OF SELBORNE. 
301 
On chalky and fandy foils, and in the hot villages about London, 
the thermometer has been often obferved to mount as high as 83 
or 84 ; but with us, in this hilly and woody diftri6l, I have hardly 
ever feen it exceed 80 ; nor does it often arrive at that pitch. 
The reafon, I conclude, is, that our denfe clayey foil, fo much 
fhaded by trees, is not fo eafily heated through as thofe above- 
mentioned : and, befides, our mountains caufe currents of air and 
breezes ; and the vaft effluvia from our woodlands temper and 
moderate our heats. 
LETTER LXIV, 
TO THE SAiME, 
The fummer of the year 1783 was an amazing and portentous 
one, and full of horrible phenomena ; for, belides the alarming 
meteors and tremendous thunder-ftorms that affrighted and dif- 
trelTed the different counties of this kingdom, the peculiar haze, 
or fmokey fog, that prevailed for many weeks in this illand, and 
in every part of Europe, and even beyond it's limits, was a moft 
extraordinary appearance, unlike any thing known within the 
memory of man. By my journal 1 find that I had noticed this 
ftrange occurrence from June 23 to July 20 inclufive, during which 
period the wind varied to every quarter without making any alter- 
ation 
