MEMOIRS OF THE LITERARY AND PHILOSOPHICAL SOCIETY OF MANCHESTER

SECOND EDITION

LONDON

PRINTED FOR T. CADWELL IN THE STRAND

MD C C L X X XIX

METEOROLOGICAL IMAGINATIONS and CONJECTURES. By BENJAMIN FRANKLIN, LL.D
F. R. S. and acad. reg. Scient. Paris. Soc. etc. Communicated by Dr.
PERCIVAL. Read December 22, I784.

THERE seems to be a region higher in the air over all countries, where
it is always winter, where frost exitfls continua1ly, fince, in the
midf of fummer on the furface of the earth, ice falls often from above
in the form of hail. Haiftones, of the great weight we fometimes find
them, did not probably acquire their magnitude before they began
todercend. The air, being eight hundred times rarer than water, is
unable to fupport it but in the fhape of vapour a ftate in which its
particles are feparated. As foon as they are condenfed by the cold of
the upper region, fo as to form a drop, that drop begins to fa11.

If it freezes into a grain of ice, that ice defcends. In defcending,
both the drop of water, and the grain of ice, are augmented by
particles of the vapour they pafs through in falling, and'which they
condenfe by their coldnefs, and attach to themfelves. It is pofflble
that, in fummer, much of what is rain, when it arrives at the furface
of the earth~ might have been fnow, when it began its defcent; but
being thawed, in paffng through the warm air near the furface, it is
changed from fnow to rain. How imrnenfely cold muft be the original
particle of hail, which forms the center of the future hailftone, fince
it is capable of communicating fufficient cold, if I may fo fpeak, to
freeze all the mafs of vapour condenfed round it, and form a lump of
perhaps fix or eight ounces in weight.

When, in fummer time, the run is high, and continues long every day
above the horizon, his rays ftrike the earth more directly, and with
longer continuence, than in the winter; hence, the furface is more
heated, and to a greater depth, by the heat of thofe rays.

When rain fa!ls on the heated earth, and falls down into it, it carries
down with it a great part of the heat, which by that means defcends
ftill deeper.

The mafs of earth, to the depth perhaps of thirty feet, being thus
heated to a certain degree, continues to retain its heat for fome time.
Thus the firft fnows that fall in the bsginning of winter, feldom lie
long on the furface, .but are foon melted, and fioon abforbed. After
which, the winds that blow over the country on which the finows had
fallen, are not rendefed fo cold as they would have been by thofe
fnows, if they had remained. And thus the approach of .the feverity of
winter is retarded; and the extreme degree of its cold is not always at
the time we might expect it, viz. when the fun is at its greateft
diftance, and the day fhorteft, but fome time after .that period,
according to the Englifh proverb which fays, "as the day lengthens, the
cold ftrengthens;" the caufes of refigeration continuing to operate,
while the fun returns too flowly and his force continues too weak to
counteract them.

During feveral of the fummer months of thc year 1783, when the effect
of the fun's rays to heat the earth in these northern regions fhould
have been greater, there exifted a conftant fog over all Europe, and
great part of North America- This fog was of a permanent nature; it was
dry, and the rays of the fun feemed to have little effect towards
diffipating it, as they eafily do a moift fog, arifing from water. They
were indeed rendcred fo faint in paffing through it, that when
collefted in the focus of a burning glafs they woul;l fcarce kindle
brown paper.

Of courfe, their fummer effect in heating the earth was exceedingly
diminifhed.

Hence the furface was early frozen;

Hence the firft snows remained on it unmelted, and received continual
additions. Hence the air was more chilled, and the winds more feverely
cold.

Hence perhaps the winter of 1783-4, was mor fevere, than any that had
happened for rnany years.

The caufe of this univerfal fog is not yet afcertained. Whether it was
adventitious to this earth, and merely a fmoke, proceeding from the
confumption by fire of fome of thofe great burning balls or globes
which we happen to meet with in our rapid courfe round the fun, and
which are fomecimes feen to kindle and be deftroyed in paffng our
atmofphere, and whofe fmoke might be attracted and retained by our
earth; or whether it was the vaft quantity of fmoke, long continuing;
to iffue'during the fummer fiom IIecla in Iceland, and that other
volcano which arofe out of the fea near that ifland, which rmoke might
be fpread by various winds, over the northern part of the world, is yet
uncertain. It feems however worth the enquiry, whether other hard
winters, recorded in hiftory, were preceded by fimilar permanent and
widely extended fummer fogs. Becaufe, if found to be fo, men migbt from
fuch.fogs conjecture tbe probability of fucceeding hard winter, and of
the damage. to be expected by the breaking up of frozen rivers in the
fpring; and take fuch measures as are poffible and practicable, to
fecure themfelves and effects from the mirchiefs that attended the
laft.

Passy, May 1784.
http://www.dartmouth.edu/~volcano/Fr373p77.html

It would seem that the year 1783 was not that dissimilar to last year.
Of couse April 2006 hardly counts as winter but hey; he was only posing
some connections he'd come up with. If it can be shown that it was a
year of many hurricanes in the North Atlantic, that would be a
clincher.

I'll be damned if the yanks will insist on calling it the Franklin
Effect. It should be called the McNeil Cycle.