108 FRIDTJOF NANSEN. M.-N. KI. 
ought to have been found near to the Siberian Coast. But the real state 
of things is the exact opposite, as is proved by the observations made 
during that expedition. Over the continental shelf north of Siberia the 
ice is comparatively thin; there is much open water during the summer 
and autumn, whilst the greatest quantity of ice as well as the thickest 
ice-floes are formed over the deep North Polar Basin. There is also 
much more melting of ice going on during the summer in the shallow 
sea north of Siberia, than there is over the deep Basin farther north. 
Prof. Pettersson has two theories about the origin of bottom- 
water of the Norwegian Sea. On pp. 318—319, he assumes that the 
cold heavy water observed at Amundsen's Stations (and at Ryders Sta- 
tions) comes from the North Polar Basin, forms "the deeper layers” of 
the East Greenland Polar Current and sinks ‘to the bottom of the Nor- 
wegian Sea”. It was pointed out above that this theory is impossible, 
because no such water comes from the North Polar Basin with the East 
Greenland Polar Current, the deeper layers of which have no temperatures 
and no salinities similar to those of the cold bottom-water at Amund- 
sen’s Stations. 
On p. 329 of the same paper Prof. Pettersson says that he has 
calculated that part of the Atlantic under-current which mixes with the 
ice-water to be one-eighteenth, while the remaining seventeen-eighteenths 
become cooled from contact with the ice and sink to the bottom, there to 
form the great bottom layer of cold water of only —1:0 to —1°4° C.” 
On the one hand Pettersson here repeats a mistake which the writer 
has already pointed out on several previous occasion. He like several 
other authors obviously still has the misconception that the upper layers 
of diluted cold water of the East Greenland Polar Current are due to 
the melting of ice, whilst the observations during the “Fram” Expedition 
have proved that the whole North Polar Basin is covered by a similar 
layer about 200 metres thick, on the surface of which the polar ice is 
formed. The East Greenland Polar Current is formed chiefly of the 
same waters from the North Polar Basin, having very similar salinities. 
A calculation like that of Pettersson’s is therefore quite fallacious. 
On the other hand Pettersson seems unaware that nowhere in the 
regions mentioned by him does the “Atlantic under-current”, come into 
contact with the Polar ice, from which it is separated by the layer of 
diluted Polar water. This was fully mentioned above. But if in spite 
of all, it be assumed that cold bottom-water might be formed in this 
way by the melting of the ice, such water must be formed chiefly during 
the summer, while the melting of the ice is going on, and it must be 
