92 FRIDTJOF NANSEN. M.-N. Kl. 
in this region, than in any other part of the Norwegian Sea, hitherto 
investigated with modern instruments 1. 
The circulation of the bottom water in the Norwegian Sea cannot 
be described in detail. As was pointed out above, it is chiefly formed 
and sinks towards the bottom during the winter and spring in the regions 
between 73° and 76° N, Lat., and between 4° W. Long. and 4° E. Long. 
From this region it moves along the bottom and spreads out laterally 
producing perhaps several cyclonic movements in the deep strata of the 
Norwegian Sea. During this circulation it is very slowly heated from 
the underlying warmer bottom, and also slightly from the overlying 
warmer water, chiefly by convection. In this manner its temperature 
near the bottom is gradually raised from about —1°3° C. to about —r1'1" C. 
and perhaps —1'o° C. 
It seems hardly probable that the bottom-water flows directly south- 
wards by a single cyclonic movement, from the region of its formation 
along the western slope of the deep basin towards the Færoe-Iceland 
Ridge, thence eastwards along its northern sope, and northwards again 
along the eastern slope op the basin. For if it be assumed that a layer 
of bottom-water, about 500 metres thick, has been heated as much as 
0.1" C., by the subterranean heat of the Earth, on its way from 73° 
N. Lat. to 64° N. Lat., north of the Færoe Islands it means that the 
water has spent perhaps 50 years on this distance, or in other words 
that it has moved with an average velocity of about 0°64 mm. pr. second. 
1 At Ryders Station X a temperature of —1°3° C. was observed at 1830 metres (1000 
fathoms). At his Stat. IX the observations gave —ı'2° C. as being the temperature 
of the bottom-water below 1130 metres (600 fathoms). 
Previous expeditions have on the whole obtained very low temperatures for the 
bottom-waters of the Norwegian Sea. This is, for instance, the case with the Nor- 
wegian North Atlantic Expedition, whose bottom-temperatures seem to be on the whole 
one or two tenths of a degree too low; and in some cases even more, e. g. at Stat. 302, 
where Mohn gives a bottom-temperature of —1°7° C., whilst his Negretti and Zambra 
reversing thermometer gave —1'48? C. which is more probable, although perhaps even 
that is somewhat too low. But Mohn’s numerous bottom-temperatures show a marked 
tendency to sink towards the region of his Stations 302 and 303, and of Amundsen’s 
Stations (see Mohn, of. cit. Pl. XXV). Mohn has, however, had a theory that the 
bottom-temperatures should be especially low below the East Greenland Polar Current, 
and he drew his bottom isotherms accordingly, which has lead to a somewhat misleading 
picture. E. g. bottom-temperatures as low as —ı'"4° and —1'5? C. do certainly not exist 
in the sea between Jan Mayen and Iceland. The bottom-temperature there is about 
—1° C. according to the Ingolf Expedition, and —o’94° C. at Stat. 18 of the "Michael 
Sars” (Aug. 1900) further west, and at Stat. 19 nearer Jan Mayen it was —0'88° C. 
at 1300 metres. Ryder found the temperature near the bottom at his Stations II and 
III (between Iceland and Jan Mayen) to be —1‘o° C., and —r'ı° C. at Stat. IV, at a 
depth of 1830 metres. 
