( 582 ) 

 C. Cloudy and uncloudy 



sky. 



which in a few cases have been slightly altered, I have derived the 

 following list of temperatures for clear weather from kilometer to 

 kilometer. 



Although the adopted values for the temperature of the air above 

 13 kilometer are not very certain, yet the observations indicate that 

 at these heights the temperature decreases slowly with increasing 

 height. The refraction in those higher strata being only a small 

 part of the computed refraction, nearly 1 / 10 , an error in the adopted 

 distribution of temperature will have only a slight influence on my 

 results. 



1 must remark that almost all the observations have been made 

 during the day, generally in the morning. It is evident that the varia- 

 tion of temperature, especially near the surface of the earth, is not 

 the same during the dav and during the night,' but the number of 



