70 



TEMPERATURE. 



Thi Cn'ite of Warm D iijs In the Absence of Insolalion and of the Excess of Temperature 

 at 4 a.m. — Wo, have now shown that, the former of these eft'ects is real in McMurdo Sound, 

 which is the only station at a sutRciently high latitude to allow of the effect being visible, 

 while the latter effect has been shown by all tests to be a real factor in McMurdo Sound 

 and to have been present at the Gauss station and Snow Hill. It is not shown in the onlv 

 observations that we have from Cape Adare (see page 73 below). I am not at pr-sent able 

 to offer any explanation of either of the effects. The only glimmer of light comes from the 

 observations made on the Fram voyage in north polar regions, which will now be discussed, 

 but up to the present this has not led towards a physical explanation. 



Daili/ Temperntarc Variation in North Polar Region.'' from the Records of the 'Fram.' — During 

 the voyage of the Fram which lasted from July 1893 to August 1896, the sun was below 

 the horizon during 12 months. From the observations Mohn deduces the daily variation of 



410 



-10 



(2) 



+to 



+10 



.Cloud 10 



All Obs. 



Cloud O 



+10 



-10 



Wind > 4-5 m.p.s 



+»0 



-10 



hours 2 



ID 



12 



14 



16 



18 



20 22 



24 



Fig. 26. Daily variation of temperature during the dark months. Frani Drift. 



temperature during these dark months .shown in curve 1 of figure 26. It will be .seen that it 

 is totally different from the corresponding curve for McMurdo Sound shown as curve 1 of 

 figure 24j page 67. 



