1000000030

474

E L

Thlt tl,e qU:UHily of this m"uer ¿ilfuftd il

alw~)'s

in proponion tOthe

m'S~;lOd~

'oc!

cxt~nlioo

of the

ho.'

,!ies

iot~

\Vhich i; p:tlfcs; aro,1th.n it is uoilormly

clt!–

fufru, no pan

01'

Ihe boJy rw io;ng more Ihao an) other

I'arl.

Th, t, afler beiog th,,: rolUmunimecl to 'ay houy,

il ele<pes with equal flciluy, as foon 's it linus a cOlUmu–

nic~tion

1V;lh the eanh.

That Cm,1I iOlerrllptions in the comiouity of clec–

I,ineu hodics

nOI intmupt the lOotiol1 of the t1ctlli-

matter.

í .

Th~t

the

m~¡ioa

of Ih..

ele·~ri,,1

m,mr is

ama–

zioSly f.l'ifl, th'l il

r~ns

over

fpdCe of

12,000

leet in

an undennable

iu~ant

of lime.

That i: rr,oves with

equ~1

rapidity either bllcklVard

fOiward, upon the ?pplic.nioo of a condllttor.

L,aly, That an ,ndennitcly large quantity of this

maner m2y be accuniul"led by applying the slobe or tube

lOcooduéting bodies of rery \.,rge dimeolions. Of late

other melhods

óf

eoodeoftng a IMge quaotity of eletlricol

maner irolO

~ flO~1I

{'pace have beenioveoled, as will afler–

\Varas appear

h, nwecome

Ireat of ,heLeydeophia!.

The anratlioo aod repulfioo of light boJies, is the

[¡ra

Ihing Ih.t difcows

us the prcfcnce of the e\ctl, i–

cal mmer. This motion is alIVays reeiprocal : rf the

e1etlrified body be lighter Ihan Ihe condu.:tor, and bOlh

are all,beny, Ihe mOlion of Ihe former is quicker Ihan

Ihat of the Imer ¡ if the one be fixed, anu the other at

liberty, the unfi1ed one conlldndy goes tothe one Ihat is

fixed, an.l, at

th~

fame, t,lkes the !hortefi road. Tho

following experiments IV,II íllu(lrate Ih& mOtions.

Pr&n¡ an C\c[lrified t\lbe tO fmall pieces of

r.0ltl·ld plm d on a wcll-polilheJ plate of copper, they

\ViII infiantly Ay101'lal'ds thetube.

2 .

SlIfpend an

elc~lI

ilied lube by tIVO Glk cords; take a

]\im of

gold- I~ar.

and, holding il fi rm

b~IIVixl

your fi n-

1~Cf!,

bri.'g it near l!le tllbe¡ and the tube will be al·

uatled

~nd

100\'e !Oward Ihe Icar.

If an cletl rified perron, (lanJing on a pieee of roGn,

holds in his hand a plm of eopper, upon which pieces

"f guld- Ieaf are pi.leed; and nnolher pe!"on, who is not

deélrilicd, holris his fi nger aboveIhepl.'IC¡ the gnlcl-Ic" f

I.ill innantly rife from

(h~

plate, ftnJ Ay tOIVdrds his nn–

ger.

4. L,nty, If IIVO b, lIs of gilt paper be fufpended fix

,cr.es

afunJer, Ihe ono by a ftlk Ihread time fcet io

I:nc;h, and Ihe other by a fmal! ftlver ",i re of the f.lme

!:nglh; whcn lhe b,1I

f~fp('nJed

by Ihe Glk Ihre.,d is e–

J.:tlrifi~u

by Ihe tllbe, hOlh bl!ls ,dvance wilh equal

,¡uicknefs 10l'l,Irds one anolher, ¡hough oulyone of them

IVaS

eletlrificd.

The moll

f~vomhle circlll11n~nces

for exhibiling the

attraélion of liehl bodi,s are the fullolVing:

J. The, fll nuld be perfctl cond élors.

They

ou~IH

of a fmal! file.

They O,oolcl be rllpported by a non-condutlor, and

raiíccl four

ni'

nve fm lrom Ihe g,ound.

4' No olher non-cnnduélur Ihould be ncarcr the bodies

tl:.o Ihe lOoe IVilh which the experimenls are

m;¡l~ing

ollleJwifc the auraéhoa ..,ii! be

diHul ~d.

T Y.

Repulfton generally fllcceeds attrAélion ;

11.:,(

is, a

picce of

)Id k.f is no fooner aUIi,élc.1hy Ihe lobe Ihan

'1" r'-ptlkd and dri"ln olf from il. Thl5

r~rlllfion

nOt very perceplil,I ' ll'hen the

tub~

n'~htly

c1etl rir:cd:

bu:,

h-n the c1c.:tricuy is bnll<, Ihe g"IJ Icaf neVCT fails

he repdlcd as foon as it ha: looche.! Ihe lobe. Again,

if lhe eletl Tleity be very firong, Ihe gold-Icaf, though

II rongly atlraOed by the tulle, ne"er lUuches it ¡ Ihe re–

pulfl"e powcr brginning 10 operate t\Vo or time inches

before

t~e

b f re...;hes the lube: from that in!l.ult the

leaf is clctlrified ¡

~nd,

Il'hen il begins 10 oe

rCl'dlc,~

has acquifld as denfe andeétriedlatm:,cphere .s

Ih~

tube:

it then A:es olT,

~nd

remains Cllfpendd abo"e the IUbe un–

til it lob the e!etlrie v:rtue it had acqui red, eiócr by

the moill vaponrs in the air, or ,ill il lofes it Cnddenly

by touching fome eonantlor.

Her.ce

il "rpms,

th~t

Al–

tr.ltlion precedes repullion, only becouf. ,t is

necefl~ry

thal Ihe pims of sold-icaf !hot:ld acquire as denfe anal–

mofphere

that of the globe before Ihey can be repelled

by il.

When the tube has repelled a piece of gold leaf, if

anolher lube, nearlyequal'yeletlrined, be fuddenly fub–

flilUted in place of the former tUbe, the Icaf \Vil! conl inoe

to be repelled at an eqnal d,lI.lnee. HUI if the fllbililuled,

tube be much

IcCs

eleélrilied Ihan ¡he original one, Iho

leaf will be auratled by Ihat lube_

When tlVO or more pieces of gold leaf are prefew ,¡

at the COlme t,me to a lVell eleélnfied tube, Ihcy are all

equallyanraeted and rep,lIed ¡ but then they mutually

repe! one another, fothat it is imponible10make any IWO

of them join; and the diaance at \Vhich they repel

on~

anolher is equal tO Ihe difiance tOwbich each

01'

IheOl

\Vere repell:d from Ihe tube.

a circular piece of gold-Ieaf,

Cut

into fmall

fring~s'

to near the cenlre of the Icaf, be prefenled tO an

e1eL~~'-'

fied IUbe, it \ViII fi ra be auratled, and then repcll:d:

¡n.

Ihe time of repulGon, al! the fringes repel cach olher¡

and di"erge more or lers in proporticn

the flrenglh of

eleétricilY in tbe lube.

rf a fmal! metal velfel fi lled wilh water, and furniflleJ

wilh acapillary fiphon, havi ng thelongerle& hanging ?ver

the oUlfttle of the v. lfel be lOuched \Vith an e1etlllfi,d

iron rod· tbe lVater IVhich could nOI run out of tbe fi–

phon bUl' drop by d:op¡ lVill inflantly lIy out a IOne jet,.

and divide itfelf inlo

very

fine Ihreads ¡ and thefe Ihreads

cOOl inue fometimes fufpendeu in Ihe air, repcllcd from each

her to a confiderable diaanee.

Prom thele inllJnces of amatlion and repulfionit ap-'

cars ,

l. Th3t light bodies are attratled by

e1etlnn~d ~ub

fl~nces

unlillhey be eqnally eletlrified byCOOlOlumcatlOn,

anu uOIil they acquire as denfe an atmofphcre as Ihe e–

lel\rified fubaances Ihemfdm.

That, from Ihe monlent Iheyaequire this atmo·

fphere, allra,qion ceafes anJ repulfion bcgins.

l'hll no repulGon takes plm but bClwixt bodres c-

Ictlrificd.

• fi

' . That repulfion conlinucs onlyas long

Iheden

,ty

of ihe I\VO alOlofl'heres are e'lual: that it (c:Ses WhCII–

ever Ihe one or Ihe olh r is dimioinled i lbat a

oewéi~l

tr~

\iOn.