METEOROLOGICAL OBSERVATIONS. 
303 
METEOEOLOGICAL OBSEEYATIONS. 
BAROMETEK. 
November 22, 1768. A remarkable fall of the barometer all over the 
kingdom. At Selborne we had no wind, and not much rain ; only vast, 
swagging, rock-like clouds appeared at a distance. — White. 
PARTIAL FROST. 
The country people, who are abroad in winter mornings long before 
sunrise, talk much of hard frost in some spots, and none in others. The 
reason of these partial frosts is obvious, for there are at such times 
partial fogs about ; where the fog obtains, little or no frost appears ; 
but where the air is clear, there it freezes hard. So the frost takes 
place either on hill or in dale, wherever the air happens to be clearest 
and freest from vapour. — White. 
THAW. 
Thaws are sometimes surprisingly quick, considering the small 
quantity of rain. Does not the warmth at such times come from 
below ] The cold in still, severe seasons seems to come down from 
above ; for the coming over of a cloud in severe nights raises the ther- 
mometer abroad at once full ten degrees. The first notices of thaws 
often seem to appear in vaults, cellars, &c. 
If a frost happens, even when the ground is considerably dry, as soon 
as a thaw takes place, the paths and fields are all in a batter. Country 
people say that the frost draws moisture. But the true philosophy is, 
that the steam and vapours continually ascending from the earth, are 
bound in by the frost, and not suffered to escape till released by the 
thaw. No wonder then that the surface is all in a float ; since the 
quantity of moisture by evaporation that arises daily from every acre of 
ground is astonishing. — White. 
FROZEN SLEET. 
January 20. Mr. H.'s man says that he caught this day in a lane 
near Hackwood park, many rooks, which, attempting to fly, fell from 
the trees with their wings frozen together by the sleet, that froze as it 
fell. There were, he affirms, many dozen so disabled. — White. 
MIST, CALLED LONDON SMOKE. 
This is a blue mist which has somewhat the smell of coal smoke, and 
as it always comes to us with a N.E. wind, is supposed to come from 
