MR. J. BAXENDELL ON ATMOSPHERIC OZONE. 201 



January 34'6 July 48*5 



February 30-4 August 52*0 



March 51*8 September 46*6 



April 52*8 October 42*6 



May 63-1 November 38*3 



June 58-5 December 3i"i 



A projection of these numbers is shown in curve No. 4. 

 The means for the seasons are — 



Winter 32-0 



Spring 55-9 



Summer 53*0 



Autumn 42*5 



It appears therefore that the elevation of the clouds is 

 greatest in the spring quarter, when the amount of ozone, 

 according to the Oxford observations, is also greatest, and 

 least in winter, when the amount of ozone is also least. I 

 am not at present aware of the existence of any observa- 

 tions by which it can be ascertained whether this relation 

 holds good in other latitudes. 



It may be objected that the conclusions I have di'awn 

 from the few series of observations to which I have referred 

 rest on an insufficient basis of facts ; and knowing, from 

 long experience in meteorological inquiries, the danger of 

 relying too much on deductions from a limited number of 

 observations, I regard it as very probable that further 

 investigations may render some modifications of my con- 

 clusions necessary. The subject is one in which the me- 

 teorologist requires the aid of the chemist. The method 

 now employed of detecting the presence of ozone in the 

 atmosphere, and measuring its result, is very imperfect ; 

 and the causes of its frequent sudden development and 

 almost equally rapid disappearance are, at present, involved 

 in mystery ; they are, however, as I have sbown, evidently 

 connected with other meteorological phenomena, upon 

 which they may throw much light ; and their importance 

 in a sanitary point of view cannot be doubted. Although, 



