216 
and ozone are intimately related ; and it is not unreasonable 
to suppose that oxygen is more easily rendered active at a 
high position in the atmosphere than a low one, that is, 
rendered more active under a light pressure than under a 
dense one. 
Fifth . — The apparent connexion of Ozone with Solar 
Radiation. Whether we liberate oxygen chemically, or 
by electricity, the force which produces heat has to be 
employed. The source of terrestrial heat is the sun ; and 
this heat, in the main, is the cause of all our atmospheric 
phenomena, especially of those movements of the air called 
winds, and the magnetic and electric storms the great com- 
panions of ozone manifestations. Two important papers 
have been read before this society by Mr. Josh. Baxendell, 
F.R.A.S., “On Solar Radiation,” which have been printed 
in the 7th vol. of the proceedings of the Society. In the 
first of these papers it is shown — 
“ 1st. That the calorific intensity of the sun's light is 
subject to periodical changes, the maxima and minima of 
which correspond respectively with those of the solar spot 
frequency.” 
“ 2nd. That the intensity of a ray of direct sun-light on 
its arrival at the earth’s surface in the latitude of Oxford 
is greater in April and September than in June, when the 
sun’s meridian altitude is greatest. 
“ 3rd. That the curve representing the mean monthly 
values of solar radiation on cloudless days, has its times of 
maxima and minima corresponding with those of the curve 
representing the mean monthly diurnal ranges of the mag- 
netometer.” 
And at page 105, Mr. Baxendell further shows “That 
clouds and haze are less prevalent during the day, or their 
power to intercept the heating rays of the sun is less active 
in the spring and autumn than in, the winter and summer 
months.” In the first of these papers, Mr. Baxendell gives 
