Septembeb 2, 1910] 



SCIENCE 



311 



denskjold says this is incorrect; that one 

 should remember that the climate is no worse 

 than that of Belgium and that real cold i3 

 never felt, that parrots and magnolias flourish, 

 and that a guanaco skin cloak is really suffi- 

 cient protection for a savage under the cir- 

 cumstances. In many other vrays, also, the 

 natives show that they have adapted them- 

 selves to their environment. Had they been 

 treated as the Eskimos were in Greenland, 

 they would undoubtedly have survived. 



Of sub-antarctic islands. Dr. Nordenskjold 

 does not write from experience. But he calls 

 attention to the fact that Kerguelen Land has 

 the most oceanic climate in the world, in 

 summer about like that of October, in winter 

 about like that of November, in southern 

 Sweden. And he also justly bewails the im- 

 pending extinction there of the sea-elephant. 



Of northern iSTorth America and Siberia, 

 Dr. Nordenskjold says they are quite diilerent 

 in their nature from true polar lands, and the 

 underlying cause is that they are continental 

 masses and therefore have continental cli- 

 mates. Though the winters are very cold, the 

 summers are hot, and these melt the snows 

 and restrict the glaciers to mountain regions. 



The northern American archipelago, Baffin 

 Land, Grant Land, etc., has a semi-oceanic 

 climate, and is far north. It is therefore 

 covered with ice in spots, but there is not a 

 true ice cap. There was unquestionably a 

 time when most of arctic North America was 

 glaciated, nevertheless, there are spots where 

 this does not seem to have been the case. For 

 instance, in some parts of the Yukon Valley 

 the shape of the hills, the absence of moraines, 

 and the weathered slopes of the ranges would 

 seem to prove that these places could never 

 have been overlain by glaciers. The surface 

 gold is also a proof, for had a glacier spread 

 over the valley, the gold would have been 

 swept away. 



Dr. Nordenskjold does not know Siberia at 

 first hand. He calls attention to the fact that 

 it is even more continental than North Amer- 

 ica, and that it has the most continental cli- 

 mate in the world, with very cold winters and 

 hot summers. The latter, and also probably 

 the lack of great mountain ranges, keep 



Siberia free from an ice cap. Large areas of 

 the ground, however, are frozen solid, and 

 these have yielded mammoths in a state of 

 such good preservation, that we can be certain 

 they were really a polar animal. When the 

 hot summers begin, they loosen first the 

 southern headwaters of the streams, causing 

 fearful floods and ice gorges as the water piles 

 up against the still frozen northerly sections 

 of the mighty rivers. Dr. Nordenskjold makes 

 some comparisons between the Eskimos and 

 the Siberian natives, showing how these also 

 have adapted themselves to their environment. 



Scandinavia is really a high plateau and 

 resembles Labrador. It has an oceanic cli- 

 mate, but with relatively warm summers. 

 Formerly northern Europe was entirely gla- 

 ciated. Then one stream of ice from Scandi- 

 navia and one from Scotland poured into the 

 North Sea and this may have formed sheK-ice 

 not unlike the Great Ice Barrier. The sum- 

 mer climate must at that time have been 

 under 0° C. There must have been cold and 

 mild periods, and sometimes the climate must 

 have been not unlike that of Patagonia, while 

 at other times Scandinavia, with its sharp 

 rock towers standing outside in the ocean, 

 must have resembled the South Shetlands. 



At present continental ice caps are found 

 in Greenland and in Antarctica. Ice caps 

 also cover some islands. In the glacial period, 

 true ice caps extended over northern Europe 

 and most of North America, but not over 

 Siberia or Patagonia, where, however, there 

 was heavy glaciation. There is nothing to 

 show that the glacial period was not simul- 

 taneous in both hemispheres and the climate 

 was certainly colder than now. For wherever 

 there are ice caps to-day, as in Greenland and 

 Franz Josef Land, there are arctic climates: 

 with a maximum for the whole year of under 

 — 5° C, and with very cold summers. The 

 glacial period could not have taken place if 

 the climate had been mild and damp, as can 

 be judged by Kerguelen Land. It can not be 

 proved as yet what caused the lowering of the 

 temperature, but the hypothesis of Arrhenius, 

 that there was less carbonic acid (kohlensdure- 

 geJialtes) in the air, has some probability. 

 Ed\vin S^vift Balch 



