NO. II ATMOSPHERIC OZONIi FOWLE I9 



From the data of the i)receding- tahic and the corresponding figures 

 several phenomena are notable : 



(i) There is a very decided yearly march, as lias hcen noted l)y 

 other observers. 



(a) In the northern hemisphere we may take the maximum and 

 minimum of this march as follows : 



Maximvim Miiiiimun 



1 92 1 March' Sept. 



1922 March Nov. 



1923 April-May Aug. ? 



1924 April Aug. ? 



1925 (April, Dobson) (Oct., Dul)son) 



1926 April-May Oct. 



1927 April-May (Ai)ri], lUiisson) Nov. (Nov.. r)nisson)'' 



1928 May Sept. 



( 1) ) and in the southern hemisphere as follows : 



Maximum Minimum 



1923 Sept. March 



1924 Aug.-Sept. March 



1925 ? Feb. 



1926 Aug. April ? 



1927 not definite not definite. 



whence : 



(2) In the 3'early march the maxima and minima occur at nearly 

 the same seasons of the year in the northern and southern hemi- 

 spheres, though of course not in months of the same name. The 

 maxima occur between April and May, the minima between August 

 and November in the northern hemisphere and vice versa approxi- 

 mately in the southern. 



(3) A marked correlation exists between the ozone and the W'olfer 

 sun-spot numbers for the observations of the northern-hemisphere 

 stations, as indicated in figures lo and ii The range of the yearly 

 means for the area of the yellow band is from 20 to 100 (see fig. 9). 



' The writer is inclined to discount the appearance of the low value in May. 

 1921, as abnormal, possibly due to erroneous observing, and to consider the 

 general march of the curve as indicating the minimum in September. Somewhat 

 similar judgments occur later in the table. 



■ C. R. 186, 1229, 1918. 



