( 580 ) 



ascents distributed over 119 different days; — I have disregarded the 

 observations marked as uncertain in this work. On the whole I have 

 obtained the results on 182 different days, of which 58 with unclouded 

 and 124 with clouded sky. 



The temperature gradients for each month were derived from this 

 material, and to obtain a greater precision, I have combined them in 

 four groups, each of three successive months, December, January and 

 February (winter), March, April and May, (spring), June, July and 

 August, (summer), September, October, November, (autumn). 



TABLE I. 



Variations of temperatures per kilometer. 



(V.T. Variation of temperature per kilometer; N. Number of observations). 



A. Clear sky. 



