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of warm air ; but it may be easily accounted for by supposing that 

 the form of the coast enables the warmth-producing wind to act at 

 a special advantage in breaking up or driving away the ice, and 

 liberating the heat of the waters. 



These extraordinary fluctuations of temperature appear to be com- 

 mon to the whole of the Arctic regions. Sir John Richardson, in 

 his recent work on the Polar regions, states that " in Arctic America 

 the phenomenon of warm winds (teplot weter of Wrangell) also 

 occurs, and makes the month in which they happen, whether Decem- 

 ber, January, or February, warmer than the other two. The same 

 warm wind was probably the cause of the rain which the Russian 

 sailors observed in Spitzbergen in the month of January." 



Rain implies a temperature several degrees above + 28, which is 

 the temperature of the stratum of sea-water immediately below the 

 ice. But we know that in the Polar regions the temperature of the 

 sea increases in descending, until a stratum is reached of the invariable 

 temperature of +39; and we may suppose that in these storms the 

 warmer water of the deeper strata is brought to the surface, and 

 warms the air sufficiently to admit of rain. We know that powerful 

 winds are able to produce temporary local currents, and it is easy to 

 see that such a current, when produced in a limited space free of ice, 

 will give rise to this kind of vertical circulation, or interchange be- 

 tween strata of different depths. 



Such storms as these must be eminently favourable to the produc- 

 tion of rain ; for the air that becomes warmed by contact with the 

 comparatively warm water will, of course, take up watery vapour, 

 and when it comes into contact with other masses of air that retain 

 their usual intense cold, the vapour will be rapidly condensed ; so 

 that we cannot wonder at heavy rains being a general concomitant of 

 these storms. 



Wrangell, in the passages I have quoted, says the warm wind in 

 Siberia is preceded by a fall of the barometer. Dr. Kane, on the 

 contrary, noticed a rise before the storm above described ; it stood at 

 "the extraordinary height of 30'85." I cannot suggest any expla- 

 nation of these facts. 



I believe I have now stated the true cause of what is certainly a 

 very remarkable phenomenon fluctuations of temperature of enor- 

 mous magnitude, occurring in a very short time, and in the absence 

 of the sun. 



