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periodicity of ozone intensity nearly identical with the 
periodicity of solar radiation, there is a warranty for con- 
cluding, — 
1st. That ozone is the result of an activity produced in 
oxygen by the direct action of solar radiation. 
2nd. That as a highly compressed, dense, or confined 
atmosphere impedes the effects of direct solar radiation, so 
less ozone is found in valleys and low-lying districts than 
on mountains and highlands. 
3rd. That as direct solar radiation is impeded in large 
towns and populous districts, and the action of oxygen is in 
many ways neutralized, therefore little or no ozone is found 
in such places. 
“ Notes of Comparisons of Ozone Papers,” by G. V. 
Vernon, F.E.A.S., F.M.S. 
Mr. Mackereth, F.RA.S., having kindly supplied me with 
papers prepared by Dr. Moffat’s method, but on unsized 
paper, I thought it would be interesting to see what the 
relative amounts of ozone found would be as compared with 
Dr. Moffat’s ordinary papers. The papers were exposed in 
precisely a similar manner, and quite free from any solar 
influence. 
The observations only extending over a few months, 
there is of course but little to be determined from them so 
far, except the fact of the much greater amount of ozone 
shown by the papers prepared from unsized paper. With 
these papers amounts are frequently registered when the 
sized papers give no indication whatever, and in addition 
to this the average daily amounts are much greater. The 
details I have annexed in Table I. 
