible to 

 say at present, but this upwelling of cold bottom water to the north of 

 the Dogger Bank appears to occur very frequently. It would be interest- 

 ing to ascertain the exact distribution of temperature along this section 



