ELECTRICITY* 
grease it, io wipe off the superfluous grease, tricity, if rubbed with the smooth hair of a 
. 1 . i ' - 1 11 — - — cads skin. 
Amidst this embarrassing variety 
of 
ex- 
and then spread the amalgam. 
One property of the electric fluid it will be _ 
necessary to notice before the conclusion of periineuts, those philosophers who applied to 
1 this branch of science, were eagerly em- 
ployed in inventing theories to account for 
these phenomena, and electricians are stiil 
divided with respect to the cause. 
The theory of Franklin, though not with- 
out its defects, possesses simplicity, and 
accounts for facts in an easy and natural 
manner. It may be resolved into the follow- 
ing axioms: 
1st. The electric matter is one and the 
same in all bodies, and is not of two distinct 
kinds. 
2d. All terrestrial bodies contain a quantity 
of this matter. 
3d. The electric matter violently repels 
itself, but attracts all other matter. 
4th. Glass and other substances, denomi- 
nated electrics, contain a large portion of 
this matter, but are not to be penetrated by 
it. 
5th. Conducting substances are permeable 
tiiis branch of the subject, and that is, that it 
is more forcibly attracted by points than by 
balls or anv blunt or rounded surfaces. 1 his 
may be demonstrated bv a variety of easy 
experiments, and may be seen by presenting 
a metal ball at a given distance to a conduc- 
tor in the act of being charged, when it will 
be found that a metal point presented at a 
much greater distance will draw off the whole 
of the electrical matter from the conductor. 
In the one- case also (the point) the electri- 
city goes off invisibly, and without noise; in 
the other case there are both a flash and a re- 
port. 
Of the theory rf electricity. — In a very early 
stage of the science we have seen, that a dis- 
tinction was observed with respect to the at- 
tractive and repulsive powers of certain elec- 
tric bodies. Thus, if we electrify with the 
same substance, for instance either with ex- 
cited glass or with sealing-wax, t\o ooi k j g v p and t i 0 110 j- conduct it merely over 
balls in an insulated state, that is, suspended | t jj e - lr sur f ace< 
by silk lines about six inches long, tne balls > ^ body may contain a superfluous 
will separate and lepel each other , but it we , quantity of the electrical fluid, when it is said. 
tncity existed ; and the one w as termed the j py exciting an electric, the equilibrium 
vitreous electricity, or that produced I tom 0 f the fluid is broken, and the one body be- 
glass ; and tne other, which was produced C( jines overloaded with electricity, w hile the 
from sealing-wax, resinous substances, and . j s deprived of its natural share, 
sulphur, was termed tne lesinous cleclii-j Thus, according to the Franklineau theory, 
city- j that electricity, which was before called 
Subsequent experiments served to shew, vitreous, is now called positive electricity ; 
that in the common electrical machine, the and that w hich was termed the resinous, is 
rubber exhibited the appearance of the resi- n0 \v denominated negative electricity, 
nous electricity, and the cylinder that of the It is evident, that'll is only in passing from 
vitreous, while the former was connected one body to another, that the effects of the 
with the earth. A divergent cone or brush electrical fluid are apparent. \Vhen all the 
of electrical light was observed to be the ob- adjacent bodies, therefore, are equally charged 
v ions mark of the vitreous electricity; and a ; with electricity, no effects whatever will ap- 
single globular mass of light distinguished the i pear. The equilibrium must, according to 
resinous kind. The hand or body also which | the principles of Dr. Franklin, be destroyed, 
approached the vitreous or glassy substance, i that is, the fluid must be made rarer in some 
when excited, appeared to receive the mat- j one part, before any of the phenomena will 
ter from the electric; but when one of the i be exhibited. In. that case, the. dense fluid 
resinous kind was excited, the electrical mat- j rushing in to supply the deficiency in that 
ter appeared to proceed from the hand or 
other approaching body. 
Notwithstanding, however, the names by 
which these different forms of electricity were 
distinguished, as the vitreous and resinous, it 
was at length discovered, that the different 
phenomena depended rather upon the surface, 
than upon the nature and composition of the 
electric ; for a glass tube, when the polished 
surface was destroyed; by being ground with 
emery, and being rubbed with a smooth 
body, exhibited all the proofs of the resinous 
electricity, as much as sulphur or sealing- 
wax ; yet afterwards, when it was greased and 
rubbed with a rough surface, it resumed its 
former property. It seems, therefore, to be 
a rule, that the smoothest of two bodies, upon 
friction, exhibits the phenomena of the 
vitreous electricity ; for baked wooden cylin- 
ders with a smooth rubber are resinously 
electrified, but with a rubber of coarse flan- 
nel they exhibit the appearances of the 
vitreous kind ; and even polished glass will 
produce the phenomena of the resinous elec- 
part where it is rarer, produces the flash of 
light, the crackling noise, and the other effects 
of electricity. 
The different effects on rough and smooth 
bodies, when excited, have been previously 
remarked. The Franklineau theory is, if a 
rough and smooth body are rubbed together, 
the smooth body will generally be electrified 
plus, and that with a rough uneven surface, 
minus. Thus, in the ordinary operation ot 
the common machine, the cylinder is positive- 
ly electrified, or plus, and the rubber negative, 
or minus. The redundance of the positive 
electricity is sent from the cylinder to the 
prime conductor, and may be communicated 
from it to any conducting body. If, however, 
the prime conductor is made to communicate 
-with the earth, which has a great attraction 
for the electrical matter (and which, being 
one great mass of conducting substances, will 
not permit the accumulation of the fluid in a 
particular part) ; and if, at the same time, the 
rubber is in an insulated state, supported, for 
instance, by glass or any electric ; these effects 
5.9 9 
will be reversed, for the prime conductor 
will then be negatively electrified, and lie 
rubber will be plus or positive. 
Dr. Franklin supposed that the electro 
fluid is collected from the earth, and this 
hypothesis lie supported by the following ex- 
periment. 
Let one person stand on wax (or be in- 
sulated) and rub a glass tube, and let another 
person on wax take the lire from the first, 
they will both of them (provided they do not 
touch each other) appear to be electrified to 
a person standing on the floor ; that is, he 
will perceive a spark on approaching cither of 
them will) his knuckle or linger; but if they 
touch each other during the excitation of the 
tube, neither of them will appear to be elec- 
trified. If they touch one another after ex- 
citing the tube’, and draw the lire us before, 
there will be a stronger .spark between them 
than was between either of them and u.e- 
person on the floor.. After such a strong 
spark, neither of them discovers any electri- 
city. 
He accounts for these appearances by sup- 
posing the electric fluid to be a common 
element, of which each of the three persons 
has his equal share before any operation is 
begun with the tube. 
A, who stands upon wax and rubs the lube, 
collects the electrical lire from himself into 
the glass, and his communication with the 
common stock being cut off by the wax, his 
body is not again immediately supplied. 
Ik who also stands upon wax, passing his 
knuckle along the tube, receives the lire 
which was collected lrom A, and, being in- 
sulated, he retains this additional quantity. 
To the third person C, who stands upon the 
floor, both appear electrified ; for he, having 
only the middle quantity of electrical lire,, 
receives a spark on approaching B, who has 
an over quantity, but gives one to A, v ho- 
llas an under quantity. 
If A and B approach to touch each other,, 
the spark is stronger, because the difference 
between them is greater. After this touch 
there is no spark between either of them and 
C, because the electrical fluid in all is reduced 
to the original equality. If they touch while 
electrifying, the equality is never destroyed, 
the lire is only circulating; hence we say 
that B is electrified positively-, A negatively . 
Such is the famous Franklineau lit pothers, 
which, it must be confessed, is not entirely 
without its difficulties, and, it is much to be 
feared, that we have as yet no complete 
theory of electricity. The fact most difficult 
to be explained on the Franklineau system is, 
that of two bodies negatively electrified re- 
pelling each other ; for if the repulsion in the 
case of positive electricity is caused entirely, 
as there is reason to believe it is, by the 
electric matter, how should a deficiency of 
that matter produce the same effect ? At- 
tempts have been made to explain the fact, 
by having recourse to the electricity of the 
air, which (when not charged with moisture) 
is certainly an electric, or non-conducting 
substance, and in all cases is an imperfect 
electric. T he cork balls, or other light sub- 
stances, which are electrified negatively, are 
therefore supposed to be acted upon by Ihe 
positive electricity of the air, which produces 
an . effect adequate to the being positively 
electrified. This solution, however, is not 
quite satisfactory ; though it is perhaps un- 
