Vol. 57.] CLIMATE OF THE PLEISTOCENE EPOCH. 435 



Greenland, it may stretch towards the north-east, as shown in the 

 January chart (fig. 17, p. 450). When, on the contrary, it shifts to 

 the west, it often points north -westw^ard. This happened constantly, 

 for example, during the months of September and October, 1881, so 

 that the statistical diagrams for those months show a low-pressure 

 system with a distinct south-easterly and north-westerly alignment, 

 accompanied by the advance of the Asiatic anticyclone towards 

 Scandinavia and the North Sea (see fig. 10, p. 436). 



If such a state of things may prevail for a space of two months 

 at present, when generally the conditions are favourable to a 

 contrary arrangement, there does not seem anj^ insuperable difficulty 

 in supposing that, under the altogether different and more permanent 

 circumstances set up by the existence of the great ice-sheets, it 

 might have persisted during a lengthened period. 



In attempting to restore the probable distribution of areas of 

 high and low barometric pressure during the Pleistocene Epoch, 

 I found it nearly impossible to do so in such a way as to fulfil 

 what seemed to me to be the necessary meteorological conditions, on 

 the hypothesis that the maximum glaciation of North America and 

 Europe took place at the same time. No such difficulty arose, how- 

 •ever, when I adopted the view that the most important glacial and 

 interglacial periods may have been more or less alternate in the eastern 

 and western continents. On my mentioning the matter to Mr. W. N. 

 Shaw, he was kind enough to call my attention to an instructive case 

 of anomalous climate which occurred during the winter of 1898-99. 

 Erom December to Eebruary in those years the weather on the 

 western side of the Atlanrtic was persistently and abnormally severe, 

 temperatures of from —40° to —60° Fahr. having then been com- 

 monly registered in dififerent parts of North America. The excessive 

 cold extended in February as far south as the mouth of the Missis- 

 sippi : the thermometer falling there to 10° Fahr., the swiftly-flowing 

 rivers of the Southern States were frozen over, and ice was carried 

 out into the Gulf of Mexico. On February 11th, the barometer fell 

 to nearly 28*5 inches in the Atlantic, rising at the same time in 

 Canada to 31*42 inches. For some weeks gales of great violence 

 occurred almost daily in the Atlantic, and in different parts of the 

 North American continent, a wind-velocity of 72 miles an hour 

 being noted in Massachusetts; while in New York Harbour, during 

 a blizzard, one of the great ocean liners, the Germanic^ sank at 

 her moorings under the weight of the snow and ice which covered 

 her deck and sides. Exceptionally mild weather prevailed at the 

 same period in Western Europe as far east as the Ural Mountains, 

 there having been an entire absence of cold weather in January 

 over Great Britain. Maximum temperatures of 70°- 5 Fahr. were 

 recorded in February at Liege (131°-5 above the American minimum 

 of the preceding night), 69° in Paris, and 6G° in London. The 

 wave of warm air affected in a similar way the Alpine regions : at 

 Davos Platz, in the South-east of Switzerland, 5.000 feet, above sea- 

 level, a maximum of 63° Fahr. was reached, the highest previously 



