OBSERVATIONS. 
365 
because winds disperse it, and copious dews dilute it, and 
prevent its ill effects. It falls mostly in hazy warm 
weather. 
MORNING CLOUDS. 
Aptee a bright night and vast dew, the sky usually becomes 
cloudy by eleven or twelve o^clock in the forenoon, and 
clear again towards the decline of the day. The reason 
seems to be, that the dew, drawn up by evaporation, occa- 
sions the clouds ; which, towards evening, being no longer 
rendered buoyant by the warmth of the sun, melt away, 
and fall down again in dews. If clouds are watched in a 
still warm evening, they will be seen to melt away, and 
disappear. 
DRIPPING WEATHER AFTER DROUGHT. 
"No one that has not attended to such matters, and taken 
down remarks, can be aware how much ten days^ dripping 
weather will influence the growth of grass or corn after a 
^ severe dry season. This present summer, 1776, yielded a 
remarkable instance; for till the 30th of May the fields 
were burnt up and naked, and the barley not half out of the 
ground ; but now, June 10, there is an agreeable prospect 
of plenty. 
AURORA BOREALIS. 
November 1, 1787. The Northern Aurora made a par- 
ticular appearance, forming itself into a broad, red, fiery 
belt, which extended from E. to W. across the welkin; but 
the moon rising at about ten o'clock, in unclouded majesty 
in the E., put an end to this grand, but awful meteorous 
phenomenon. 
BLACK SPRING, 1771. 
Dr. Johnson says, that *^^in 1771 the season was so severe 
in the island of Skye, that it is remembered by the name of 
the Black Spring. The snow, which seldom lies at all, 
covered the ground fc^ eight weeks, many cattle died, and 
those that survived we/e so emaciated that they did not 
