400 KANSAS ACADEMY OF SCIENCE. 



and the longest extension of it (56 miles) is with the wind. How 

 much the wind has to do with modifying the form of the circle of 

 vision I do not know. Ordinarily I would expect the longest diame- 

 ter of this circle to be east and west, in accordance with the valley 

 of the Kaw. 



These observations show that mirage occurs often ; always occurs 

 at night, when the wind is calm, the sky clear, radiation strong, and 

 the temperature falling. It usually disappears as soon as the tem- 

 perature begins to rise in the morning. 



Ordinarily in Kansas, with its lovely skies and transparent air, we 

 do not have to "wait until the mists gang awa'" in order to be able to 

 "see as far as the mune." 



