58 LEWIS : 



latter images were also missing, and in this particular spec- 

 tacle could not have occurred even had atmospheric condi- 

 tions been perfect for their formation, since the outer halo had 

 a radius so large that it would have passed entirely outside of 

 the parhelic circle. A third image may also be observed, in 

 some cases, in the more brilliant displays. It is known as the 

 anthelion, and derives its name from the Greek on account of 

 the position it occupies on the outer halo opposite to the sun. 

 All of these images may appear as glowing spots, but some 

 noted writers on these subjects describe them as having flam- 

 ing tails and state that they are most clearly visible when the 

 sun is near the horizon. To account for the presence of the 

 mock suns would appear to be a simple matter if the anthe- 

 lion image could be ignored and eliminated from the discus- 

 sion, for then they could be explained as the result of one 

 band of light crossing another band, causing at the points of 

 intersection, as it were, a double thickness of light that would 

 naturally and necessarily appear as bright spots or high lights. 

 These images are, however, the result of intersecting, or 

 rather focal, points of innumerable rays of light that are 

 reflected through the many shaped ice particles at various 

 angles and those that are reflected from the vertical sides and 

 the bases of different length prisms. 



The failure to see a complete outer halo in Media may be 

 attributed to any one of the following possible causes : — 



(i) A very thin or rare area may have existed in the 

 field or cloud curtain that contained the ice crystals, which 

 was suspended between the sun and the points of observa- 

 tion in the vicinity of the town ; 



(2) There may have been an unusual scarcity of the 

 certain shaped crystals necessary to refract the rays of 

 light the required amount to form a complete circle ; 



(3) The thickening haze or the heavy clouds of the 

 approaching storm may have obscured the rays of the sun 

 to such an extent that they were so greatly diffused or 

 intercepted that they could not penetrate sufficiently to 



