309 



fourth place of decimals quite uncertain. The remarkable extension 

 of the spectrum of this electric light, both at the red and violet ends, 

 is, however, indisputable. 



VI. "On Great Fluctuations of Temperature in the Arctic 

 Winter." By J. J. MURPHY, Esq. Communicated by 

 Professor W. THOMSON. Received June 7, 1861. 



It might be expected that the climate of the Arctic Regions during 

 winter, in the absence of the sun, must be almost a dead level of 

 intense cold ; but so far is this from being the case, that there is no 

 other place and time where such great and rapid fluctuations of 

 temperature have been observed. 



This phenomenon is thus mentioned in the appendix to Wrangell's 

 account of his expedition to the Siberian coasts of the Polar Sea : 



" Sometimes in the middle of winter a wind from the S.E. by E. 

 causes the temperature to rise suddenly from 24 to + 25, or even 

 + 32: previously to this, the barometer sinks as much as four- 

 tenths of an inch in the course of eight hours. The S.S.E. wind has 

 no particular influence either on the barometer or thermometer." 



In " The Search for Sir John Franklin," published in No. 1 of the 

 ' Cornhill Magazine,' occurs the following notice of the same phe- 

 nomenon. The * Fox ' was beset by vast fields of ice somewhere in 

 Baffin's Bay : 



" December 28. During Divine Service yesterday the wind increased, 

 and towards the afternoon we had a gale from the north-westward, 

 attended with an unusual rise of temperature : today the gale con- 

 tinues, with a warm wind from the N.N.W. 



" The Danish settlers at Upernavik, in North Greenland, are at 

 times startled by a similar sudden rise of temperature. During the 



VOL. XI. Z 



