236 



NATURE 



[August 25, 1910 



dividing into a large and a small mass. At this stage 

 everything turns on the question of which is stable of 

 the series of figures through this point of bifurcation, 

 the Jacobian ellipsoids on the main road, or the pear- 

 shaped figures on the cross-road. Sir George Darwin 

 believes he has proved the pear-shaped figures to be 

 stable, but M. Liapounoff challenges this, and, as the 

 result of an independent investigation, thinks these 

 figures are unstable. Each investigator has again 

 verified his own calculations, and Sir George Darwin 

 has applied various checks to his work which afford 

 some evidence, although not proof, that his original 

 conclusion was accurate. 



Here the problem at present stands, at a deadlock. 

 Short of discovering a serious error in one or other of 

 the two investigations, the only explanation of the 

 discrepancy seems to lie in the rejection of certain 

 remote, and apparently very small, terms by Darwin. 

 These might possibly be found to turn the balance, 

 but it is almost inconceivable that they should. 



Whatever the outcome may be, the present volume 

 stands as a record of the amount of patient labour 

 and degree of mathematical and scientific skill brought 

 by one worker to the examination of one theory of 

 cosmogony. Before the scientific world permits other 

 theories to take their place by the side of this one, it 

 will do well to ask whether the truth of these other 

 theories has been investigated with a degree of 

 patience, skill, and power at all comparable with what 

 is shown here. 



THE POLAR WORLD AND GLACUL 

 GEOLOGY. 

 Die Polarwdt tiiid ihre Nachbarldiidcr. By O. 

 Nordenskjold. Pp. vii + 220; 77 figures. (Leipzig: 

 B. G. Teubner, 1909.) Price 8 marks. 



DR. OTTO NORDENSKJOLD is especially well 

 qualified for a comparison of the .Arctic and 

 Antarctic regions, which he has personally explored in 

 Greenland, Iceland, Spitsbergen, Alaska, Patagonia, 

 and during his leadership of the Swedish Antarctic 

 E.xpedition. He has now issued a short work on the 

 polar world, in which he has given a general geo- 

 graphical description of the Arctic and Antarctic lands, 

 and reference to the interesting problems connected 

 with their geographical structure, inhabitants, and 

 glacial geology. The book is based on a series of 

 popular lectures and is issued without references. It is 

 illustrated by seventy-six views, mostly taken by the 

 author or on expeditions of which he was a member. 

 The only map is a sketch of part of southern Pata- 

 gonia. 



The book owes its main value to its statement of 

 the author's conclusions relating to various geograph- 

 ical and geological problems in which he is especially 

 interested. Greenland is naturally described first, as 

 it is the typical polar country, it being the most 

 accessible and best-known land still covered with an 

 ice-sheet. The author rejects Nansen's view of the 

 nature of its ice gradient, and says that the problem 

 of the Greenland inland ice was not solved by his 

 expedition, which crossed the country at its narrow 

 NO. 2130, VOL. 84] 



southern end, where the glacial conditions are not 

 fully representative. 



Di . Nordenskjold describes the fiord system of 

 north-eastern Greenland, which he considers as the 

 greatest in the world. Its valleys were once occupied 

 by glaciers during a former greater extension of the 

 Greenland ice cap ; unless they had been filled with 

 ice he would refuse them the name of fiords. He 

 admits that part of Greenland has never been covered 

 by ice, though he remarks that the evidence for this 

 conclusion must be treated with caution. He briefly 

 discusses the Eskimo, the most interesting of polar 

 people. He accepts their Asiatic origin as appar- 

 ently beyond question ; the problem regarding them 

 which he regards as still unsolved is the home of 

 their present culture. Hamberg has suggested that 

 the race developed its special characters in Alaska, but 

 Dr. Nordenskjold doubts this conclusion, as he thinks 

 it probable that, if so, they would have spread west- 

 ward into Asia, where but few of them occur, as 

 well as eastward. He thinks their last home was 

 probably within the centre of their present area of 

 distribution, and not on its margin. 



After describing Iceland and Jan Mayen, Dr. 

 Nordenskjold turns with enthusiasm to Spitsbergen, 

 which he describes as the classical land of Arctic 

 research. It is at present of little economic value, as 

 it has been abandoned alike by whale, walrus, and 

 seal hunters. Since 1905 attempts have been made to 

 mine its coal, but Dr. Nordenskjold regards the suc- 

 cess of these attempts as very doubtful ; and he thinks 

 the country will be mainly of value as a tourist resort. 

 He raises the question of the ownership of Spitsbergen, 

 refers to the respective titles to its possession by 

 Holland, Great Britain, Norway, Sweden, and Russia. 

 A conference between the last States is now discussing 

 the political status of the archipelago. 



Dr. Nordenskjold also describes the .-Arctic areas 

 of America and Siberia, and gives a brief summary 

 of recent work on the Antarctic, with an account of 

 southern Patagonia, and a reference to Tasmania and 

 New Zealand. He directs attention to the evidence of 

 the former greater extension of ice in nearly all polar 

 and subpolar countries, and he recurs frequently 

 throughout the lectures to glacial problems. ,\s the 

 cause of the former glacier extension he regards 

 Arrhenius's theory of refrigeration of the earth owing 

 to the diminution in the carbonic dioxide in the atmo- 

 sphere as inherently probable; he admits, however, that 

 the chief different glacial centres of North .-\merica and 

 elsewhere are not contemporaneous, that there was 

 no equivalent glaciation of Siberia, and that there is 

 no evidence of a former existence of ice in some parts 

 of Alaska as in the Yukon district. The oft-made 

 suggestion that the ice developed in localities which 

 had a moist climate and heavy snowfall he rejects 

 from the evidence of Kerguelen, where, in spite of 

 these conditions, there is much ice-free land. Ker- 

 guelen, however, is only in the latitude of Paris. 



Consideration of the westward extension of the Scan- 

 dinavian ice-sheet leads him to consider the general 

 belief that the Scandinavian ice filled the North 

 Sea and deflected the local glaciers northward. 



