1000000030

in a \'ery inconó,1t r. ble e!egrce: (ueh bodi,s ue calild

Mn.e!d l l'iCl,

c~m¡'¡{IJI'I,

viz.

l .

Waler,

~nd

all aqu':ous

~nd

fpirilllous liquors,

which are incapable of being tbicktned, and fubj,élcJ to

friélion

AII melals. perfdl and imperfetq, anrl lhe greal,ll.

pan of

miner~ls;

as,

Ih~

load·fl one, antimony, zinc,

bifmulh, Ihe agat, the ja(per,

marbl~,

Iree·llone,

¡¡ate,

&c.

3. AII living cmtures, excepting their hair. To

which may be added moll animal.fuil.nees; as I:alher,

parchment, bone, ivory, horn, Ibells,

Oc.

4' Trees and pl.nts of all kinds; thre.d, ropes, li·

nen.clolh , paper,

O,.

Thefe IWO clalfes of bodies have been called by the

name of

,ld/riC!

and

Jlo/l·ddllÍc¡:

uut

the eleélrical

m~tte;

is not contained in the elcélrical bod'es Ihem·

felves, but colleéled by Ihemfromthe eanb : and asnon·

eleélric all ow Ibe. eleélrical matter 10 penelrate and Ro\Y

Ihrough Ihem, or

fpread equally on their furfaces,

Ihe lerms

conduf/or

and

non cond"f/"

are more proper.

Melals .nd waler are the only perfeél coneluélors ; olher

bodies conduéling only as Ihey cont.inamixtureofIhefe,

wilhoul moreor lels of which Iheywill nOIconduél al all.

Although conduélors cannol be eleél rined by heal or

friélion, Ihey may be charged wilh eleélricilY, or ",ade

non·conduélors, by an eafy operalion; bUI Ihen Ihey re·

tain Ihis propeny no longer Ihan Ihey are kepl from

communic~ling

wilh olher conduélors. Abarof ironwill

become an eleélric or noo·conduélor, by being fu fpended

by a filk cord, or

I~id

upona piece of

rofi~

orolha non·

conduc10r, and al Ihe f.1me lime having one end of it in

conl~él

wilh a wel! rubbed

gl.fs

lube, or globe. In Ibe

f~me

manner, waler aud metals of all kinds :nay be clm·

ged with eleélricilY.

is abfolulely

necelf~ry,

in exciting eleélricilY

fri.'lion. th.r the

gl~fs,

or olher body, be perfeélly dry;

Ihe

le~11

moifiure dellroys, or al leal! diminilbes Ihe ef·

feél. A moi!! almofphere, a burning candle,

&c.

are ex–

tremely unfavourable in making elettrical experimenls.

Hollow glafs globes, of aboul a fool diameler, and Ihe

161h pan of

inch Ihick, m now ufed in pllce of

tubes, becaufe il lelfens Ihe labour of friélion, and aecu·

mulales

grea ler

qu~ntity

of cleélrical malter. This

globe is lurnrd rapidly

a large whecJ like Ihofe ufcd

by Ihe euders. When Ihe glube is rubbed, il fuon ae·

quires a confiuerable degree of eltél rical .inue, which is

difcovered hyIlghl bodlel, al Ihe dlfidnce of IWO or Ihree

fecI, flying 10IVard, il. In

~pproachiñg

Ihe olobe IVilhIhe

hand or faee, you \VII! I,kewife (eel Ihe eldlric matter

{urroundingil likea gendebrecze 01' willlJ. Thefe fublile

emanalions conlinue 10 be diffufed round Ihe globe as

long as Ihe friérion i, conlinued : and, whenIhe friélionis

1I0pped, Ihey

~raelually

diminilh, lil! Ihey are no longa

perccpti~le .

1l.e

.pplrcali~n

of non·eunduétors lOd,e

glo"" does nOI dimlnrlh Ihe tlrélrie.11 m.\JIcr : on Ihe

eontrary, Ihe applieatiun o( conduélors almo!! inllamly

annih,hles Ihe I'Ihole quanli,y previoully collt,q·_d by Ihe

friétion. But this

lfi,él

is oor prouuccd, uol fs wlrendIe

condu~lJr

al lhe f, me

:im~

hasa

communic~lioo

wilh II,e

lIoor or ear'lh whcre lhe maehine ¡hn,ts. For, as ah,,"e

obrer.~d,

if Ihe eonduélor has no comnlunicauon wilhIlre

eanh, il eharges with ckéhicilY, an" becomes a nnJl·

eonduélor. HUI non·eondllélors, as a piece of glafs.

ful pltllr, or W1X, though Ihey donOIdíminilhIhevinueof

Ihc globe, yel Ihey do nOI acquire,

I,k~

iron,

6c.

Ihe

propcrty of a'lraélion or repulfion. Hence il appears,

th;\I Ihe eleélrical maller palfes freely along condullors.

and dilT.pates in Ihe

e~rth;

bUI, on Ihe conlrary. lhal

non conJuétors do nOI receive any matter (romIhe gl(lbe.

aod are incapable of Iranfmiuiog il. The following

experimenls \\'ill make Ihis more plain.

l .

If a pieee of iron be placedon a glafs fiandard, ,od

unconncél~d

wilh any olher body, as foon as Ihe e",qri·

cal maller is communic'lcd 10 il, il attraéls and repcls

pieces of gole! bf or olher lighl bodies. and preferl'esIhis

vinue even for fome minules afler ilscommunicalionwilh

Ihe glube is eUI oIF. !luI, if a piece of glafs, rofi n,

any olher non·conuuélor, be placed in Ihe fame circum·

llanees, Ihey do nOIdifcover any (ueh elfcél.

If a perfon louches Ihe piece of iron

~bove

meno

tionedwilhIlIs

h~nd,

nOfriélion is capableof makingilal–

mél or repel, or exhibil any marks o( eleélrimy. The

fam~

Ihing happens, if a ehain of any melal louch Ihe

iron,

~nd

al Ihe fame lime has a eommunicalion wilh

Ihe glound. In both Ihefe cafes, Ihe eleélrical maner

palfes along Ihe iron, and dillipares in Ihe earrh.

j .

In place of lOuchingIhe píeee of iron wilhIbe fin·

ger, if a piece of amber, wax, or any olher non·con·

dllélor beapplied 10 il, Ihe eomnlunicalionwilh Ihe eanh

being inlen upled byIhe non·conduélor, Ihe iron, in Ihal

c&, retains Ihe

eleélric~1

matter as before.

Fronl Ihefe experimenrs we learn, Ihal mel. ls and o·

Iher conduélors receive the eleét rical maller, anel Iraor–

mil il 10 olher conduélors lil! il ditrufes and is loll in Ihe

eanh; bm Ihal, if wax, glafs. or any Olher non·con·

<luélor, be' applied

Ihe eonduélor, Ihe mOlioosof Ihe

maller is inllantly !!OpI, and accumulates and eharges

Ihe conduélol, al Ihe f,me lime Ihal the non·cun·

duélol ilfelf is nOIall alfcéled.

is for Ihis reafon Ihal

eonduélors, as filk·cords, hair·ropes,

&c.

are alw,ys

employed 10 fllfpend or fuppon (uch bornes as \Ve wanl

lOcharge wilh eleélricilY.

The (óllolVing experimems will Ihrowfunher llghl on

Ihis fubjeél.

man flands upon

piece of rofin abo\IJ óve

In~h.

es in

dí~meler,

and feven or eighl inches Ihick, louchlng

foftly Ihe glol1e, IVhile Ihe operalor is rubbing

i~,

IJlS

whole body. in a few (cconds, wil! be charged

~vJlh

leél rical mmer ; and Ihe follolVíng ph:enomena WII! lake

place.

l .

His loofe hano, and inoeed every parl of hisbocly,

will Oluluatly anraél and repellight bodies at the dinan"

of Ihree or four feer.

..'I

AII conduélors II'hieh he lakes In

IIIS

hano, wII

beeflOlc tlc,qrifi,,1 in Ihe f.I01C manncr ",ilh himfdf, pro·

"iJet! Ihey louch nOlhing elfc, or he: fupponed uponnon'

cunduétors: and Ilris cummuniralion lOotber condull ors ,

111