MR. J. BAXENDELL ON ATMOSPHERIC OZONE. 195 



Grouping the Eccles and Oxford monthly means accord- 

 ing to the seasons, we have the following results : — 



Eccles. Oxford. 



Winter i"28 275 



Spring 2'i3 4*56 



Summer 1*37 4*23 



Autumn 0*89 2*90 



Both at Eccles and Oxford the maximum occurs in the 

 spring j but the minimum occurs at Eccles in the autumn, 

 and at Oxford in the early part of winter. 



The Rev. Robert Main, F.R.S., Director of the Radcliffe 

 Observatory, Oxford, has kindly favoured me with a copy 

 of the unpublished results of his ozone observations for 

 the years 1866 and 1867; and although he believes that 

 the results for 1866 cannot be relied on, owing to test- 

 papers of an unsatisfactory quality having been used during 

 a considerable portion of that year, yet the means for the 

 two years, which are 4*57 for 1866 and 4* 12 for 1867, bear 

 out very fairly the conclusions I have drawn from the 

 results of the previous ten years' observations, the amounts 

 being above the average of the entire series, and corre- 

 sponding to a sun-spot frequency considerably below the 

 average. 



Observations at the Lisbon Observatory. 



The first volume of the Annals of the Lisbon Observa- 

 tory contains a table of the monthly and annual results 

 of a series of ozone observations made during the years 

 1856-63. The mean monthly amounts of ozone were as 

 follows : — 



o2 



