423 
ELECTRICITY. 
as to its kind, and the degree of multiplication is little 
more than an amufement. The fpark may even ferve to 
give an indication of the original intenfity, by means of 
the number of turns neceffiary for producing it. If the 
fine wires, which form the alternate connections in fo in¬ 
genious a manner, were tipped with little balls to pre¬ 
vent the diflipation, it would be a great improvement. 
An alternate motion, like that of a pump-handle, might 
alfo be adopted with advantage. This would allow the 
plates to approach each other face to face, and admit a 
greater multiplication, if thought neceffiary. 
There remains nothing more to notice of the apparatus, 
except that minutiae which will occur to every perfon 
difpofed to engage in eledfrical experiments. Among 
fitch we may notice fome glafs tubes about three feet 
long, and an inch and a half in diameter, one of which 
fhould be clofed at one end with a brafs cap and (fop- 
cock, to rarefy or condenfe the inclofed air; fome (licks of 
fealing-wax, or tubes of rough glafs, or glafs tubes covered 
with fealing-wax, or cylinders of baked woodforproducing 
the negative eledfricity; with proper rubbers, as black 
oiled filk, with amalgam upon it for the former, and foft 
new flannel, or hare-fkins or cat-fkins tanned with the 
hair on, for the latter; coated plates of glafs for fimilar 
ufes as the Leyden jar; metal rods as difchargers ; fmall 
glafs fpheres or globes ; infulating (fools, fupported by 
pillars of glafs covered with fealing-wax, or of baked 
wood, to keep the eledtric fluid from palling to the earth ; 
a pot of amalgam, See. The bed kind of amalgam is that 
of Dr. Higgins compofed of zinc and quickfilver. If a 
little of the latter be added to melted zinc, it renders it 
eafily pulverable, and more quickfilver mud be added in 
due proportion for a very foft amalgam. 
PRINCIPLES or LAWS of ELECTRICITY. 
Modern eledtricians, with almoft one confent, appear 
tefbelieve in the exiftence of a fluid fui generis, and to 
have adopted the Franklinian hypothefis of the action of 
that fluid, by attraHion and repuifion. There are fome, 
however, whofe diffident and fcrupulous minds, not being 
as yet fatisfied with the chemical theory of phlogiffon, 
fire, heat, or caloric, (fill rejedf the dodtrine of an elec¬ 
tric fluid, and attempt to deduce the laws of the eledtri- 
cal phenomena, not from the prefence of any peculiar 
fubjiance, but from peculiar nodes-, on the principle that 
found, and fome concomitant motions, and other mecha¬ 
nical appearances, are the refults of the elaffic undula¬ 
tions of air; juft as lord Bacon and others have explained 
the effedts of fire by elaftic undulations of the integrant 
particles of tangible matter. There feems nothing, 
iiowever, of this kind, that can give any explanation of 
the motions, preffiures, and other mechanical appearances, 
of electricity. This requires, that every dodtrine which 
claims the name of an explanation, (hall be perfectly 
confident with the acknowledged laws of mechanifm; 
and that the explanation (hall confift in pointing out thofe 
mechanical laws, of which the fadts in eledtricify are par¬ 
ticular inftances. It may not be difficult to pre’fent an 
intricate or complex phenomenon to our view, in fuch a 
form, that it (hall have fome refemblance to fome other 
complex phyfical fadt, more familiar, perhaps, though 
not better underftood. But this will not (land againft the 
eftabliftied law of eledfricity by attradtion and repuifion ; 
a circumftance wliich admits of the moll accurate exa¬ 
mination and comparifon with any explanation that is at¬ 
tempted. 
Many philofophers, and among them fome refpedtable 
mathematicians, have fupported the dodtrine of Du Faye, 
Symmer, Cigna, &c. who employ two. fluids as agents 
in all eledfrical operations. It muff be confeffied that 
there are fome appearances where the explanation by 
means of two fluids feems, at firft fight, more palpable 
and eafier conceived. But whenever we attempt to ob¬ 
tain mcafures, and to fay what will be the precife kind and 
degree of the eledfricity, we find outfelves obliged to 
affign to the particles of thofe fluids actuating mecha¬ 
nical forces precifely equivalent to thofe of the fingle 
fluid only. ♦ 
Mr. PrcfefTor Ruffe!, of the univerfity of Edinburgh, 
in his theory, confiders tire eledfrical phenomena as the 
refults of the adtion of a fubftance which may be called 
an e/cdiricalfuid, connected with bodies by attractive and 
repulfive forces adting at a diftance, and diminifhing as 
the diftance increafes. Mr. Ruffiel (peaks of the eledtric 
fluid as a compound of feveral others ; and, particularly, 
as containing elementary fire, and deriving from it a great 
elafticity, or mutual repuifion of its particles. This, 
however, is different from tire elafticity or mutual repui¬ 
fion of the particles of air, becaufe it adts at a diftance ; 
whereas the particles of air adt only on the adjoining par¬ 
ticles. By this conftitution, bodies containing more elec¬ 
tric fluid than the fpaces around them repel each other ; 
and the particles of this eledtric fluid attract the particles 
of other bodies with a force which dimini fhes by diftance. 
The charadteriftic ingredient of this fluid is electricity 
properly fo called. This is united with the elaftic fluid by 
chemical affinity, which Mr. Ruffel calls eledtive attraction, 
a term lately introduced into chemiftry. This lie fup- 
pofes to extend to all diftances, but not precifely by the 
fame law' as the mutual repuifion of the particles of the 
other fluid, and in general, it repreffies the repulfions of 
that fluid while in this ftate of compofition. This elec¬ 
tricity, moreover, attradls the particles of other bodies, 
but with certain eledtions. Non-eledtric or condudting 
bodies are attradfed by it at all diftances ; but eledtrics 
adf on it only at very fmall and infenfible diftances. At 
fuch diftances its particles alfo attract each other. The 
phenomena of light and heat are confidered as marks of 
partial decompolition, and as* proofs of the prefence of 
elementary fire in the compound: the fmell peculiar to 
eledtricity, and the effedt on the organ of tafte, are proofs 
of decompofition and of the complex nature of the fluid. 
Bodies or condudtors containing eledtric fluid, repel each 
other at confiderable diftances, but, if forced very near, 
attradt each other.. Eledtrics can contain it only in con- 
fequence of the eledtricity in the compound. Part of this 
eledfricity muft be attached to the furface in a non-elaffic 
ftate; becaufe when it is brought fo near as to be attradf- 
ed, its particles are within the fpheres of each other’s 
adtion, and this redoubled attraction overcomes the re¬ 
puifion occafioned by its union with the other ingredient; 
and the eledtric fluid is partly decompofed, and" the elec¬ 
tricity^ properly fo called, adheres to the furface of the 
eledtric, as the water of damp air adheres to a cold pane of 
glafs in our windows. Alfo, by this conftitution, eledtric 
fluid may appear in two (fates; elaftic, like air, when en¬ 
tire ; and unelaftic, like water, wdien partly decompofed 
by the attradtion of eledtrics. But the attentive reader 
will eafily (ee, that all this intricate combination of diffe¬ 
rent kinds of attradtion and repuifion is nothing but mere 
accommodations of hypothetical forces to the phenomena. 
This, and the more recent though fimilar theory of M. 
de Luc, have, for thefe reafons, fallen to the ground. 
1 lie laws of electrical phenomena, founded on the 
principles of attradtion and repuifion, are accommodated 
to the fadt, that bodies in their natural ftate, having rheir 
natural quantity of eledtric fluid, are altogether inadtive 
on each other, by making this natural quantity fuch, 
that its mutual repuifion exadtly balances its attradtion 
for the common matter. Hence it follows, that the elec¬ 
tric phenomena muft be deduced from a redundancy or de- 
jicicncy of electric fluid. This is the Franklinian dodtrine. 
The redundant ftate of a body, is called by Dr. Franklin 
positive or PLUS electricity, and the deficient ftate 
is called negative or minus electricity. When a 
body contains more than its natural quantity, or lefs, it 
will be redundant in the one cafe, and deficient in the 
other. Thefe different conditions exhibit different ap¬ 
pearances, which conftitute the adtion of the eledtric 
fluid. And hence, in the firft cafe, wherever the eledtric 
fluid 
« 
t 
