33 
Ordinary Meeting, November 3rd, 1868. 
J. P. Joule, LL.D., F.R.S., &c., President, in the Chair. 
“Remarks on Mr. Baxendell’s Laws of Atmospheric Ozone,” 
by Professor W. Stanley Jevons, M.A. 
In reading the remarks of Mr. Baxendell on atmospheric 
ozone, it occurs to me that a very simple explanation can be 
given of the connexion he detects between the height of the 
clouds and the amount of ozone at the surface, two facts 
which seem at first sight entirely unrelated The quantity 
of ozone which reaches the surface will depend on three 
circumstances : 
1. The thickness of the current of air touching the surface. 
2. The proportion of ozone existing therein. 
3. The degree in which this current is rendered uniform 
by constant mixture. 
The balloon observations of Mr. Glaisher proved what 
was previously inferred by meteorologists, that the atmo- 
sphere usually consists of several strata of air which are 
separated by distinct boundaries, and do not freely mix. 
Hence it is only the ozone in the lowest stratum which is 
usually available at the surface, and its quantity will he 
proportioned, ceteris paribus, to the thickness of that 
stratum. It is the height of the first layer of clouds which 
usually defines the upper limit of this stratum. For during 
my own observations both in Australia and England I have 
often noticed that smoke from a great town or from exten- 
sive bush fires rises only to a definite height, and seems to 
Pboobedings — Lit. & Phil. Society. — Yol. VIII. — No. 3.— Session 1868-9. 
