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212 Phyfion . De electricitate 308
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EXPERIMENTS AND
OBSERVATIONS ΟΝ
ELECTRICITY, MADE AT
PHILADELPHIA in AMERICA .

1

EXPERIMENTS AND
OBSERVATIONS ΟΝ
ELECTRICITY, MADE AT 1
PHILADELPHIA in AMERICA, BY
BENJAMIN FRANKLIN , L. L. D. and F. R. S.
To which are added , LETTERS and PAPERS
ON PHILOSOPHICAL SUBJECTS .
The Whole corrected, methodized, improved, and now firſt col lected into one Volume, AND
Illuftrated with COPPER PLATES.
LONDON : Printed for DAVID HENRY ; and fold by FRANCIS NEWBERY ,
at the Corner of St. Paul's Church-Yard. MDCCLXIX .

BIBLIOTHECA REGIA
MONACENSIS 4
3
31 1

PREFACE To the First Edition .

may be neceſſary to acquaint the Reader, that thefol lowing obfervations and experiments were not drawn up

with a view to their being made publick, but were com

1

municated at different times, and most of them in letters wrote

on various topicks, as matters only ofprivate amusement. But fome perfons to whom they were read, and who had

themſelves been converfant in electrical difquifitions, were of opinion, they containedfo many curious and interefting particu lars relative to this affair, that it would be doing a kind of in juftice to the public, to confine them folely to the limits of a

private acquaintance.

The Editor was therefore prevailed upon to commit fuch ex

tracts ofletters, and other detached pieces as were in his hands

to the prefs, without waiting for the ingenious author's per miffion fo to do ; and this was done with the lefs befitation, as

it was apprehended the author's engagements in other affairs wouldfcarce afford him leifure to give the publick his reflecti ons and experiments on the fubject, finished with that care and

precifion, of which the treatife before us fhews he is alike ftudi ous and capable.

The experiments which our author relates are most of them peculiar to himself; they are conducted with judgment, and the

inferences from them plain and conclufive ; though fometimes

propofed under the terms offuppofitions and conjectures . And indeed the fcene he opens, ftrikes us with a pleafing
aftonishment, while he conducts us by a train offacts and ju dicious reflections, to a probable caufe of thofe phænomena,

which are at once the most awful, and, hitherto, accountedfor with the leaft verifimilitude.

He

iv

PREFACE.

He exhibits to our confideration, an invifible, fubtle matter;
diffeminated through all nature in various proportions, equally
unobferved, and, whilst all those bodies to which it peculiarly adheres are alike charged with it, inoffenfive.
He fhews, however, that if an unequal diftribution is by any means brought about ; if there is a coacervation in one part of Space, a lefs proportion, vacuity, or want, in another ; by the near approach of a body capable ofconducting the coacervated part to the emptier Space, it becomes perhaps the moſt formid able and irrefiftible agent in the univerfe . Animals are in an inftant ftruck breathless, bodies almost impervious by anyforce
yet known, are perforated, and metals fufed by it, in a mo ment .

From the fimilar effects of lightning and electricity, our au thor has been led to makefome probable conjectures on the caufe

of the former ; and, at thefame time, to propofe fome rational

1

I

experiments in order to fecure ourselves, and those things on

I

which its force is often directed, from its pernicious effects ; a

circumftance of no fmall importance to the publick, and therefore worthy of the utmost attention.

It has, indeed, been oflate the fashion to afcribe every grand

or unusual operation of nature, fuch as lightning and earth-.

quakes, to electricity ; not, as one would imagine from the

manner of reafoning on thefe occafions, that the authors of

thefe fchemes have difcovered any connection betwixt the caufe,

and effect, or faw in what manner they were related ; but, as it wouldfeem, merely because they were unacquainted with any

other agent, of which it could not pofitively be faid the connec tion was impoffible.

But of thefe, and many other interesting circumftances, the

reader will be more fatisfactorily informed in the following

letters, to which he is therefore referred by

The EDITOR ..

ADVERTISEMENT
Concerning this Fourth Edition .
L L the Philoſophical Letters and Papers of Α 'the fame Author, that have been inſerted at different Times in the Philofophical Tranfac tions of the Royal Society, or in the Magazines, or printed in ſeparate Pamphlets , are collected and added to this Edition ; together with a Num ber of others on various Subjects , never before printed, that have paffed between the Author and his Friends. Many Errors in the preceding Edi tions, are now corrected ; fome of the Letters , which had been tranſpoſed, are reſtored to their proper places ; and fundry Paſſages are more ful ly explained by Notes .----There is alſo added, a compleat Index to the whole .

ERRAT A.

AGE 13 , Line 8, for, at top, read, at the top. PAGE
50, -15, add, becauſe the blood and other humours
containing fo much water, are more ready conductors .

62-10 for wrote, read written.

73,10, for prevades, read, pervades.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

96,

7, from the bottom : add, ( page 54 of this Edit..

127, ——22, for, diſcoveries, you read diſcoveries, you .

134,

3, for Lyden, read Leyden.

141 , -20, for give it a fhock, read, give a fhock.

143 ,—11 , for experimen, read, experiment.

158,-22, for they, read, you.

189, — 5, for infenfibly, read, infenfibly. 199,—15, for fettle, read fettle.

225, 327 344,

3 , add, See plate II . f
7 for by frequent, read, by the frequent.
3 , from the bottom, begin a new paragraph at
There.

345, 346

4, from the bottom, begin a new paragraph at How.
-20 , dele the comma at reproduced, and put one
at feparation.

347 ,————— 11 , for has the ſame, read, has nearly the fame.

354,

2, from the bottom, for 280 , read 180 .

389-11 , add See plate . VI.

403,15. for VI. read VII.

475,

2 , for endeabour, read endeavour.

490,18 , dele the femicolon between warmer and fitu

ation .

In numbering of the pages, 112 , 113, are repeated ; as are alſo

pages 465 to 472 .

Plate. 1. Fig . I.
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EXTRA

C

T

OF

LETTER F.RO M

I.

BENJ . FRANKLIN , Efq; at Philadelphia, то
PETER COLLINSON, Efq; F. R.S. London.

SIR,

Philadelphia, March 28, 1747.

OUR kind preſent of an electric tube, with directions for ufing it, has put fe

veral of us on making electrical expe riments, in which we have obſerved

ſome particular phænomena that we look upon to be new. I fhall, there

fore communicate them to you in my next, though pof

B

fibly,

2

New Experiments and

fibly they may not be new to you, as among the numbers

daily employed in thofe experiments on your fide the wa

ter, ' tis probable ſome one or other has hit on the fame ob ſervations. For my own part, I never was before engaged

in any ſtudy that ſo totally engróffed my attention and my time as this has lately done ; for what with making expe riments when I can be alone, and repeating them to my

Friends and Acquaintance, who, from the novelty of the

thing, come continually in crouds to ſee them, I have, du ring fome months paſt, had little leiſure for any thing elſe.

I am, &c. B. FRANKLIN.

******

LET •

Obfervations on ELECTRICITY.

3

LETTER FROM

II .

Mr BENJ . FRANKLIN , in Philadelphia, TO

PETER COLLINSON, Efq; F. R. S. London.

SIR,

July 11 , 1747.

my laft I informed you that, in purſuing our electri INcal enquiries, we had obſerved ſome particular Phæno mena, which we looked upon to be new, and of which I

promiſed to give you fome account, though I apprehended they might poffibly not be new to you, as fo many hands are daily employed in electrical experiments on your fide the water, fome or other of which would probably hit on the fame obfervations.

The first is the wonderful effect of pointed bodies, both in drawing offand throwing off the electrical fire . For example,
Place an iron fhot ofthree or four inches diameter on the

mouth of a clean dry glaſs bottle. By a fine filken thread

from the cieling, right over the mouth of the bottle, fuf

pend a ſmall cork- ball, about the bignefs of a marble ; the

B2

thread

dukaacbaidt2teta5c6aslmă”.,-"a

4

New Experiments and

thread of fuch a length , as that the cork -ball may reft against the fide of the fhot. Electrify the fhot, and the

ball will be repelled to the diſtance of four or five inches, more or leſs, according to the quantity of Electricity. When in this ſtate, if you prefent to the hot the point of a long flender ſharp bodkin, at fix单 or eight inches diſtance, the repellency is inftantly deftroy'd, and the cork flies to

the ſhot. A blunt body must be brought within an inch, and draw a ſpark, to produce the fame effect. To prove that the electrical fire is drawn off by the point, if you take the blade of the bodkin out of the wooden handle, and fix

it in a ſtick of ſealing-wax, and then prefent it at the dif

tance aforefaid, or if you bring it very near, no fuch effect

follows ; but fliding one finger along the wax till .you touch the blade, and the ball flies to the ſhot immediately.
If you prefent the point in the dark , you will fee, fome

times at a foot diſtance, and more, a light gather upon it,

‫ھد‬

like that of a fire- fly, or glow- worm ; the lefs fharp the

point, the nearer you muſt bring it to obferve the light ; and at whatever diſtance you ſee the light, you may draw off the electrical fire, and deftroy the repellency.— If a

cork-ball ſo ſuſpended be repelled by the tube, and a point be prefented quick to it, tho' at a confiderable diſtance, 'tis furprizing to ſee how fuddenly it flies back to the tube. Points of wood will do near as well as thofe of iron, provi

ded the wood is not dry ; for perfectly dry wood will no

more conduct Electricity than fealing-wax.

To

Obfervations on ELECTRICITY .

5

To fhew that points will throw off * as well as draw off the electrical fire ; lay a long fharp needle upon. the ſhot,

and you cannot electrife the ſhot, fo as to make it repel the cork-ball †.—Or fix a needle to the end of a ſuſpended gun barrel, or iron -rod , fo as to point beyond it like a little bayonet ; and while it remains there, the gun-barrel, or rod , cannot by applying the tube to the other end be elec trifed fo as to give a fpark, the fire continually running out filently at the point. In the dark you may fee it make the fame appearance as it does in the cafe before- mentioned .

The repellency between the cork- ball and the ſhot is likewiſe deſtroy'd. 1. By fifting fine fand on it ; this does it gradually. 2. By breathing on it. 3. By making a ſmoke about it from burning wood ‡. 4. By candle light, even though the candle is at a foot diſtance : thefe do it fuddenly. The light of a bright coal from a wood fire ; and

This power of points to throw off the electrical fire, was firft com municated to me by my ingenious friend Mr Thomas Hopkinfon, fince deceaſed, whofe virtue and integrity, in every ftation of life, public and private, will ever make his Memory dear to thofe who knew him , and knew how to value him.
+ This was Mr Hopkinfon's Experiment, made with an expectation of drawing a more ſharp and powerful fpark from the point, as from a kind of focus, and he was furprized to find little or none.
We fuppofe every particle of fand, moisture, or fmoke, being first at tracted and then repelled, carries off with it a portion of the electrical fire ; but that the fame ftill fubfifts in thofe particles, till they communicate it to fomething elfe, and that it is never really deftroyed.-- So when water is thrown on common fire, we do not imagine the element is thereby deftroyed or annihilated, but only difperfed, each particle of water carrying off in vapour its portion of the fire, whichit had attracted and attached to itſelf.
the

6 New Experiments and
the light of red-hot iron do it likewife ; but not at fo great "
a diſtance. Smoke from dry rofin dropt on hot iron, does not destroy the repellency ; but is attracted by both ſhot and cork-ball, forming proportionable atmoſpheres round them, making them look beautifully, fomewhat like ſome of the figures in Burnet's or Whiftor's theory of the earth .
N. B. This experiment fhould be made in a cloſet, where the air is very ftill, or it will be apt to fail .
The light of the fun thrown ftrongly on both cork and fhot by a looking- glafs for a long time together, does not impair the repellency in the leaft. This difference between fire- light and fun- light is another thing that feems new and extraordinary to us *.
We had for fome time been of opinion , that the electri cal fire was not created by friction, but collected, being really an element diffus'd among, and attracted by other matter, particularly by water and metals. We had even diſcovered and demonftrated its afflux to the electrical
ſphere, as well as its efflux, by means of little light wind mill wheels made of ſtiff paper vanes, fixed obliquely and turning freely on fine wire axes. Alfo by little wheels of the fame matter, but formed like water-wheels . Of the

This different Effect probably did not arife from any difference in

the light, but rather from the particles feparated from the candle, being firſt

attracted and then repelled, carrying off the electric matter with them ;

and from the rarefying the air, between the glowing coal or red-hot iron,

and the electrifed fhot, through which rarified air the electric fluid could

more readily pafs .

dif

•

Obfervations on ELECTRICITY.
difpofition and application of which wheels , and the various phænomena refulting, I could, if I had time, fill you a fheet . The impoffibility of electrifing one's felf ( though ſtanding on wax ) by rubbing the tube, and drawing the fire from it ; and the manner of doing it, by paffing the tube near a perfon or thing ftanding on the floor, &c. had alfo occurred to us fome months before Mr Watfon's inge nious Sequel came to hand, and thefe were fome of the
C new things I intended to have communicated to you. But now I need only mention fome particulars not hinted in that piece, with our reafonings thereupon ; though per haps the latter might well enough be ſpared .
1. A perfon ſtanding on wax, and rubbing the tube, and another perſon on wax drawing the fire, they will both of them , (provided they do not ftand fo as to touch one ano ther) appear to be electrifed, to a perfon ſtanding on the floor ; that is, he will perceive a fpark on approaching each of them with his knuckle.
2. But if the perfons on wax touch one another during the exciting of the tube, neither of them will appear to be electrifed .
3. If they touch one another after exciting the tube, and drawing the fire as aforefaid, there will be a ftronger
+ Thefe experiments with the wheels were made and communicated to me by my worthy and ingenious friend Mr Philip Syng ; but we after wards difcovered that the motion of thofe wheels was not owing to any af flux or efflux of the electric fluid, but to various circumftances of attraction and repulfion. 1750.
fpark

8 New Experiments and
fpark between them, than was between either of them and the perfon on the floor .
4. After fuch strong fpark, neither of them difcover any electricity.
Thefe appearances we attempt to account for thus : We
fuppofe, as aforefaid , that electrical fire is a common ele ment, of which every one of the three perfons abovemen tioned has his equal fhare, before any operation is begun. with the tube. A, who ftands on wax and rubs the tube, collects the electrical fire from himſelf into the glafs ; and his communication with the common ftock being cut off
by the wax, his body is not again immediately ſupply'd. B, (who ftands on wax likewife) paffing his knuckle along near the tube, receives the fire which was collected by the glafs from A, and his communication with the common ftock being likewife cut off, he retains the additional quan
tity received.—To C, ftanding on the floor, both appear to be electrifed : for he having only the middle quantity, of electrical fire, receives a fpark upon approaching B, who has an over quantity ; but gives one to A, who has an un der quantity. If A and B approach to touch each other, the fpark is ftronger, becauſe the difference between them is greater : After fuch touch there is no fpark between ei ther of them and C, becauſe the electrical fire in all is re duced to the original equality. If they touch while elec trifing, the equality is never deſtroy'd, the fire only circu lating. Hence have arifen fome new terms among us : we fay, B, (and bodies like circumftanced) is electrifed
pofitively;

Obfervations on ELECTRICITY .

9

pofitively ; A, negatively. Or rather, B is electriſed plus ; A, minus. And we daily in our experiments electrife bodies plus or minus, as we think proper.-To electrife plus or minus, no more needs to be known than this, that the parts of the tube or ſphere that are rubbed , do, in the

inftant of the friction, attract the electrical fire, and there fore take it from the thing rubbing : the fame parts imme diately, as the friction upon them ceafes, are difpofed to give the fire they have received, to any body that has lefs. Thus you may circulate it, as Mr Watfon has fhewn ; you may alfo accumulate or fubtract it upon, or from any body. as you connect that body with the rubber or with the re ceiver, the communication with the common ſtock being cut off. We think that ingenious gentleman was deceived when he imagined (in his Sequel) that the electrical fire came down the wire from the cieling to the gun barrel, thence to the ſphere, and fo electrifed the machine

and the man turning the wheel, &c. We fuppofe it was driven off, and not brought on through that wire ; and that the machine and man, &c. were electrifed minus ; i. e. had

leſs electrical fire in them than things in common. As the veffel is juſt upon failing, I cannot give you fo
large an account of American Electricity as I intended : I

ſhall only mention a few particulars more. —We find gra nulated lead better to fill the phial with, than water, being

eafily warmed, and keeping warm and dry in damp air.

We fire ſpirits with the wire of the phial. - We light

candles, juft blown out, by drawing a ſpark among the

с

(moke

10

New Experiments and

fmoke between the wire and fouffers . We reprefent

lightning, by paffing the wire in the dark, over a china

plate that has gilt flowers, or applying it to gilt frames of

looking- glaffes, &c. We electrife a perfon twenty or 'more times running, with a touch of the finger on the wire, thus : He ftands on wax. Give him the electrifed

bottle in his hand. Touch the wire with your finger, and then touch his hand or face ; there are fparks every time *.-We increafe the force of the electrical kifs vaftly, thus : Let A and B ftand on wax ; or A on wax, and B

on the floor ; give one of them the electrifed phial in hand ; let the other take hold of the wire ; there will be a

fmall fpark ; but when their lips approach, they will be ftruck and fhock'd . The fame if another gentleman and

lady, C and D, ftanding alfo on wax, and joining hands with A and B, falute or fhake hands. We fufpend by fine filk thread a counterfeit ſpider, made of a ſmall piece of burnt cork, with legs of linnen thread, and a grain or two of lead ftuck in him , to give him more weight. Upon the table over which he hangs, we ſtick a wire upright, as

high as the phial and wire, two or three inches from the

ſpider : then we animate him, by fetting the electrified phial at the fame diftance on the other fide of him ; hẹ will immediately fly to the wire of the phial, bend his legs

* By taking a fpark fromthe wire , the electricity within the bottle is diminifhed ; the outfide of the bottle then draws fome from the perfon holding it, and leaves him in the negative ftate. Then when his hand or face is touch'd, an equal quantity is reftored to him from the person touch ing.
in
A

Obfervations on ELECTRICITY.

ff

in touching it ; then ſpring off, and fly to the wire in the table ; thence again to the wire of the phial, playing with his legs against both, in a very entertaining manner, ap pearing perfectly alive to perfons unacquainted. He will continue this motion an hour or more in dry weather. -We electrify, upon wax in the dark , a book that has a double

line of gold round upon the covers, and then apply a knuckle to the gilding ; the fire appears every where upon

the gold like a flash of lightning: not upon the leather, nor, ifyou touch the leather inftead of the gold . We rub our tubes with buckskin , and obferve always to keep the fame fide to the tube, and never to fully the tube by hand ling ; thus they work readily and eafily, without the leaft fatigue, eſpecially if kept in tight paſteboard cafes, lined with flannel, and fitting cloſe to the tube * . This Emen tion becauſe the European papers on Electricity, frequently

fpeak of rubbing the tube, as a fatiguing exerciſe. Our fpheres are "fixed on iron axes, which pass through them. At one end ofthe axis there is a ſmall handle, with which

you turn the ſphere like a common grindfone. This we find very commodious, as the machine takes up but little room, is portable, and may be encloſed in a tight box, when. not in ufe. ' Tis true, the fphere does not turn fo fwift as when the great wheel is used but ſwiftneſs we think of little

importance, fince a few turns will charge the phial,, &c,

fufficiently +.

I am, &c..

B. FRANKLIN,

Our tubes are made here of green glaſs , 27 or 30 inches long, as big as can be grafped,
+ This fimple eafily- made machine was a contrivance of Mr Syng's.

b(maadn1bdsa2t G

NOORDSRAAGNSAT

12

New Experiments and .:

LETTER " III . FROM

BENJ . FRANKLIN , Efq; at Philadelphia, TO
PETER COLLINSON, F. R. S. London.

SIR,

Sept. 1 , 1747.

HE neceffary trouble of copying long letters, which,

ΤΗ perhaps, when they come to your hands, may con

tain nothing new, or worth your reading, ( fo quick is the

progrefs made with you in Electricity ) half diſcourages

me from writing any more on that fubject. Yet I cannot

I

forbear adding a few obfervations on M. Mufchenbroek's

wonderful bottle.

1. The non-electric contain'd in the bottle differs when

electrifed from a non-electric electrifed out of the bottle, in this : that the electrical fire of the latter is accumulated on

its furface, and forms an electrical atmoſphere round it of con

Obfervations on ELECTRICITY.

13

confiderable extent ; but the electrical fire is crowded into

the fubftance of the former, the glafs confining it *. 2. At the fame time that the wire and top of the bot

tle, & c. is electrifed pofitively or plus, the bottom of the bottle is electrifed negatively or minus, in exact propor

tion : i. e. whatever quantity of electrical fire is thrown in at top, an equal quantity goes out of the bottom +. To underſtand this, fuppofe the common quantity of electri

city in each part of the bottle, before the operation begins, is equal to 20 ; and at every ſtroke of the tube, ſuppoſe a quantity equal to 1 is thrown in ; then, after the firft

ftroke, the quantity contain'd in the wire and upper part of the bottle will be 21 , in the bottom 19. " After the fecond, the upper part will have 22, the lower 18 , and

fo on, till, after 20 ftrokes, the upper part will have a quan

tity of electrical fire equal to 40, the lower part none : and then the operation ends : for no more can be thrown into the upper part, when no more can be driven out of the

lower part. If you attempt to throw more in, it is fpued back through the wire, or flies out in loud cracks through the fides of the bottle.

3. The equilibrium cannot be reftored in the bottle by inward communication or contact of the parts ; but it muſt be done by a communication form'd without the

* See this opinion rectified in Letter IV. § 16 and 17. The fire in the bottle was found by fubfequent experiments not to be contained in the non-electric, but in the glass. 1748 .
+ What is faid here, and after, of the top and bottom of the bottle, is true of the infide and outfide furfaces, and fhould have been fo expreffed.
bottle

14

New Experiments and

bottle between the top and bottom, by fome non- electric,

touching or approaching both at the fame time ; in which A

cafe it is reſtored with a violence and quickneſs inexpreffi * ble ; or, touching each alternately, in which caſe the equi

librium is reftored by degrees . 4. As no more electrical fire can be thrown into the M
top of the bottle , when all is driven out of the bottom ,
fo in a bottle not yet electrifed, none can be thrown into: 1
the top, when none can get out at the bottom ; which •
happens either when the bottom is too thick, or when
the bottle is placed on an electric per fe. Again, when the bottle is électrifed, but little of the electrical fire can

be drawn out from the top, by touching the wire, unlefs> an equal quantity can at the fame time get in at the bot

tom . Thus, place an electrifed bottle on clean glafs or:
dry wax, and you will not, by touching the wire, get out: .
the fire from the top. Place it on a non-electric, and

touch the wire, you will get it out in a fhort time ; but fooneft when you form a direct communication as above..

So wonderfully are theſe two ftates of Electricity, the plus and minus, combined and balanced in this miraculous bottle ! fituated and related to each other in a manner that

I can by no means comprehend ! If it were poffible that a bottle fhould in one part contain a quantity of air ſtrongly compreft, and in another part a perfect vacuum, we know the equilibrium would be inftantly restored within. But

* See the preceding note, relating to top and bottom.

here

Obfervations on ELECTRICITY.

15

here we have a bottle containing at the fame time a plenum of electrical fire, and a vacuum of the fame fire' ; and yet the equilibrium cannot be restored between them but by a communication without ! though the plenum preſſes vio lently to expand, and the hungry vacuum feems to attract as violently in order to be filled..

5. The ſhock to the nerves (or convulfion rather) is oc cafioned by the fudden paffing of the fire through the body in its way from the top to the bottom of the bottle. The fire takes the ſhorteſt courfe, as Mr Watfon juftly

obferves : But it does not appear from experiment that
in order for a perfon to be ſhocked, a communication *
with the floor is neceffary : for he that holds the bottle
with one hand, and touches the wire with the other, will

be ſhock'd as much, though his fhoes be dry, or even ftanding on wax, as otherwife. And on the touch of

the wire ( or of the gun -barrel, which is the fame thing) the fire does not proceed from the touching finger to the wire, as is fuppofed, but from the wire to the finger, and paffes through the body to the other hand, and ſo into the bottom of the bottle.

EXPERIMENTS Confirming the above.
EXPERIMENT I.
Place an electrifed phial on wax ; a fmall cork-ball fufpended by a dry filk-thread held in your hand, and
brought :.

16

New Experiments and

brought near to the wire, will first be attracted, and then

repelled when in this ftate of repellency, fink your

hand, that the ball may be brought towards the bottom of

the bottle ; it will be there inftantly and ftrongly attracted,

'till it has parted with its fire.

If the bottle had a poſitive electrical atmoſphere, as well

as the wire, an electrified cork would be repelled from one as well as from the other.

EXPERIMENT II.

FIG. 1. From a bent wire (a ) fticking in the table, let a ſmall linen thread (6) hang down within half an inch of

the electrifed phial (c) . Touch the wire of the phial re peatedly with your finger, and at every touch you will fee

the thread inftantly attracted by the bottle. (This is beft

done by a vinegar cruet, or fome fuch belly'd bottle . ) As

foon

as

you

draw

fire any

out

from the upper part,

by

touching the wire, the lower part of the bottle draws an

equal quantity in by the thread .

EXPERIMENT III .
F FIG. 2. Fix a wire in the lead , with which the bottom
i of the bottle is armed (d) ſo as that bending upwards, its
ring- end may be level with the top or ring-end of the wire
in the cork (e) , and at three or four inches diftance. Then
electriciſe the bottle, and place it on wax. If a cork fuf
pended by a filk thread (f) hang between theſe two wires,
it will play inceffantly from one to the other, ' till the bottle is

Obfervations on ELECTRICITY .

17

is no longer electrifed ; that is, it fetches and carries fire

from the top to the bottom ofthe bottle, ' till the equili brium is reſtored.

EXPERIMENT IV.
FIG. 3. Place an electrifed phial on wax ; take a wire (g) in form ofa C, the ends at ſuch a diſtance when bent, as that the upper may touch the wire of the bottle, when the lower touches the bottom : ftick the outer part on a ftick of fealing-wax (b), which will ferve as a handle ; then apply the lower end to the bottom of the bottle, and gradually bring the upper end near the wire in the cork . The confequence is, fpark follows fpark till the equilibrium is reſtored . Touch the top firſt, and on ap proaching the bottom with the other end, you have a con ftant ftream of fire from the wire entering the bottle. Touch the top and bottom together, and the equilibrium will inſtantly be reftored ; the crooked wire forming the communication .

EXPERIMENT V.

FIG. 4. Let a ring of thin lead, or paper, furround a bottle (i) even at ſome diſtance from or above the bottom. From that ring let a wire proceed up, till it touch the wire of the cork (k ). A bottle fo fixt cannot by any means be electrifed the equilibrium is never deftroyed : for

i. e. from the infide to the outfide. D

while

PRE

18

New Experiments and

while the communication between the upper and lower

parts of the bottle is continued by the outfide wire, the fire only circulates : what is driven out at bottom, is con

ſtantly ſupply'd from the top †. Hence a bottle cannot be electriſed that is foul or moift on the outſide, if ſuch moisture continue up to the cork or wire.

• EXPERIMENT VI.

Place a man on a cake of wax, and prefent him the wire of the electrified phial to touch, you ftanding on the floor, and holding it in your hand. As often as he touches it, he

will be electrified plus ; and any one ſtanding on the floor
" may draw a ſpark from him. The fire in this experiment

paffes out of the wire into him ; and at the fame time out

of your hand into the bottom of the bottle.

10

***..

EXPERIMENT VII.

"

Give him the electrical phial to hold ; and do you touch

the wire ; as often as you touch it he will be electrified minus, and may draw a fpark from any one ſtanding on

the floor. The fire now paffes from the wire to you, and from him into the bottom of the bottle.

EXPERIMENT VIII . Lay two books on two glaffes, back towards back, two or three inches diftant . Set the electrified phial on one, and then touch the wire ; that book will be electrified

* See the preceding note .

minus

Obfervations on ELECTRICITY.

19

minus the electrical fire being drawn out of it by the bot tom of the bottle. Take off the bottle, and holding it in your hand, touch the other with the wire ; that book will be electrifed plus ; the fire paffing into it from the wire, and the bottle at the fame time fupplied from your hand. A ſuſpended ſmall cork-ball will play between theſe books 'till the equilibrium is reſtored.

EXPERIMENT a

IX .

When a body is electrifed plus, it will repel an electrified feather or ſmall cork- ball. When minus (or when in the common ſtate ) it will attract them, but ſtronger when minus than when in the common ſtate, the difference being greater.

EXPERIMENT . X.

Though, as in Experiment VI. a man ſtanding on wax may be electrifed a number of times by repeatedly touching the wire of an electrifed bottle (held in the hand of one ftanding on the floor) he receiving the fire from the wirel each time yet holding it in his own hand, and touching the wire, though he draws a ſtrong ſpark, and is violently ſhocked, no Electricity remains in him ; the fire only paf fing through him, from the upper to the lower part of the bottle . Obferve, before the ſhock, to let fome one on the floor touch him to restore the equilibrium in his body ; for in taking hold of the bottom of the bottle, he ſome times becomes a little electrifed minus, which will continue

after the ſhock, as would alfo any plus Electricity, which

D2

he

20

New Experiments and

he might have given him before the ſhock. For, reftoring the equilibrium in the bottle, does not at all affect the E lectricity in the man through whom the fire paffes ; that Electricity is neither increaſed nor diminiſhed .

EXPERIMENT XI .

The paffing of the electrical fire from the upper to the lower part ofthe bottle, to reſtore the equilibrium, is ren dered ſtrongly viſible by the following pretty experiment. Take a book whoſe covering is filletted with gold ; bend a wire of eight or ten inches long, in the form of ( m) Fig. 5. flip it on the end of the cover of the book, over the gold line, ſo as that the ſhoulder of it may preſs upon one end of the gold line, the ring up, but leaning towards the other end of the book. Lay the book on a glaſs or wax, and on the other end of the gold lines fet the bottle elec trifed ; then bend the fpringing wire, by preffing it with a ſtick of wax till its ring approaches the ring of the bottle wire, inftantly there is a ſtrong ſpark and ſtroke, and the whole line of gold, which completes the communication, between the top and bottom ofthe bottle, will appear a vivid flame, like the ſharpeft lightning . The cloſer the contact between the ſhoulder of the wire, and the gold at i one end of the line, and between the bottom of the bottle and the gold at the other end, the better the experiment fucceeds. The room fhould be darkened . If you would

i.e.from the infide to the outfide.

have

A

Obfervations on ELECTRICITY .

21

have the whole filletting round the cover appear in fire at

once, let the bottle and wire touch the gold in the diaga

nally oppofite corners.

I am, &c.

B. FRANKLIN.

LETTER FROM

IV.

BENJ . FRANKLIN , Efq; in Philadelphia, TO
PETER COLLINSON, Efq; F. R. S. London.

Farther EXPERIMENTS and OBSERVATIONS in ELECTRICITY.

SIR,

1748.

§ I.

HERE will be the fame exploſion and ſhock

THif the electrified phial is held in one hand by

the hook, and the coating touch'd with the other, as when

held by the coating, and touch'd at the hook.

2. To

22

New Experiments and

2. To take the charg'd phial fafely by the hook, and not at the fame time diminish its force, it muſt firſt be ſet

down on an electric per fe. 3. The phial will be electrified as ftrongly, if held by
the hook, and the coating apply'd to the globe or tube ; as when held by the coating, and the hook apply'd * .
4. But the direction of the electrical fire being different in the charging, will alfo be different in the exploſion. The bottle charged through the hook, will be difcharged through the hook , the bottle charged through the coat ing, will be diſcharged through the coating, and not other † ways ; for the fire muſt come out the fame way it went in.
5. To prove this, take two bottles that were equally charged through the hooks, one in each hand : bring their hooks near each other, and no fpark or fhock will follow; becauſe each hook is diſpoſed to give fire, and neither to receive it. Set one of the bottles down on glaſs, take it up by the hook, and apply its coating to the hook of the other ; then there will be an exploſion and ſhock, and both bottles will be diſcharged.
6. Vary the experiment, by charging two phials equally, one through the hook, the other through the coating : hold that by the coating which was charged through the hook ; and that by the hook which was charged through the coating : apply the hook of the firſt to the coating of the

* This was a Diſcovery of the very ingenious Mr Kinnerfley's, and by

him communicated to me.

other,

I

T 1

Obfervations on ELECTRICITY.

23

other, and there will be no fhock or fpark . Set that down on glafs which you held by the hook, take it up by the coating, and bring the two hooks together : a ſpark and fhock will follow, and both phials be diſcharged.
In this experiment the bottles are totally difcharged, or the equilibrium within them reftored . The abounding of fire in one of the hooks (or rather in the internal furface of one bottle (being exactly equal to the wanting of the other : and therefore, as each bottle has in itſelf the abounding as well as the wanting, the wanting and abounding muſt be
But if a man equal in each bottle . See § . 8, 9, 10 , 11 . holds in his hands two bottles, one fully electrified, the other not at all, and brings their hooks together, he has but half a fhock, and the bottles will both remain half e lectrified, the one being half diſcharged, and the other half charged .
7. Place two phials equally charged on a table at five or fix inches diftance . Let a cork-ball, fufpended by a filk thread, hang between them . If the phials were both charged through their hooks, the cork, when it has been attracted and repelled by the one, will not be attracted, but equally repelled by the other. But if the phials were charged, the one through the hook, and the other through the coating, the ball, when it is repelled from one hook,

To charge a bottle commodioufly through the coating, place it on a glass ftand ; form a communication from the prime conductor to the coating, and another from the hook to the wall or floor. When it is charged, remove the latter communication before you take hold of the bottle, otherwife great part of the fire will efcape by it.
will

24

New Experiments and

be as ftrongly attracted by the other, and play vigorously between them , till both phials are nearly diſcharged.

8. When we uſe the terms of charging and diſcharging the phial, it is in compliance with cuſtom, and for want of others more ſuitable . Since we are of opinion that there is really no more electrical fire in the phial after what is

called its charging, than before, nor leſs after its diſcharging ; excepting only the ſmall ſpark that might be given to, and taken from the non - electric matter, if ſeparated from the bottle, which ſpark may not be equal to a five hun dredth part of what is called the explosion.
For if, on the exploſion , the electrical fire came out of the bottle by one part, and did not enter in again . by ano ther, then, ifa man, ſtanding on wax, and holding the bot tle in one hand, takes the ſpark by touching the wire hook with the other, the bottle being thereby discharged, the man would be charged ; or whatever fire was loft by one, would be found in the other, fince there was no way for

its efcape : But the contrary is true. 9. Befides, the phial will not fuffer what is called a
charging, unleſs as much fire can go out of it one way, as is thrown in by another. A phial cannot be charged ſtanding on wax or glafs, or hanging on the prime con ductor , unless a communication be formed between its
coating and the floor. 10. But fufpend two or more phials on the prime con
ductor, one hanging to the tail of the other ; and a wire from the laft to the floor, an equal number of turns ofthe
wheel

Obfervations on ELECTRICITY .

25

wheel ſhall charge them all equally, and every one as much as one alone would have been. What is driven out at the tail ofthe firſt, ſerving to charge the fecond ; what is driven out of the fecond charging the third ; and ſo on. By this means a great number of bottles might be charged with the fame labour, and equally high, with one alone , were it not that every bottle receives new fire, and loſes its old with ſome reluctance, or rather gives ſome ſmall re ſiſtance to the charging, which in a number of botttles be comes more equal to the charging power, and fo repels the fire back again on the globe, ſooner than a ſingle bottle would do .
II. When a bottle is charged in the common way, its infide and outſide ſurfaces ftand ready, the one to give fire by the hook, the other to receive it by the coating ; the one is full, and ready to throw out, the other empty and extremely hungry ; yet as the firſt will not give out, unleſs the other can at the fame inftant receive in ; fo neither will the latter receive in , unleſs the firſt can at the ſame inſtant give out. When both can be done at once, it is done with inconceivable quickneſs and violence.

12. So a ſtrait fpring (though the compariſon does not agree in every particular) when forcibly bent, muft, to re

ftore itſelf, contract that fide which in the bending was ex

tended, and extend that which was contracted ; if either of

theſe two operations be hindered, the other cannot be

done. But the fpring is not faid to be charg'd with elaſti

E

city

4TN.V

-26

New Experiments and

city when bent, and diſcharged when unbent ; its "quantity of elafticity is always the fame.
13. Glaſs, in like manner, has, within its fubftance, always the fame quantity of electrical fire, and that a very great quantity in proportion to the mafs of glafs, as ſhall be fhewn hereafter.

14. This quantity, proportioned to the glass, it ſtrongly and obftinately retains, and will have neither more nor leſs

though it will fuffer a change to be made in its parts and

fituation ; i. e. we may take away part of it from one

of the fides, provided we throw an equal quantity into the other.

15. Yet when the fituation of the electrical fire is thus

altered in the glafs ; when ſome has been taken from one fide, and fome added to the other, it will not be at reſt or in its natural ſtate, till it is restored to its original equality.

I

And this reftitution cannot be made through the ſubſtance

of the glaſs, but muſt be done by a non- electric communi

cation formed without, from furface to ſurface.

16. Thus, the whole force of the bottle, and power of

giving a fhock , is in the GLASS ITSELF ; the non-electrics in contact with the two furfaces, ferving only to give and

receive to and from the ſeveral parts ofthe glaſs ; that is, to give on one fide, and take away from the other.

17. This was diſcovered here in the following manner :

Purpofing to analyſe the electrified bottle, in order to find

wherein its ſtrength lay, we placed it on glafs , and drew

out the cork and wire which for that purpoſe had been loofe

Obfervations on ELECTRICITY .

27

loofely put in. Then taking the bottle in one hand, and bringing a finger of the other near its mouth, a ſtrong ſpark came from the water, and the ſhock was as violent as if the wire had remained in it, which fhewed that the force did not lie in the wire. Then to find if it refided in the water,

being crouded into and condenſed in it, as confin'd by the glafs, which had been our former opinion, we electrified the bottle again, and placing it on glaſs, drew out the wire and cork as before ; then taking up the bottle, we decanted all its water into an empty bottle, which likewiſe ſtood on glaſs ; and taking up that other bottle, we expected , if the force refided in the water, to find a fhock from it ; but there was none. We judged then that it muſt either be

loft in decanting , or remain in the first bottle. The latter we found to be true ; for that bottle on trial gave the ſhock, though filled up as it ftood with fresh unelectrified water from a tea-pot. - To find, then, whether glafs had this property merely as glafs, or whether the form contributed

any thing to it ; we took a pane of faſh-glaſs, and laying

it on the hand, placed a plate of lead on its upper ſurface ;

then electrified that plate, and bringing a finger to it, there was a ſpark and ſhock. We then took two plates of lead

of equal dimenſions , but lefs than the glass by two inches every way, and electrified the glafs between them , by

electrifying the uppermost lead ; then ſeparated the glaſs

from the lead, in doing which, what little fire might

be in the lead was taken out, and the glafs being touched

in the electrified parts with a finger, afforded only very

E2

fmall

1

28 New Experiments and
ſmall pricking ſparks, but a great number of them might be taken from different places. Then dexterously placing it again between the leaden plates, and compleating a circle between the two furfaces, a violent shock en fued.-M MAN Which demonftrated the power to refide in glaſs as glaſs, and that the non - electrics in contact ſerved only, like the armature of a loadſtone, to unite the force of the feveral parts, and bring them at once to any point defired : it being the property of a non- electric, that the whole body inſtantly receives or gives what electrical fire is given to or taken from any one of its parts.
18. Upon this we made what we called an electrical battery, confifting of eleven panes of large faſh- glaſs, arm'd with thin leaden plates, paſted on each fide, placed verti cally, and ſupported at two inches diſtance on filk cords, with thick hooks of leaden wire, one from each fide, ſtanding upright, diftant from each other, and convenient communications of wire and chain, from the giving fide of one pane, to the receiving fide of the other ; that fo the whole might be charged together, and with the fame la bour as one fingle pane ; and another contrivance to bring the giving fides, after charging, in contact with one long wire, and the receivers with another, which two long wires would give the force of all the plates of glaſs at once through the body of any animal forming the circle with them. The plates may alfo be diſcharged feparately, or any number together that is required . But this machine is not much uſed, as not perfectly anſwering our intention
with

Obfervations on ELECTRICITY.

29

with regard to the eaſe of charging, for the reaſon given, Sec. 10. We made alfo of large glass panes, magical pictures, and ſelf- moving animated wheels, prefently to be deſcribed .
19. I perceive by the ingenious Mr Watfon's laft book, lately received, that Dr Bevis had ufed, before we had, panes of glaſs to give a fhock ; though, till that book came to hand, I thought to have communicated it to you as a novelty. The excufe for mentioning it here is, that we tried the experiment differently, drew different confe quences from it (for Mr Watfon ftill feems to think the fire accumulated on the non- electric that is in contact with the glafs, page 72 ) and, as far as we hitherto know, have carri ed it farther.

20. The magical picture is made thus. Having a large metzotinto with a frame and glaſs, fuppofe of the KING, (God preſerve him ) take out the print, and cut a pannel out of it, near two inches diftant from the frame all round. If the cut is through the picture it is not the worſe. With thin paſte, or gum-water, fix the border that is cut off on the infide the glafs, preffing it fmooth and cloſe ; then fill up the vacancy by gilding the glass well with leaf gold, or brafs. Gild likewife the inner edge of the back of the frame all round, except the top part, and form a com munication between that gilding and the gilding behind

I have fince heard that Mr Smeaton was the firft who made ufe ofpanes of glaſs forthat purpoſe.
+ Contrived by Mr Kinnerfley. the

30

New Experiments and

the glass : then put in the board, and that fide is finiſhed . Turn up the glafs, and gild the fore fide exactly over the

back gilding, and when it is dry, cover it, by pafting on

the pannel of the picture that hath been cut out, obferving

to bring the correfpondent parts of the border and picture together, by which the picture will appear of a piece, as at

firſt, only part is behind the glaſs, and part before. - Hold the picture horizontally by the top, and place a little moveable gilt crown on the king's head. If now the pic ture be moderately electrified, and another perfon take hold of the frame with one hand, fo that his fingers touch its

infide gilding, and with the other hand endeavour to take off the crown, he will receive a terrible blow, and fail in the attempt. Ifthe picture were highly charged, the con

W

fequence might perhaps be as fatal * as that of high treaſon,

忄

for when the ſpark is taken through a quire of paper laid

on the picture, by means of a wire communication, it makes a fair hole through every ſheet, that is, through for

ty-eight leaves, (though a quire of paper is thought good

armour against the puſh of a fword, or even againſt a pif tol bullet, and the crack is exceeding loud. The operator,

who holds the picture by the upper end, where the infide of the frame is not gilt, to prevent its falling, feels nothing of the fhock, and may touch the face of the picture with

out danger, which he pretends is a teft of his loyalty. - Ifa

* We have fince found it fatal to fmall animals, though not to large

ones. The biggeſt we have yet killed is a hen.

1750.

ting

Obfervations on ELECTRICITY .

31

ring of perfons take the ſhock among them, the experi

ment is called, The Confpirators. 21. On the principle, in Sec. 7 , that hooks of bottles, dif

ferently charged, will attract and repel differently, is made

an electrical wheel, that turns with confiderable ftrength.

A fmall upright fhaft of wood paffes at right angles through a thin round board, of about twelve inches diameter, and turns on a ſharp point of iron, fixed in the lower end, while

a ſtrong wire in the upper end, paffing through a ſmall

hole in a thin brass plate, keeps the fhaft truly vertical .

About thirty radii of equal length, made of faſh-glaſs, cut in narrow ftrips, iffue horizontally from the circumference

of the board, the ends moft diftant from the center being a

bout four inches apart. On the end of every one, a braſs thimble is fixed. If now the wire of a bottle electrified in

the common way, be brought near the circumference of this wheel, it will attract the neareſt thimble, and fo put

the wheel in motion ; that thimble, in paffing by, receives

a ſpark, and thereby being electrified is repelled , and ſo dri
ven forwards ; while a fecond being attracted , approaches •
the wire, receives a fpark, and is driven after the firſt, and
fo on till the wheel has gone once round, when the thim

bles before electrified approaching the wire, inftead of be ing attracted as they were at firft, are repelled , and the mo tion preſently ceafes.-But if another bottle, which had been charged through the coating, be placed near the fame wheel, its wire will attract the thimble repelled by the firft, and thereby double the force that carries the wheel
round ;

32

New Experiments and

round ; and not only taking out the fire that had been communicated to the thimbles by the first bottle, but even

robbing them of their natural quantity, inſtead of being

repelled when they come again towards the firſt bottle, they are more ſtrongly attracted, fo that the wheel mends its

pace, till it goes with great rapidity twelve or fifteen rounds

in a minute, and with ſuch ſtrength, as that the weight of

one hundred Spanish dollars with which we once loaded it, did not feem in the leaſt to retard its motion . This is

called an electrical jack ; and if a large fowl were ſpitted on the upright ſhaft, it would be carried round before a fire with a motion fit for roafting.

22. But this wheel, like thofe driven by wind, water, or weights, moves by a foreign force, to wit, that of the bot : tles. The ſelf- moving wheel, though conſtructed on the fame principles, appears more furpriſing. 'Tis made of a thin round plate of window-glaſs, ſeventeen inches diame ter, well gilt on both fides, all but two inches next the

edge. Two fmall hemifpheres of wood are then fixed with cement to the middle of the upper and under fides, -centrally oppofite, and in each of them a thick ftrong wire - eight or ten inches long, which together make the axis of the wheel. It turns horizontally on a point at the lower end of its axis, which refts on a bit of brafs cemented within a glaſs falt- cellar. The upper end of its axis paffes through a hole in a thin braſs plate cemented to a long ſtrong piece of glaſs, which keeps it fix or eight inches dif tart from any non-electric, and has a ſmall ball of wax or
metal

Obfervations on ELECTRICITY .

33

metal on its top to keep in the fire. In a circle on the table which ſupports the wheel, are fixed twelve ſmall pil lars of glaſs, at about four inches diſtance, with a thimble on the top ofeach. On the edge of the wheel is a ſmall leaden bullet, communicating by a wire with the gilding of the upper furface of the wheel ; and about fix inches from it is another bullet communicating in like manner with the under ſurface. When the wheel is to be charged by the upper furface, a communication muſt be made from the under ſurface to the table. When it is well charged it be gins to move ; the bullet neareſt to a pillar moves towards the thimble on that pillar, and paffing by, electrifies it, and then puſhes itſelf from it ; the fucceeding bullet, which communicates with the other ſurface of the glafs, more ſtrongly attracts that thimble, on account of its being be fore electrified by the other bullet ; and thus the wheel en
creaſes its motion till it comes to fuch a height as that the reſiſtance of the air regulates it. It will go half an hour, and make one minute with another twenty turns in a mi nute, which is fix hundred turns in the whole ; the bul let of the upper furface giving in each turn twelve ſparks, to the thimbles , which makes feven thouſand two hun dred ſparks ; and the bullet of the under furface receiving as many from the thimbles ; thofe bullets moving in the time near two thousand five hundred feet -The thim bles are well fixed, and in fo exact a circle, that the bul lets may paſs within a very fmall diſtance of each of

them.-If instead of two bullets you put eight, four com

F

muni

34

New Experiments and

municating with the upper furface, and four with the un der furface, placed alternately ; which eight, at about fix

inches diſtance, completes the circumference, the force and ſwiftneſs will be greatly increaſed, the wheel making fifty

turns in a minute ; but then it will not continue moving

fo long.

Theſe wheels may be applied, perhaps, to the

ringing of chimes *, and moving of light- made orreries.

23. A fmall wire bent circularly, with a loop at each end ; let one end reft againſt the under furface of the

wheel, and bring the other end near the upper furface,

it will give a terrible crack, and the force will be dif charged .

24. Every fpark in that manner drawn from the furface 1 I
of the wheel, makes a round hole in the gilding, tearing
A
off a part of it in coming out ; which fhews that the fire

is not accumulated on the gilding, but is in the glafs itſelf.

25. The gilding being varniſhed over with turpentine varniſh, the varniſh, though dry and hard, is burnt by the
fpark drawn through it, and gives a ſtrong ſmell and viſible fmoke . And when the fpark is drawn through paper, all round the hole made by it, the paper will be blacked by
the ſmoke, which fometimes penetrates feveral of the leaves. #
Part of the gilding torn off, is alfo found forcibly driven into the hole made in the paper by the ſtroke.

This was afterwards done with fuccefs by Mr Kinnerfley. 26. It

Obfervations on ELECTRICITY .

35

26. It is amazing to obferve in how ſmall a portion of glass a great electrical force may lie. A thin glass bubble about an inch diameter, weighing only fix. grains, being half filled with water, partly gilt on the outfide, and fur niſh'd with a wire hook, gives, when electrified , ¿as great a fhock as a man can well bear. As the glafs is thickest near the orifice, I fuppofe the lower half, which being gilt was electrified and gave the fhock, did not exceed two grains ; for it appeared, when broke, much thinner than the upper half.-If one of theſe thin bottles be electrified

by the coating, and the ſpark taken out through the gilding, it will break the glafs inwards, at the fame time that it

breaks the gilding outwards. 27. And allowing (for the reafons before given, §. 8, 9,
10.) that there is no more electrical fire in a bottle after charging, than before, how great muſt be the quantity in this ſmall portion of glafs ! It feems as if it were of its very fubftance and effence. Perhaps if that due quantity of electrical fire ſo obftinately retained by glaſs, could be ſeparated from it, it would no longer be glaſs ; it might lofe its tranfparency, or its brittleness, or its elafticity. Experiments may poffibly be invented hereafter, to dif

cover this. 27. We were ſurpriſed at the account given in Mr Wat

fon's book, of a fhock communicated through a great ſpace of dry ground, and fufpect there must be fome metalline

quality in the gravel of that ground ; having found that

F2

fimple

C

B #

36

New Experiments and

fimple dry earth, rammed in a glafs tube, open at both ends, and a wire hook inferted in the earth at each end, the earth and wires making part of a circle, would not con

duct the leaſt perceptible fhock, and indeed when one
wire was electrified , the other hardly fhowed any figns of its being in connection with it * . Even a thoroughly " wet pack-thread ſometimes fails of conducting a ſhock,
though it otherwiſe conducts Electricity very well. A dry cake of ice, or an icicle held between two in a circle, like

wife prevents the ſhock , which one would not expect, as water conducts it fo perfectly well . -Gilding on a new book, though at firſt it conducts the ſhock extremely well, yet fails after ten or a dozen experiments, though it ap pears otherwiſe in all reſpects the fame, which we cannot account for +.

28. There is one experiment more which furprizes us, and is not hitherto fatisfactorily accounted for ; it is this Place an iron ſhot on a glaſs ſtand, and let a ball of damp cork, fufpended by a filk thread, hang in contact with the ſhot. Take a bottle in each hand, one that is electrified through the hook, the other through the coating : Apply the giving wire to the fhot, which will electrify it pofitive

* Probably the ground is never ſo dry.
+ We afterwards found that it failed after one ftroke with a large bot tle ; and the continuity of the gold appearing broken, and many of its parts diffipated, the Electricity could not pafs the remaining parts without leaping from part to part through the air, which always refifts the motion of this Auid, and was probably the cauſe of the gold's not conducting fo well as before.
by,

Obfervations on ELECTRICITY .

37

by, and the cork fhall be repelled : then apply the requiring wire, which will take out the ſpark given by the other ; when the cork will return to the ſhot : Apply the fame again, and take out another ſpark , fo will the ſhot be electrified negatively, and the cork in that cafe fhall be 1 repelled equally as before. Then apply the giving wire to the ſhot, and give the fpark it wanted, fo will the cork return : Give it another, which will be an addition to its natural quantity, ſo will the cork be repelled again : And fo may the experiment be repeated as long as there is any charge in the bottles. Which fhews that bodies having leſs than the common quantity of Electricity, repel each o · ther, as well as thoſe that have more .
Chagrined a little that we have been hitherto able to produce nothing in this way of uſe to mankind ; and the hot weather coming on, when electrical experiments are not fo agreeable, it is propoſed to put an end to them for this ſeaſon, ſomewhat humorously, in a party of pleaſure, on the banks of Skuylkil * . Spirits, at the fame time, are to be fired by a ſpark fent from fide to fide through the river, without any other conductor than the water ; an experiment which we fome time fince performed, to the amazement of many +. A turkey is to be killed for our
dinner

The river that waſhes one fide of Philadelphia, as the Delaware does the other ; both are ornamented with the fummer habitations of the citi zens, and the agreeable manfions of the principal people of this colony.
+ Asthe poffibility of this experiment has not been eaſily conceived, I fhall

3.8.

New Experiments and

dinner by the electrical shock, and roafted by the electrical

jack, before a fire kindled by the electrified bottle : when . the healths of all the famous electricians in England, Hol

land, France , and Germany, are to be drank in * electrified

bumpers, under the diſcharge of guns from the electrical battery.

fhall here defcribe it.-Two iron rods, about three feet long, were planted juft within the margin of the river, on the oppofite fides. A thick piece of wire, with a ſmall round knob at its end, was fixed to the top of one ofthe rods, bending downwards, fo as to deliver commodioufly the fpark upon the furface of the fpirit. A fmall wire faftened by one end to the handle of the fpoon, containing the fpirit, was carried a-cross the river, and ſupported in the air by the rope commonly uſed to hold by, in drawing the ferry-boats o
The other end of this wire was tied round the coating of the bottle ; which being charged, the ſpark was delivered from the hook to the top of the rod ftanding in the water on that fide. At the fame inſtant the rod on the other fide delivered aſpark into the ſpoon , and fired the fpirit. The electric fire returning to the coating of the bottle, through the handle of the ſpoon and the fupported wire connected with them..
That the electric fire thus actually paffes through the water, has fince been fatisfactorily demonftrated to many by an experiment of Mr Kinner fley's, performed in a trough of water about ten feet long. The hand being placed under water in the direction of the fpark (which always takes the trait or ſhorteſt courfe) is ftruck and penetrated by it as it paſſes.
* An electrified bumper is a ſmall thin glafs tumbler, near filled with wine, and electrified as the bottle. This when brought to the lips gives a fhock, ifthe party be cloſe ſhaved, and does not breathe on the liquor.

April 29, 1749 .

* LET

Obfervations on ELECTRICITY .

39

•

LETTER

V.

CONTAINING

OBSERVATIONS and SUPPOSITIONS, towards forming a new HYPOTHESIS , for ex plaining the feveral Phænomena of THUN DER -GUSTS *.

SIR,
ON- ELECTRIC bodies, that have electric fire §. 1.N
thrown into them, will retain it till other
non- electrics , that have lefs, approach ; and then it is com municated by a fnap, and becomes equally divided .
2. Electrical fire loves water, is ſtrongly attracted by it, and they can ſubſiſt together.
3. Air is an electric per fe, and when dry will not con duct the electrical fire ; it will neither receive it, nor give it to other bodies ; otherwife no body furrounded by air, could be electrified pofitively and negatively : for fhould it
* Thunder-gufts are fudden ftorms of thunder and lightning, which are frequently of fhort duration, but fometimes produce mifchievous effects.
be

40

New Experiments and

be attempted pofitively: the air would immediately take a way the overplus ; or negatively, the air would fupply what was wanting.
4 . Water being electrified, the vapours ariſing from it will be equally electrified ; and floating in the air, in the form of clouds, or otherwife, will retain that quantity of electrical fire, till they meet with other clouds or bodies not fo much electrified, and then will communicate as before mentioned.

5. Every particle of matter electrified is repelled by every other particle equally electrified . Thus the ſtream of a fountain, naturally denfe and continual, when electri fied, will ſeparate and ſpread in the form of a bruſh, every drop endeavouring to recede from every other drop. But on taking out the electrical fire they cloſe again.
6. Water being ftrongly electrified ( as well as when heated by common fire ) rifes in vapours more copiouſly ; the attraction of coheſion among its particles being greatly weakened, by the oppofite power of repulfion introduced with the electrical fire ; and when any particle is by any means difengaged, it is immediately repelled, and fo flies into the air.
7. Particles happening to be fituated as A and B, (FIG. VI. repreſenting the profile of a vessel of water) are more eafily difengaged than C and D, as each is held by contact with three only, whereas C and D are each in contact with nine. When the furface of the water has the leaſt motion ,
parti

Obfervations on ELECTRICITY.

41

particles are continually puſhed into the fituation reprefent ed by A and B.
8. Friction between a non- electric and an electric per fe will produce electrical fire ; not by creating, but collecting it for it is equally diffuſed in our walls, floors, earth , and the whole mafs of common matter. Thus the whirling

glafs globe, during its friction against the cushion , draws fire from the cushion, the cushion is fupplied from the frame of the machine, that from the floor on which it ftands . Cut off the communication by thick glass or wax,

‫ތ‬

placed under the cuſhion , and no fire can be produced, be cauſe it cannot be collected.

9. The ocean is a compound of water, a non- electric,

and ſalt an electric per ſe. 10. When there is a friction among the parts near its
furface, the electrical fire is collected from the parts below. It is then plainly vifible in the night ; it appears at the ftern and in the wake of every failing veffel ; every dafh

of an oar fhews it, and every furf and ſpray : In ftorms the
whole ſea ſeems on fire. The detach'd particles of water

then repelled from the electrified furface, continually carry

off the fire as it is collected ; they rife and form clouds,

and thoſe clouds are highly electrified, and retain the fire

till they have an opportunity of communicating it.

11. The particles of water rifing in vapours, attach them

felves to particles of air.

12. The particles of air are faid to be hard, round , fepa rate and diftant from each other ; every particle ftrongly

G

repelling

4.2

New Experiments and

repelling every other particle, whereby they recede from each other, as far as common gravity will permit.
13. The space between any three particles equally re pelling each other, will be an equilateral triangle.
14. In air compreffed , theſe triangles are ſmaller ; in ra rified air they are larger.

15. Common fire joined with air, increaſes the repul fion, enlarges the triangles, and thereby makes the air fpe cifically lighter. Such air, among denfer air, will rife.

16. Common fire, as well as electrical fire, gives repul fion to the particles of water, and destroys their attraction of coheſion ; hence common fire, as well as electrical fire, affifts in raifing vapours.

17. Particles of water, having no fire in them, mutually attract each other. Three particles of water then being attached to the three particles of a triangle of air, would by their mutual attraction operating againſt the air's repulfion, fhorten the fides and leffen the triangle, whereby that

portion of air being made denfer, would fink to the earth with its water, and not rife to contribute to the formation of a cloud.
18. But if every particle of water attaching itſelf to air, brings with it a particle of common fire, the repulfion of the air being affifted and ſtrengthened by the fire, more than obſtructed by the mutual attraction of the particles of water, the triangle dilates, and that portion of air becoming rarer and fpecifically lighter rifes.
19. If the particles of water bring electrical fire when

they

Obfervations on ELECTRICITY.

43

they attach themſelves to air, the repulfion between the particles of water electrified, joins with the natural repul fion of the air, to force its particles to a greater diftance,

whereby the triangles are dilated, and the air rifes, carrying up with it the water.
20. If the particles of water bring with them portions ofboth forts of fire, the repulfion of the particles of air is ſtill more ſtrengthened and increaſed , and the triangles far ther enlarged.

21. One particle of air may be furrounded by twelve particles of water of equal fize with itſelf, all in contact with it ; and by more added to thoſe.
22. Particles of air thus loaded would be drawn nearer

together bythe mutual attraction of the particles of water, did not the fire, common or electrical, affift their re pulfion.
23. If air thus loaded be compreffed by adverfe winds, or by being driven againſt mountains, &c. or condenſed
1 by taking away the fire that affifted it in expanding ; the triangles contract, the air with its water will defcend as a

dew ; or, if the water ſurrounding one particle of air comes in contact with the water furrounding another, they coa

lefce and form a drop, and we have rain .

24. The fun fupplies (or feems to ſupply) common fire to all vapours, whether raiſed from earth or ſea.
25. Thofe vvaappoouurrss which have both common and elec

trical fire in them, are better fupported, than thoſe which

have only common fire in them, For when vapours riſe

G2

into

44

New Experiments and ·

into the coldest region above the earth, the cold will not diminish the electrical fire , if it doth the common .

26. Hence clouds formed by vapours raiſed from freſh waters within land, from growing vegetables, moift earth, &c. more ſpeedily and eafily depofite their water, having but little electrical fire to repel and keep the particles fe parate . So that the greatest part of the water raiſed from the land, is let fall on the land again ; and winds blowing from the land to the fea are dry ; there being little uſe for rain on the fea, and to rob the land of its moiſture , in order to rain on the fea, would not appear reaſonable.
27. But clouds formed by vapours raiſed from the ſea, having both fires, and particularly a great quantity of the electrical, fupport their water ftrongly, raife it high, and being moved by winds, may bring it over the middle of the broadeft continent from the middle of the wideft ocean.
28. Howtheſe ocean clouds, fo ftrongly fupporting their water, are made to depofite it on the land where it is want ed, is next to be confidered.

29. If they are driven by winds againſt mountains, thoſe mountains being lefs electrified attract them, and on contact take away their electrical fire ( and being cold, the

common fire alfo ; ) hence the particles clofe towards the mountains and towards each other. If the air was not much loaded, it only falls in dews on the mountain tops and fides, forms fprings, and defcends to the vales in rivu lets, which united , make larger streams and rivers. If much loaded, the electrical fire is, at once taken from the
whole

W lo fir
ar in f
2

24

Obfervations on ELECTRICITY .

45

whole cloud ; and , in leaving it, flashes brightly and cracks loudly ; the particles inftantly coalefcing for want of that fire, and falling in a heavy ſhower .
30. When a ridge of mountains thus dams the clouds, and draws the electrical fire from the cloud first approach ing it ; that which next follows, when it comes near the first cloud, now deprived of its fire , flaſhes into it, and be gins to depofite its own water ; the firſt cloud again flaſh ing into the mountains ; the third approaching cloud, and all the fucceeding ones, acting in the fame manner as far back as they extend, which may be over many hundred miles of country.

31. Hence the continual ftorms of rain , thunder, and lightning on the eaft fide of the Andes, which running north and fouth, and being vaftly high, intercept all the clouds brought againſt them from the Atlantic ocean by the trade winds, and oblige them to depofite their waters,

by which the vast rivers Amazons, La Plata, and Oroonoko are formed, which return the water into the fame fea, after having fertilized a country of very great extent. " 32.. If a country be plain, having no mountains to inter cept the electrified clouds, yet it is not without means to make them depofite their water. For if an electrified cloud coming from the fea, meets in the air a cloud raiſed from the land, and3 therefore not electrified ; the first will flaſh its fire into the latter, and thereby both clouds fhall be made fuddenly to depofite water.
33. The electrified particles of the first cloud clofe when they fofe their fire ; the particles of the other cloud
clofe

46

New Experiments and

cloſe in receiving it : in both, they have thereby an oppor

tunity of coalefcing into drops. -The concuffion or jerk

given to the air, contributes alfo to ſhake down the water, not only from thofe two clouds, but from others near them. Hence the fudden fall of rain immediately after flaſhes of

lightning. 34. To fhew this by an eafy experiment : Take two
round pieces of paſteboard two inches diameter ; from the center and circumference of each of them fufpend by fine filk threads eighteen inches long, ſeven ſmall balls of wood, or feven peas equal in bignefs : fo will the balls ap

pending to each paſteboard, form equal equilateral trian gles, one ball being in the center, and fix at equal diſtances from that, and from each other ; and thus they repreſent particles ofair. Dip both fets in water, and fome adhering to each ball, they will reprefent air loaded. Dexterously

electrify one ſet, and its balls will repel each other to a greater diſtance, enlarging the triangles. Could the water fupported by the ſeven balls come into contact, it would form a drop or drops fo heavy as to break the coheſion it had with the balls, and ſo fall. Let the two fets then repreſent two clouds, the one a fea cloud electrified,

the other a land cloud. Bring them within the fphere of attraction, and they will draw towards each other, and you will fee the feparated balls clofe thus ; the firft

electrified ball that comes near an unelectrified ball by attraction joins it, and gives it fire ; inftantly they fepa rate, and each flies to another ball of its own party, one to

give

Obfervations on ELECTRICITY.

47

give, the other to receive fire ; and fo it proceeds through both fets, but fo quick as to be in a manner inftantaneous. In the collifion they shake off and drop their water, which repreſents rain.
35. Thus when fea and land clouds would pafs at too great a diſtance from the flash, they are attracted towards each other till within that diſtance ; for the ſphere of e lectrical attraction is far beyond the diſtance of flashing.
36. When a great number of clouds from the fea meet a number of clouds raiſed from the land, the electrical flaſhes appear to strike in different parts ; and as the clouds are jostled and mixed by the winds, or brought near by the electrical attraction, they continue to give and receive flaſh after flaſh , till the electrical fire is equally diffuſed .
37. When the gun - barrel ( in electrical experiments) has but little electrical fire in it, you muſt approach it very near with your knuckle, before you can draw a fpark. Give it more fire, and it will give a ſpark at a greater dif tance. Two gun-barrels united, and as highly electrified, will give a fpark at a ftill greater diftance. But if two gun-barrels electrified will ſtrike at two inches diſtance, and make a loud fnap, to what a great diſtance may 10,000 acres of electrified cloud ftrike and give its fire, and how loud muſt be that crack ?

38. It is a common thing to fee clouds at different heights paffing different ways, which fhews different cur rents of air, one under the other. As the air between the
tropics

8 4

w e N

Experiments

d n a

tropics is rarified by the fun , it rifes, the denfer northern and fouthern air preffing into its place. The air fo rari fied and forced up , paffes northward and fouthward, and muft defcend in the polar regions, if it has no opportunity before, that the circulation may be carried on .
39. As currents of air, with the clouds therein , pafs dif ferent ways, ' tis eaſy to conceive how the clouds, paffing over each other, may attract each other, and fo come near enough for the electrical ftroke. And alfo how electrical clouds may be carried within land very far from the fea,

before they have an opportunity to ſtrike .

40. When the air, with its vapours raiſed from the ocean between the tropics, comes to defcend in the polar regions, and to be in contact with the vapours arifing there, the electrical fire they brought begins to be com municated , and is feen in clear nights, being firſt viſible where ' tis firft in motion, that is, where the contact be

gins, or in the moft northern part ; from thence the ftreams of light feem to fhoot foutherly, even up to the zenith of northern countries. But tho ' the light feems to fhoot from the north foutherly, the progrefs of the fire is really from the fouth northerly, its motion beginning in the north being the reafon that ' tis there firſt ſeen .
For the electrical fire is never vifible but when in mo

tion, and leaping from body to body, or from particle to particle thro' the air. When it paffes thro' denfe bodies ' tis unfeen. When a wire makes part of the circle , in the exploſion of the electrical phial, the fire, though in great
quantity

Obfervations on ELECTRICITY.

49

quantity, paffes in the wire invifibly : but in paffing along a chain, it becomes viſible as it leaps from link to link. In paffing along leaf gilding ' tis vifible : for the leaf-gold , is
like a full of pores ; hold a leaf to the light and it appears net, and the fire is feen in its leaping over the vacancies. And as when a long canal filled with ſtill water is opened at one end, in order to be diſcharged, the motion of the
water begins firſt near the opened end, and proceeds to wards the cloſe end, tho' the water itſelf moves from the cloſe towards the opened end : ſo the electrical fire dif charged into the polar regions, perhaps from athouſand leagues length of vaporiſed air, appears firft where ' tis firſt in motion, i . e. in the moſt northern part, and the appear ance proceeds fouthward, tho' the fire really moves north ward. This is fuppofed to account for the Aurora Bo realis.
41 . When there is great heat on the land, in a particu lar region (the fun having fhone on it perhaps feveral days, while the ſurrounding countries have been ſcreen'd by clouds ) the lower air is rarified and riſes, the cooler denfer air above defcends ; the clouds in that air meet

from all fides, and join over the heated place ; and if ſome are electrified, others not, lightning and thunder fucceed , and ſhowers fall. Hence thunder-gufts after heats, and

cool air after gufts ; the water and the clouds that bring it, coming from a higher and therefore a cooler region.
42. An electrical fpark, drawn from an irregular body

at fome diſtance is fcarce ever ftrait, but fhows crooked

H

and

50

New Experiments and

and waving in the air. So do the flashes of lightning ; the

clouds being very irregular bodies. fm
43. As electrified clouds paſs over a country, high hills

‫ےہ‬

and high trees, lofty towers, fpires, maſts of ſhips, chim-. be
neys, &c. as fo many prominencies and points, draw the electrical fire, and the whole cloud difcharges there.

44. Dangerous, therefore, is it to take ſhelter under a

t

tree, during a thunder-guft. It has been fatal to many, both men and beaſts.

45. It is fafer to be in the open field for another reafon . When the cloaths are wet, if a flafh in its way to the

ground fhould ftrike your head, it may run in the water over the ſurface of your body ; whereas, if your cloaths were dry, it would go through the body...
Hence a wet rat cannot be killed by the exploding elec trical bottle, when a dry rat may *.
46. Common fire is in all bodies, more or lefs, as well as electrical fire. Perhaps they may be different modifi cations of the fame element ; or they may be different ele

ments. The latter is by fome fufpected .. 47. If they are different things, yet they may and do ,
ſubſiſt together in the ſame body. 48. When electrical fire ftrikes through a body, it acts .
upon the common fire contained in it, and puts that fire in motion ; and if there be a fufficient quantity of each kind of fire, the body will be inflamed.

This was tried with a bottle, containing about a quart. It is fince thought that one of the large glass jars, mentioned in theſe papers, might have killed him , though wet.
49: When :

Obfervations on ELECTRICITY .

51

49. When the quantity of common fire in the body is fmall, the quantity of the electrical fire ( or the electrical

ftroke) ſhould be greater : if the quantity of common fire be great, leſs electrical fire fuffices to produce the effect.
50. Thus fpirits muſt be heated before we can fire them by the electrical ſpark*. If they are much heated, a ſmall

fpark will do , if not, the ſpark muſt be greater. 51. 'Till lately we could only fire warm vapours ; but
now we can burn hard dry rofin. And when we can pro cure greater electrical ſparks, we may be able to fire not only unwarm'd fpirits, as lightning does, but even wood, by giving fufficient agitation to the common fire contained in it, as friction we know will do.

52. Sulphureous and inflammable vapours ariſing from the earth, are eaſily kindled by lightning. Befides what

ariſe from the earth, fuch vapours are ſent out by ſtacks of moift hay, corn, or other vegetables, which heat and reek.

Wood rotting in old trees or buildings does the fame. Such are therefore eafily and often fired.

53. Metals are often melted by lightning, tho ' perhaps
not from heat in the lightning, nor altogether from agi -
tated fire in the metals. For as whatever body can infi
nuate itſelf between the particles of metal, and overcome
the attraction by which they cohere (as fundry menſtrua

* Wehave fince fired fpirits without heating them, when the weather is warm. ** A little poured into the palm of the hand, will be warmed fuffi

ciently by the hand, if the ſpirit be well rectified. Æther takes fire moft

readily.

H2

can) .

52

New Experiments in ELECTRICITY.

can ) will make the folid become a fluid, as well as fire, yet without heating it : ſo the electrical fire, or lightning, creating a violent repulfion between the particles of the metal it paffes through, the metal is fufed.
54. Ifyou would, by a violent fire, melt off the end of a nail , which is half driven into a door, the heat given the

whole nail before a part would melt, muſt burn the board

it ſticks in . And the melted part would burn the floor it

dropp'd on. But ifa fword can be melted in the fcabbard,"

T

e and money in a man's pocket, by lightning, without burn

ing either, it muſt be a cold fufion *.

b

55. Lightning rends fome bodies. The electrical ſpark will ftrike a hole through a quire of ſtrong paper.

56. If the fource of lightning, affigned in this paper, be the true one, there fhould be little thunder heard at feat far from land. And accordingly fome old fea-captains, of whom enquiry has been made, do affirm, that the fact a grees perfectly with the hypothefis ; for that in croffing the great ocean, they feldom meet with thunder till they

come into foundings ; and that the islands far from the continent have very little of it. And a curious obferver,

who lived 13 years at Bermudas, fays, there was lefs thun der there in that whole time than he has fometimes heard in a month at Carolina.

* Thefe facts, though related in feveral accounts, are now doubted ; fince it has been obferved that the parts of a bell-wire which fell on the floor being broken and partly melted by lightning, did actually burn into the boards. (See Philof. Tranf. Vol . LI. Part I. and Mr Kinnerfley has found that a fine iron wire, melted by Electricity, has had the fame effect.)
AD

ADDITIONAL PAPERS то
PETER COLLINSON, Efq; F.R.S. London.

SIR,

Philadelphia, July 29 , 1750.

you first put us on electrical experiments, by As fending to our library company a tube, with di

rections how to uſe it ; and as our honourable proprietary enabled us to carry thoſe experiments to a greater height, by his generous prefent of a compleat electrical appara tus ; ' tis fit that both fhould know, from time to time, what progreſs we make. It was in this view I wrote and ſent you my former papers on this fubject, defiring, that

as I had not the honour of a direct correfpondence with that bountiful benefactor to our library, they might be. communicated to him through your hands. In the fame

view I write and fend you this additional paper. If it happens to bring you nothing new (which may well be, confidering the number of ingenious men in Europe, con tinually engaged in the fame reſearches) at leaſt it will

fhow, that the inftruments put into our hands are not ne glected ; and, that if no valuable diſcoveries are made by us, whatever the cauſe may be, it is not want of induſtry

and application.

I am, Sir, Your muchobliged Humble Servant,

B. FRANKLIN.

54

New Experiments and

ele fro eff

pli

OPINIONS and CONJECTURES,

W

14

concerning the Properties and Effects of the electrical Matter, arifing from Experiments and Obfervations, made at Philadelphia , 1749 .

§S.. 1.

HE electrical matter confifts of particles ex

ΤΗtremely fubtile, fince it can permeate com

mon matter, even the denfeft metals, with fuch eaſe and

freedom as not to receive any perceptible refiftance. 2. If any one ſhould doubt whether the electrical mat
ter paffes thro' the ſubſtance of bodies, or only over and along their furfaces, a fhock from an electrified large glaſs jar, taken through his own body, will probably convince him.

• 3. Electrical matter differs from common matter in this,'

that the parts of the latter mutually attract, thofe of the former mutually repel, each other. Hence the appearing divergency in a stream of electrified effluvia.

4. But though the particles of electrical matter do re •
pel each other, they are strongly attracted by all other
matter *.

See the ingenious effays on Electricity, in the Tranſactions, by Mr Ellicot
5. From

Obfervations on ELECTRICITY.

$55

5. From thefe three things, the extreme fubtilty of the electrical matter, the mutual repulfion of its parts, and the ftrong attraction between them and other matter, ariſe this effect , that, when a quantity of electrical matter is ap plied to a mass of common matter, ofany bignefs or length, within our obfervation (which hath not already got its
quantity) it is immediately and equally diffuſed through. the whole.
• 6. Thus common matter is a kind of fpunge to the
electrical fluid. And as a fpunge would receive no water if the parts of water were not ſmaller than the pores of the ſpunge ; and even then but flowly, if there were not a mutual attraction between thofe parts and the parts

of the fpunge ; and would ſtill imbibe it faſter, if the mutual attraction among the parts of the water did not impede , fome force being required to ſeparate them ; and fafteft, if, inſtead of attraction, there were a mutual repul fion among thofe parts, which would act in conjunction with the attraction of the fpunge. So is the cafe between 3 the electrical and common matter.
7. But in common matter there is (generally) as much of the electrical as it will contain within its fubftance . If

more is added, it lies without upon the furface, and form's what we call an electrical atmoſphere ; and then the body is faid to be electrified..

8. ' Tis fuppofed, that all kinds of common matter do
not attract and retain the electrical, with equal ſtrength and
force, for reasons to be given hereafter. And that thofe :.
called :

56

New Experiments and

called electrics per fe, as glafs, & c. attract and retain it ſtrongeſt, and contain the greateſt quantity.
9. We know that the electrical fluid is in common

matter, becauſe we can pump it out by the globe or tube. We know that common matter has near as much as it can contain, becauſe, when we add a little more to any por tion of it, the additional quantity does not enter, but forms an electrical atmoſphere . And we know that common matter has not (generally) more than it can contain, other wife all looſe portions of it would repel each other, as they conſtantly do when they have electric atmoſpheres.
10. The beneficial ufes of this electric fluid in the

creation, we are not yet well acquainted with, though doubtless fuch there are, and thoſe very confiderable ; but we may ſee ſome pernicious confequences that would at tend a much greater proportion of it. For had this globe we live on, as much of it in proportion as we can give to a globe of iron, wood, or the like, the particles of duft and other light matters that get looſe from it, would, by virtue of their ſeparate electrical atmoſpheres , not only repel each other, but be repelled from the earth, and not eafily be brought to unite with it again ; whence our air would continually be more and more clogged with foreign mat ter, and grow unfit for refpiration. This affords another occafion of adoring that wiſdom which has made all things by weight and meaſure !
11. If a piece of common matter be ſuppoſed entirely free from electrical matter, and a fingle particle of the
latter

Obfervations on ELECTRICITY.

57

latter be brought nigh, it will be attracted, and enter the

body, and take place in the center, or where the attraction
· is every way equal. If more particles enter, they take

their places where the balance is equal between the at traction of the common matter, and their own mutual re

pulfion . ' Tis fuppofed they form triangles, whofe fides ſhorten as their number increafes ; ' till the common mat ter has drawn in fo many, that its whole power of com

preffing thoſe triangles by attraction, is equal to their whole power of expanding themſelves by repulfion ; and then

will fuch piece of matter receive no more. 12. When part of this natural proportion of electrical

fluid is taken out of a piece of common matter, the trian gles formed by the remainder, are fuppofed to widen by the mutual repulfion of the parts, until they occupy the whole piece.

13. When the quantity of electrical fluid , taken from a piece of common matter, is reſtored again, it enters, the

expanded triangles being again compreffed till there is room for the whole.

14. To explain this : take two apples, or two balls of

wood or other matter, each having its own natural quantity

of the electrical fluid . Sufpend them by filk lines from the cieling. Apply the wire of a well- charged vial, held in your hand, to one of them (A) Fig. 7, and it will receive

from the wire a quantity of the electrical fluid ; but will not imbibe it, being already full. The fluid therefore will

flow round its furface, and form an electrical atmoſphere.

I

Bring

58

New Experiments and

Bring A into contact with B, and half the electrical fluid is communicated, fo that each has now an electrical at moſphere, and therefore they repel each other. Take away theſe atmoſpheres by touching the balls, and leave them in their natural ftate : then, having fixed a ſtick of fealing-wax to the middle of the vial to hold it by, apply the wire to A, at the fame time the coating touches B. Thus will a quantity of the electrical fluid be drawn out of B, and thrown on A. So that A will have a redun dance of this fluid, which forms an atmoſphere round it, and B an exactly equal deficiency . Now, bring theſe balls again into contact, and the electrical atmoſphere will not be divided between A and B, into two ſmaller atmoſpheres as before ; for B will drink up the whole at moſphere of A, and both will be found again in their na tural ſtate.

15. The form of the electrical atmoſphere is that of the body it furrounds. This fhape may be rendered vifible in a ſtill air, by raifing a ſmoke from dry rofin, dropt into a hot tea-fpoon under the electrifed body, which will be attracted, and ſpread itſelf equally on all fides, covering and concealing the body . And this form it takes, be cauſe it is attracted by all parts of the furface of the body; though it cannot enter the fubftance already replete. Without this attraction , it would not remain round the bo dy, but diffipate in the air.

* See fa_@ 6,

16. The

Obfervations on ELECTRICITY .

59

16. The atmoſphere of electrical particles furrounding an electrified ſphere, is not more difpofed to leave it, or more eaſily drawn off from any one part of the ſphere than from another, becauſe it is equally attracted by every part. But that is not the cafe with bodies of any other figure . From a cube it is more eaſily drawn at the corners than at the plane fides, and fo from the angles of a body of any other form, and ftill moſt eafily from the angle that is moſt acute. Thus if a body ſhaped as A,B,C, D,E, in Fig. 8 . be electrified, or have an electrical atmoſphere communi cated to it, and we confider every fide as a bafe on which the particles reft, and by which they are attracted , one may fee, by imagining a line from A to F, and another

from E to G, that the portion of the atmoſphere included

in F, A,E,G, has the line A E for its bafis. So the por tion of atmoſphere included in H, A, B, I , has the line

A, B, for its bafis. And likewife the portion included in K, B, C, L, has B, C, to reft on ; and fo on the

other fide of the figure. Now if you would draw off this atmoſphere with any blunt fmooth body, and ap proach the middle of the fide A, B, you must come

very near, before the force of your attracter exceeds the force or power with which that fide holds its atmoſphere. But there is a ſmall portion between 1, B, K, that has lefs of the ſurface to reft on , and to be attracted by, than the neigh

bouring portions, while at the fame time there is a mutual

repulfion between its particles, and the particles of thoſe

portions, therefore here you can get it with more eaſe, or at

I2

a great

-60

New Experiments and

a greater diſtance. Between F, A, H, there is a larger por as
tion that has yet a lefs furface to reft on, and to attract it ; th
here therefore you can get it away ftill more eafily. But el
eaſieſt of all between L, C, M, where the quantity is largeſt, Or
and the furface to attract and keep it back the leaſt. 0
When you have drawn away one of thefe angular portions fi
of the fluid, another fucceeds in its place, from the na→ C
ture of fluidity and the mutual repulfion before -mentioned ;
and fo the atmoſphere continues flowing off at fuch angle,
like a ſtream, till no more is remaining. The extremities
of the portions of atmoſphere over theſe angular parts, are
likewiſe at a greater diftance from the electrified body, as
may be ſeen by the infpection of the above figure ; the
point of the atmoſphere of the angle C, being much far
ther from C, than any other part of the atmoſphere over
the lines C, B, or B, A : And , befides the diftance arifing

from the nature of the figure, where the attraction is leſs, the particles will naturally expand to a greater diſtance by their mutual repulfion. On thefe accounts we fuppofe e lectrified bodies diſcharge their atmoſpheres upon unelec

trified bodies more eafily, and at a greater diſtance from their angles and points than from their ſmooth fides. — Thoſe points will alſo diſcharge into the air, when the bo dy has too great an electrical atmoſphere, without bring ing any non-electric near, to receive what is thrown off :

For the air, though an electric per fe, yet has always more or less water and other non -electric matters mixed with it :
and thefe attract and receive what is fo difcharged. 17. But

Obfervations on ELECTRICITY.

61

17. But points have a property, by which they draw on as well as throw off the electrical fluid, at greater diſtances than blunt bodies can . That is, as the pointed part of an

electrified body will diſcharge the atmoſphere of that body, or communicate it fartheft to another body, fo the point of an unelectrified body will draw off the electrical atmo

ſphere from an electrified body, farther than a blunter part of the fame unelectrified body will do . Thus a pin held by the head, and the point prefented to an electrified body, will draw off its atmoſphere at a foot diſtance ; where , if the head were prefented inftead of the point, no fuch effect would follow. To underſtand this, we may confider, that if a perfon ftanding on the floor would draw off the

electrical atmoſphere from an electrified body, an iron crow and a blunt knitting-needle held alternately in his hand, and preſented for that purpoſe, do not draw with different forces in proportion to their different maſſes. For the man, and what he holds in his hand, be it large
.1 or fmall, are connected with the common mafs of un electrified matter ; and the force with which he draws is

the fame in both cafes, it confifting in the different pro portion of electricity in the electrified body, and that com mon maſs. But the force with which the electrified body retains its atmoſphere by attracting it, is proportioned to the furface over which the particles are placed ; i. e. four

ſquare inches of that ſurface retain their atmoſphere with four times the force that one fquare inch retains its at moſphere. And as in plucking the hairs from the horse's
tail,

**
1 L

62

New Experiments and

tail, a degree of ſtrength not fufficient to pull away a handful at once, could yet eaſily ſtrip it hair by hair ; fo a blunt

body preſented cannot draw off a number of particles at once, but a pointed one, with no greater force, takes them

away eafily, particle by particle. 18. Theſe explanations of the power and operation of
points, when they first occurr'd to me, and while they first floated in my mind, appeared perfectly fatisfactory ; but now I have wrote them, and confidered them more cloſely in black and white, I muft own I have fome doubts about them ; yet, as I have at preſent nothing bet ter to offer in their ftead, I do not cross them out for even a bad folution read, and its faults difcovered, has of ten given riſe to a good one, in the mind of an ingenious reader.
19. Nor is it of much importance to us, to know the manner in which nature executes her laws ; ' tis enough if we know the laws themfelves. 'Tis of real ufe to know

that china left in the air unfupported will fall and break ; but how it comes to fall, and why it breaks, are matters of fpeculation. ' Tis a pleaſure indeed to know them , but we can preſerve our china without it.
20. Thus in the prefent cafe, to know this power of points, may poffibly be of fome ufe to mankind, though we ſhould never be able to explain it. The following experiments, as well as thofe in my first paper, fhew this

power. I have a large prime conductor, made of feveral thin ſheets of clothier's pafteboard, form'd into a tube, near
ten

Obfervations on ELECTRICITY .

63

ten feet long and a foot diameter. It is cover'd with

Dutch embols'd paper, almoft totally gilt. This large metallic furface ſupports a much greater electrical atmo

fphere than a rod of iron of 50 times the weight would

do. It is fufpended by filk lines, and when charged will ftrike at near two inches diftance, a pretty hard ſtroke, fo as to make ones knuckle ach . Let a perfon ftanding

on the floor preſent the point of a needle at 12 or more inches diſtance from it, and while the needle is fo pre

fented, the conductor cannot be charged, the point draw ing off the fire as faſt as it is thrown on by the electrical

globe. Let it be charged, and then preſent the point at the fame distance, and it will fuddenly be difcharged. In the dark you may fee a light on the point, when the ex

periment is made. And if the perfon holding the point ſtands upon wax, he will be electrified by receiving the

fire at that diſtance. Attempt to draw off the electricity with a blunt body, as a bolt of iron round at the end, and

fmooth ( a filversmith's iron punch, inch thick , is what I uſe ) and you, muft bring it within the diſtance of three inches before you can do it, and then it is done with a,

ftroke and crack. As the pafteboard tube hangs looſe on

filk lines, when you approach it with the punch iron, it

3

1

likewife will move towards the punch, being attracted

while it is charged ; but if, at the fame inftant, a point

be prefented as before, it retires again, for the point dif

charges it. Take a pair of large brais fcales, of two or: more feet beam, the cords of the fcales being filk . Suf
pend

64

New Experiments and

pend the beam by a pack-thread from the cieling, fo that

I

the bottom of the fcales may be about a foot from the

tv

floor : The fcales will move round in a circle by the un

ha

twifting of the packthread. Set the iron punch on the

at

end upon the floor, in ſuch a place as that the ſcales may

paſs over it in making their circle : Then electrify one

t

fcale, by applying the wire of a charged phial to it. As

they move round, you fee that ſcale draw nigher to the €
floor, and dip more when it comes over the punch ; and t
if that be placed at a proper diſtance, the. ſcale will ſnap
and diſcharge its fire into it. But if a needle be ſtuck on

the end of the punch, its point upwards, the ſcale, inſtead

of drawing nigh to the punch, and fnapping, diſcharges

its fire filently through the point, and rifes higher from the punch. Nay, even if the needle be placed upon the

floor near the punch, its point upwards, the end of the

punch, tho' ſo much higher than the needle , will not at

tract the ſcale and receive its fire, for the needle will get

it and convey it away, before it comes nigh enough for the punch to act. And this is conftantly obfervable in

thefe experiments, that the greater quantity of electricity on the paſteboard tube, the farther it ftrikes or diſcharges its fire, and the point likewife will draw it off at a ftill greater diſtance,
• Now if the fire of electricity and that of lightning be the ſame, as I have endeavoured to fhew at large, in a former paper, this pafteboard tube and theſe ſcales may
4 repreſent electrified clouds. If a tube of only ten feet
long

Obfervations on ELECTRICITY .

65

long will ftrike and diſcharge its fire on the punch at two or three inches diftance, an electrified cloud of per

haps 10,000 acres may ftrike and diſcharge on the earth

at a proportionably greater diftance. The horizontal mo tion of the fcales over the floor, may reprefent the mo tion of the clouds over the earth ; and the erect iron

punch, a hill or high building , and then we fee how

electrified clouds

微 paffing over

hills or high buildings at

too great a height to ſtrike, may be attracted lower till

within their ſtriking diſtance. And lastly, if a needle

fixed on the punch with its paint upright, or even on the floor below the punch, will draw the fire from the fcale filently at a much greater than the ftriking diftance, and fo prevent its deſcending towards the punch ; or if in its courfe it would have come nigh enough to ftrike, yet be

ing first deprived of its fire it cannot, and the punch is thereby fecured from the ftroke. I fay, if theſe things are fo, may not the knowledge of this power of points be of ufe to mankind, in preferving houfes, churches, fhips, &c. from the ftroke of lightning, by directing us to fix on the higheft parts of thofe edifices, upright rods of iron made fharp as a needle, and gilt to prevent ruft ing, and from the foot of thoſe rods a wire down the

outfide of the building into the ground, or down round one of the fhrouds of a fhip, and down her fide till it

reaches the water ? Would not theſe pointed rods proba

bly draw the electrical fire filently out of a cloud before

K

it

66

New Experiments and

it came nigh enough to ſtrike , and thereby fecure us from that moſt ſudden and terrible miſchief?

21. To determine the queftion, whether the clouds

f

that contain lightning are electrified or not, I would pro

2

poſe an experiment to be try'd where it may be done con veniently. On the top of fome high tower or ſteeple, place

a kind of centry- box ( as in FIG. 9. ) big enough to contain a man and an electrical ftand . From the middle of the ſtand

let an iron rod riſe and paſs bending out of the door, and

then upright 20 or 30 feet, pointed very ſharp at the end .. If the electrical ſtand be kept clean and dry, a man ſtand ing on it when fuch clouds are paffing low, might be elec

trified and afford ſparks, the rod drawing fire to him from a cloud. If any danger to the man ſhould be apprehended

(though I think there would be none) let him ſtand on

¦

the floor of his box, and now and then bring near to the

rod the loop of a wire that has one end faftened to the

leads, he holding it by a wax handle ; fo the fparks, if the rod is electrified , will ſtrike from the rod to the wire, and not affect him.

22. Before I leave this fubject of lightning, I may men tion fome other fimilarities between the effects of that, and thoſe of electricity. Lightning has often been known to ſtrike people blind . A pigeon that we ftruck dead to appearance by the electrical shock , recovering life, drooped } about the yard feveral days, eat nothing, though crumbs were thrown to it, but declined and died . We did not

think of its being deprived of fight ; but afterwards a pullet .

Obfervations on ELECTRICITY .

67

pullet ftruck dead in like manner, being recovered by re peatedly blowing into its lungs, when fet down on the floor, ran headlong againſt the wall, and on examination appeared perfectly blind. Hence we concluded that the pigeon alſo had been abfolutely blinded by the fhock . The biggeſt animal we have yet killed, or tried to kill, with the electrical ftroke, was a well-grown pullet. * 23. Reading in the ingenious Dr Miles's account of the thunder ſtorm at Stretham, the effect of the lightning in ftripping off all the paint that had covered a gilt moulding of a pannel of wainſcot, without hurting the reft of the paint, I had a mind to lay a coat of paint over the filletting of gold on the cover of a book, and try the effect of a ſtrong electrical flaſh ſent through that gold from a charged fheet of glaſs. But having no paint at hand, I paſted a narrow ſtrip of paper over it ; and when dry, fent the flash through the gilding, by which the paper was torn off from end to end, with fuch force, that it was broke in feveral places, and in others brought away part of the grain of the Turky-leather in which it was bound ; and convinced me, that had it been painted, the paint would have been ftript off in the ſame manner with that on the wainſcot at Stretham.
24. Lightning melts metals, and I hinted in my paper on that ſubject, that I ſuſpected it to be a cold fufion ; I do not mean a fufion by force of cold, but a fuſion without heat *. We have alfo melted gold, filver, and
* See note in page 49. copper,

68

New Experiments and

copper, in fmall quantities, by the electrical flaſh. The

manner is this : Take leaf gold, leaf filver, or leaf gilt copper, commonly called leaf brafs, or Dutch gold ; cut off from the leaf long narrow ftrips, the breadth of a ftraw. Place one of thefe ftrips between two ftrips of ſmooth glaſs that are about the width of your finger. If one ſtrip of gold, the length of the leaf, be not long e nough for the glaſs, add another to the end of it, ſo that you may have a little part hanging out loofe at each end

of the glaſs. Bind the pieces of glaſs together from end to end with ſtrong filk thread ; then place it fo as to be

part of an electrical circuit, ( the ends of gold hanging out being of ufe to join with the other parts of the circuit) and fend the flaſh through it, from a large electrified

jar or ſheet of glafs. Then if your ftrips of glafs remain whole, you will fee that the gold is mifling in feveral places, and inſtead of it a metallic ftain on both the

glaffes ; the ftains on the upper and under glafs exactly ſimilar in the minuteſt ſtroke, as may be feen by holding them to the light ; the metal appeared to have been not only melted, but even vitrified, or otherwife fo driven into the pores of the glafs, as to be protected by it from the action of the ſtrongeſt Aqua Fortis, or Aqua Regia. I fend you enclofed two little pieces of glafs with theſe metallic ftains upon them, which cannot be removed with out taking part of the glafs with them. Sometimes the ftain fpreads a little wider than the breadth of the leaf,

and looks brighter at the edge, as by inspecting cloſely you

Obfervations on ELECTRICITY.

69

you may obferve in thefe . Sometimes the glass breaks
to pieces ; once the upper glafs broke into a thoufand pieces, looking like coarfe falt. Thefe pieces I fend you were
. ftain'd with Dutch gold. True gold makes a darker ftain , fomewhat reddiſh ; filver, a greenish ftain . We once took
two pieces of thick looking-glafs, as broad as a Gunter's fcale, and fix inches long ; and placing leaf- gold between
them, put them between two ſmoothly plain'd pieces of wood, and fix'd them tight in a book -binder's ſmall prefs ; yet though they were fo clofely confined , the force of the

electrical ſhock ſhivered the glaſs into many pieces. The gold was melted, and ftain'd into the glafs , as ufual . The circumſtances of the breaking of the glafs differ much in making the experiment, and fometimes it does not break.

at all : but this is conſtant, that the ſtains in the upper and under pieces are exact counterparts of each other . And though I have taken up the pieces of glafs between my fingers immediately after this melting, I never could per ceive the leaſt warmth in them.
25. In one of my former papers, I mentioned, that, gilding on a book, though at firft it communicated the
fhock perfectly well, yet failed after a few experiments, which we could not account for. We have fincé found

that one ftrong fhock breaks the continuity of the gold in the filletting, and makes it look rather like duft of gold, abundance of its parts being broken and driven off ; and it will feldom conduct above one ftrong shock. Per haps this may be the reafon : When there is not a perfect
continuity

70

New Experiments and

continuity in the circuit, the fire muft leap over the va cancies : There is a certain diftance which it is able to

leap over according to its ftrength ; if a number of fmall vacancies, though each be very minute, taken to 1 gether exceed that diftance, it cannot leap over them, and fo the fhock is prevented.
26. From the before-mentioned law of electricity, that points as they are more or lefs acute, draw on and throw off the electrical fluid with more or leſs power, and at greater or leſs diſtances, and in larger or ſmaller quantities in the fame time, we may fee how to account for the fituation of the leaf of gold fufpended between two plates, the upper one continually electrified , the un der one in a perfon's hand ſtanding on the floor. When the upper plate is electrified , the leaf is attracted, and raiſed towards it, and would fly to that plate, were it not for its own points. The corner that happens to be up permoft when the leaf is rifing, being a fharp point, from the extream thinnefs of the gold , draws and receives at a diſtance a fufficient quantity of the electric fluid to give itſelf an electric atmoſphere, by which its progreſs to the upper plate is ftopt, and it begins to be repelled from that plate, and would be driven back to the under plate, but that its loweft corner is likewife a point, and throws off or diſcharges the overplus of the leaf's atmoſphere, as fast as the upper corner draws it on. Were theſe two points perfectly equal in acuteness,

the leaf would take place exactly in the middle fpace, for

Obfervations on ELECTRICITY .

71

for its weight is a trifle , compared to the power acting on it : But it is generally neareft the unelectrified plate, becauſe, when the leaf is offered to the electrified plate, at a diſtance, the ſharpeft point is commonly first affected and raiſed towards it ; fo that point, from its greater acuteness, receiving the fluid fafter than its oppoſite can diſcharge it at equal diftances, it retires from the electri fied plate, and draws nearer to the unelectrified plate, till it comes to a distance where the diſcharge can be ex actly equal to the receipt, the latter being leffened , and the former encreaſed ; and there it remains as long as the globe continues to ſupply freſh electrical matter. This will appear plain, when the difference of acuteness in the corners is made very great. Cut a piece of Dutch gold (which is fitteft for theſe experiments on account of its greater ftrength) into the form of FIG. 10 , the up per corner a right angle, the two next obtuſe angles, and the loweſt a very acute one ; and bring this on your plate under the electrified plate, in fuch a manner as that the right-angled part may be firſt raiſed ( which is done by covering the acute part with the hollow of your
hand) and you will fee this leaf take place much nearer to the upper than the under plate ; becauſe without being nearer, it cannot receive fo faft at its right-angled point, as it can difcharge at its acute one. Turn this leaf with the acute part uppermoft, and then it takes place neareſt the unelectrified plate ; becauſe, otherwife, it receives fafter at its acute point than it can diſcharge
at