THE HEART OF THE ANTARCTIC 



Additional Notes by JAMES MURRAY 



The sun, prime source of all the optical phenomena 

 referred to, was seen for the last time before the long 

 winter night on April 27, 1908. One-third of its disc was 

 above the horizon at noon. It was again seen for the first 

 time on August 17, 1908. The entire disc was above the 

 horizon, and the bottom edge one quarter of the diameter 

 from the horizon, so that it could probably have been 

 seen a day or so earlier if the weather had been clear. 

 The long night was therefore of 111 days (or less) . It is 

 supposed that the night at latitude 77° 30' considered 

 astronomically, should be several days longer, and that the 

 sun was seen later and earlier on account of refraction. 



The limits of the long day could not be so readily 

 determined (by observation) as the sun went behind the 

 mountains. The first year we had only a small part of 

 the long day, and we supposed that the sun began to set 

 on February 22, the day the Nimrod left us. The second 

 year we experienced the entire long day, from about 

 October 17 to about February 22. 



There was perpetual daylight on each side of the long 

 day for several weeks, and similarly the long night was 

 tempered by very, good twilight during the day for some 

 weeks at the beginning and end. 



Some of the most striking optical phenomena, as the 

 earth shadows, iridescent clouds, &c., were only exhibited 

 during the short periods when the sun rose and set each 

 day. Others, like the prismatic sunrises and sunsets, con- 

 tinued long into the night. 



In addition to the optical effects familiar in polar 

 regions, such as mock suns and moons, halos and crosses, 

 there were observed a number of optical phenomena which 

 are not so well kno^Ti. 



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