THE HEART OF THE ANTARCTIC 



spoken of as disjointed curtains. Some curtains were not 

 folded at all, but stretched across the sky as simple bands, 

 which were sometimes called arches. An entirely different 

 kind of arch could, however, be distinguished. 



Arch Aurora. — This consists of a series of bright 

 patches, arranged in a large arc or circle, and of long 

 tapering beams going upw^ards from each patch. Exam- 

 ined closely there is a sharp distinction between the narrow 



Curtain Band Circling Erebus, May 26 



tapering beam, and the brighter expanded portion. The 

 arch in its typical form is much less common than the cur- 

 tain. The rays are often seen coming from beyond the 

 horizon, or from beliind hills, while the basal arc is hidden. 

 Similar beams often rise far apart, but still apparently 

 radiating from a centre. Others are unconnected, and 

 incline at various angles. These form a transition to the 

 searchlight type. 



388' 



