MR. J. BAXENDELL ON ATMOSPHERIC OZONE. 191 



this manner, they lead us to conclude that such rocks 

 were formed under very great pressure, varying in different 

 cases, but of such a magnitude as clearly points to their 

 deep-seated plutonic origin.^' 



Those interested in this inquiry may consult the paper 

 by Sir David Brewster in the Transactions of the Royal 

 Society of Edinburgh, Mr. Sorby^s paper in the Report of 

 the British Association Meeting at Leeds, also his paper 

 in the Quarterly Journal of the Geological Society, vol. 

 xiv., and a paper entitled " The Microscope in Greology,^^ 

 in the ^Popular Science Review' for October 1867, by 

 David Forbes, F.R.S. 



Note. — My thanks are due to E. W. Binney, Esq., F.R.S., Joseph Man- 

 chester, Esq., and J. W. Botsford, Esq., for the loan of crystals and precious 

 stones containing fluid-cavities, some of which are described in this paper. 



XII. On Observations of Atmospheric Ozone. 

 By Joseph Baxendell, F.R.A.S. 



Eead October 20th, 1868. 



The remarkable nature of the conclusions arrived at by 

 Mr. Mackereth, F.R.A.S., in his paper " On Ozone and 

 its Probable Connexion with Solar Radiation,^' read at the 

 meeting of the Physical and Mathematical Section held on 

 the 2 1st of April last, has led me to examine and discuss 

 the series of ozone observations made at the Radcliffe Ob- 

 servatory, Oxford, during the years 1856-65, as well as 

 several other series which have fallen under my notice. It 

 will be seen, from the results which I now proceed to give, 

 that Mr. Mackereth^s conclusions are not borne out, but 

 that nevertheless the subject of atmospheric ozone is one 

 of much interest, and merits more attention on the part 

 of meteorologists and physicists than it has yet received. 



