After the communications, which we have received from several of our
correspondents in different parts of the continent, acquainting us
with the success of their experiments last summer, in endeavouring to
extract the electricity from the atmosphere during a thunder-storm,
in consequence of Mr. Franklin's hypothesis, it may be thought
extraordinary, that no accounts have been yet laid before you, of our
success here from the same experiments. That no want of attention,
therefore, may be attributed to those here, who have been hitherto
conversant in these enquiries, I thought proper to apprise you, that,
though several members of the Royal Society, as well as myself, did,
upon the first advices from France, prepare and set up the necessary
apparatus for this purpose, we were defeated in our expectations,
from the uncommon coolness and dampness of the air here, during the
whole summer. We had only at London one thunder-storm; viz. on July
20; and then the thunder was accompanied with rain; so that, by
wetting the apparatus, the electricity was dissipated too soon to be
perceived upon touching those parts of the apparatus, which served
to conduct it. This, I say, in general prevented our verifying Mr.
Franklin's hypothesis: but our worthy brother, Mr. Canton, was more
fortunate. I take the liberty, therefore, of laying before you an
extract of a letter, which I received from that gentleman, dated from
Spital-square, July 21, 1752.
"I had yesterday, about five in the afternoon, an opportunity of
trying Mr. Franklin's experiment of extracting the electrical fire
from the clouds; and succeeded, by means of a tin tube, between three
and four feet in length, fixed to the top of a glass one, of about
eighteen inches. To the upper end of the tin tube, which was not
so high as a stack of chimnies on the same house, I fastened three
needles with some wire; and to the lower end was soldered a tin cover
to keep the rain from the glass tube, which was set upright in a
block of wood. I attended this apparatus as soon after the thunder
began as possible, but did not find it in the least electrified,
till between the third and fourth clap; when, applying my knuckle
to the edge of the cover, I felt and heard an electrical spark; and
approaching it a second time, I received the spark at the distance of
about half an inch, and saw it distinctly. This I repeated four or
five times in the space of a minute, but the sparks grew weaker and
weaker; and in less than two minutes the tin tube did not appear to
be electrified at all. The rain continued during the thunder, but was
considerably abated at the time of making the experiment." Thus far
Mr. Canton.
Mr. Wilson likewise of the Society, to whom we are much obliged for
the trouble he has taken in these pursuits, had an opportunity of
verifying Mr. Franklin's hypothesis. He informed me, by a letter from
near Chelmsford, in Essex, dated August 12, 1752, that, on that day
about noon, he perceived several electrical snaps, during, or rather
at the end of a thunder-storm, from no other apparatus than an iron
curtain rod, one end of which he put into the neck of a glass phial,
and held this phial in his hand. To the other end of the iron he
fastened three needles with some silk. This phial, supporting the
rod, he held in one hand, and drew snaps from the rod with a finger
of his other. This experiment was not made upon any eminence, but in
the garden of a gentleman, at whose house he then was.
Dr. Bevis observed, at Mr. Cave's, at St. John's Gate, nearly the
same phenomena as Mr. Canton, of which an account has been already
laid before the public.
Trifling as the effects here mentioned are, when compared with those
which we have received from Paris and Berlin, they are the only ones,
that the last summer here has produced; and as they were made by
persons worthy of credit, they tend to establish the authenticity of
those transmitted from our correspondents.
I flatter myself, that this short account of these matters will not
be disagreeable to you; and am,
With the most profound respect,
Your most obedient, humble servant,