12 
EASTERN ETHIOPIA 
I 
is seen exactly over the spot where the sun is about to 
appear. The extent and intensity of the luminous 
Ill the silence of the library it was amusing to watch a gecko dart 
across tlie ceiling catching flies. The inset shows the lamellae which 
enable it to climb easily and quickly smooth vertical surfaces. 
area vary greatly, and the variations depend very 
much on the condition of the atmosphere. In the 
evening, about an hour after sunset, a similar luminous 
cone appears in the sky at the place where the sun has 
just quitted the horizon. 
