JULY 
289 
less : in that case I presume we do not see the flash itself^ 
but the illumination of the atmosphere consequent on it ; 
the reflection in the sky^ as it is called ; the clouds contain- 
ing the electricity being beneath the horizon^ and therefore 
invisible. 
C. — What an exhilarating freshness and purity there is 
in the air^ this morning ; similar to that which is perceived 
on mountain summits, or any great elevation. 
F, — For this we are indebted to the trees and plants 
around us : all vegetables give out oxygen by day^ the life- 
giving part of the air we breathe ; but after the excitement 
of a thunder-storm^ it is evolved in much greater profusion^ 
which has a refreshing and enlivening effect on animal 
spirits. 
C. — How delightfully fresh and green the trees and 
herbage look ! the leaves are yet sparkling with the rain- 
drops : see the long^ seedy grass bowing its heavy head 
under the weight of moisture ; what a silvery appearance it 
has ! it is almost ready for the scythe. 
F. — Let us climb this hill^ whence we may look down 
on the lowlands and bottoms. — I should have rather said, 
we can look towards them ; for I perceive they are hidden 
by a dense film of mist or fog, that lies upon them. 
C. — What is the cause of its covering the land so par- 
tially ? 
F, — When the rain fell last nighty the earth had been 
heated to a considerable extent: much of the water was 
evaporated^ and rose in invisible vapour^ but now that the 
morning air is cool^ the vapour is condensed^ and falls in the 
form of a thick fog upon the low lands. Often during a 
season of dry weather, if we stand on a hill at early day 
light, we may trace the river through all its circuitous wind- 
ings through the forest, (though no part of it is visible,) by 
the belt of white fog which hangs over it, but which is 
