236 Dr. A. Woeikof's Examination of 



In summer the winds in Eastern Asia are S.E., and bring 

 clouds and rain far inland. Owing to the high temperature 

 of the continent and of the surrounding seas, rain and not 

 snow falls even at great heights, for example, up to 15,000 feet 

 in the mountains of Kansu in Western China (37° N.). Thus 

 the heavy rains of summer are not favourable to an accumu- 

 lation of snow, but, on the contrary, assist in melting the 

 small quantity which may remain on the ground. 



During a high excentricity and winter in aphelion the tem- 

 perature must be higher in summer, and this would cause a 

 lower pressure on the plateaux in the interior of Asia. This 

 would increase the difference of pressure between the ocean 

 and the interior of the continent, and give a greater impetus 

 to the moist winds and bring larger quantities of rain, at least 

 where the air is ascending. Such conditions would then 

 favour the melting of snow to a greater height than now. At 

 present, in Northern Thibet for example, permanent snow is 

 found at 17,000 feet ; then it would disappear perhaps even 

 to 20,000 feet. 



The climatic conditions of Asia show us, so to speak, the 

 normal reactions between continent and ocean. Everywhere 

 there is a tendency towards a higher pressure in the interior 

 of continents in winter and on the oceans in summer, and to 

 winds from the first in winter, from the second in summer; 

 that is, there are what Coffin calls monsoon influences. A 

 colder winter in the interior of the continents, with an un- 

 changed temperature on the oceans, would certainly strengthen 

 the winter winds from the interior, and thus bring more cold 

 dry weather than is experienced now, and reduce the precipi- 

 tation in winter. Such conditions are certainly not favourable 

 to a greater accumulation of snow than prevails now. The 

 Ural Mountains have, as well as those of Norway, prevailing 

 W. winds and a much colder winter ; but, on account of the 

 smaller snowfall, no permanent snow and no glaciers, while 

 the W. side of the Scandinavian mountains has enormous 

 glaciers. If a high excentricity with winter in aphelion can 

 have a considerable influence on climates, it would give to 

 Western Europe colder winters with a greater proportion of 

 dry east winds, and warmer summers, both conditions un- 

 favourable to glaciation. 



It has long seemed to me that those who have expressed an 

 opinion on the favourable influence of winter in aphelion on 

 glaciation, from Adhemar to Dr. Croll and his followers, have 

 been influenced by the present difference of the northern and 

 southern hemispheres. The glaciation is far more prevalent in 

 the latter, and this has been ascribed to winter in aphelion on the 



