310 West and North-west Winds of New-England. 
rupted. The three last days the mercury stood at five, 
eight, and eleven, degrees below cypher. In 1787 the 
same wind began to blow about the 20th of November, and 
continued its progress, with only four short interruptions, 
until the 20th of the following March : somewhat more 
than one hundred days. During this whole period, the 
weather was, for the season, very cold. On the third 
Tuesday in February the mercury sunk to fourteen degrees 
below zero : lower than it is known to have fallen at any 
place on the sound, except once since the settlement of 
the country. as 
I began to form the opinion, that these winds descended 
at times, from the superior regions of the atmosphere, from 
the following occurrence. 1 was standing on Greenfield 
Hill, where I then lived ; (a natural observatory, comman- 
ding an extensive and unobstructed horizon,) and watching 
the phenomena of the heavens in a summer afternoon : 
when IJ was struck with the appearance of a very small, 
dark cloud, distant from me about four or five miles in the 
west. I perceived that it became, rapidly, more and more 
dark, and increased with equal rapidity in its size. Speed- 
ily after I fixed my eye upon it, it began to move with a 
considerable velocity towards the south-east ; enlarging 
its dimensions, and deepening its hue, every moment of 
its progress. Within a few minutes it emitted a flash of 
lightning, succeeded by a peal of thunder: and within a 
few minutes more, a stream of rain, continually increasing, 
descended from its skirts. The lightning and thunder 
soon became frequent, and the clouds speedily assumed all 
the usual appearances ofa thunder-storm. The meridional 
line, upon which [ stood, it crossed, several miles to the 
South : and, by the time that it had traversed half the 
breadth of the Sound, a distance of fourteen miles from 
Greenfield Hill, it extended over a fourth, or fifth, part 
of the horizon. sideh. ah 
During the whole day the wind had blown from the 
south-west; and continued to blow in the same direction, 
on the surface, throughout the afternoon, without a moment's 
intermisston. But, had the wind, which carried the cloud, 
_when it passed over the regions south-west of Greenfield, 
swept the surface; the progress of the south-west wind 
must, for some time at least, have been entirely stopped, 
