ELECTRICITY. 
596 
hand. Ry the great force also of their ma- 
chines they were able to set on fire some of 
the most inflammable substances, such as 
highly rectified spirits, by the electric spark. 
Rut the most surprising discovery was that 
which immediately followed these' attempts, 
in the years 1745-6, viz. the method cf accu- 
mulating the electric power bv the Leyden 
phial. M. A on Kleist, dean of the cathedral 
of Camnin, was the first who found that a 
nail or brass wire, confined in an apothecary’s 
phial, and exposed to the electrifying glass, 
or to the prime conductor, had a power of 
collecting the electric virtue so as to produce 
the most remarkable effects. He soon found 
that a small quantity of fluid added to it in- 
creased the power; and successive electri- 
cians found that fluid matter, or any con- 
ducting body confined in a glass vessel, had 
this power of accumulating and condensing 
the electric virtue. The shock which an 
electrician is enabled to give by means of 
the Leyden phial is well known; and this 
was soon followed by another improvement, 
that of forming what is called the electric 
battery, by increasing the number of phials, 
or jars, by which means the force is propor- 
tionally increased. By these means the elec- 
tric shock was tried upon the brute creation, 
and proved fatal to many of the smaller ani- 
mals, which appeared as if killed by light- 
ning. By these means also the electric mat- 
ter was conveyed to great distances : by the 
French philosophers, for near three miles ; 
and by Ur. Watson, and some other mem- 
bers ol the Royal Society, it was conveyed 
by a wire over the river Thames, and back 
again through the river, and spirits, were 
kindled by the electric fire which had passed 
through the river. In another experiment 
by the same gentleman, it was found that the 
electric matter made a circuit of about four 
miles instantaneously. 
The next discovery respects the nature, or 
rather the origin, of the electric matter. Dr. 
Watson was first induced to suspect that the 
glass tubes and globes did not contain the 
electric power in themselves, by observing, 
that upon rubbing the glass tube while lie 
was standing on cakes of wax, in order to 
prevent, as he expected, any of the electric 
matter from discharging itself through his 
body on the floor, the power was so much 
lessened, tlwit no snapping could be observed 
upon another person’s touching any part of 
his body; but that if a person not electrified 
held Ills hand near the tube while it was rub- 
bed, the snapping was very sensible. The 
event was the same when the globe was 
whirled in similar circumstances ; for if the 
man who turned the wheel, and who, toge- 
ther with the machine, was suspended upon 
silk, touched the floor with one foot, the fire 
appeared upon the conductor; but if he kept 
himself free from any communication with 
the floor, no fire was produced. From these 
and other decisive experiments, Dr. Watson 
concludes, that these 'globes and tubes are 
no more than the first movers or determiners 
of the electric power. 
M. Du Fay had made a distinction of two 
different species of electricity, one of which 
he called the vitreous, and the other the re- 
sinous electricity ; and soon after the disco- 
very of the Leyden phial, it was found, that 
by coating the outside of the phial with a 
conducting substance, which communicated 
by a wire with the person who discharged 
the phial, the shock was immensely increas- 
ed ; and indeed it appeared that the phial 
could not be charged unless some conduct- 
ing substance was in contact with the outside. 
Dr. Franklin, however, was the first who ex- 
plained these phenomena. lie shewed that 
the surplus of electricity, which was received 
by one ot the coated surfaces of the phial, 
was actually taken from the other ; and that 
one was possessed of less than its natural 
share of the electric matter, while the other 
had a superabundance. These two different 
states ot bodies, with respect to their portion 
of electricity, lie distinguished be the terms 
plus or positive, and minus or negative ; and 
it was inferred from the appearances that 
bodies which exhibited what M. Du Fay 
called the resinous electricity, were in tiie ... 
state of minus, that is, in the slate of attract- of 
ing the electric matter from other bodies, 
while those which were possessed of the vi- 
treous electricity were bodies electrified plus, 
or in a state capable of imparting electricity 
to other bodies. By this discovery Dr. 
Franklin was enabled to increase the electric 
pow er almost at pleasure, namely, by con- 
necting the inside of one phial with the in- 
side ot another, in such a manner that the 
fluid which was driven out of the first would 
he received by the second, and what was 
driven out of the second would be received 
by the third. See. and this constitutes what 
we now call an electrical battery. 
But the most astonishing discovery which 
Franklin, or perhaps any other person, ever 
made in this branch of science, w as the de- 
monstration of what had been slightly sus- 
pected by others, the perfect similarity, or 
rather indentity, of lightning and electricity. 
The doctor was led to this discovery In- com- 
paring the effects of lightning with those of 
electricity, and by reflectin 
- that if two gun- 1B . 
barrels electrified will strike at two inches, ! nf -ul tuL 
and make a loud report, what must be the " 1 ' 1 
effect of ten thousand acres of electrified j 
cloud. Not satisfied, however, with specu- ‘ 
lation, he constructed a kite with a pointed 
wire fixed upon it, which, during a thunder- ; 
storm, he contrived to send up into an elec- : 
trical cloud. The wire in the kite attracted 
the lightning from the cloud, and it descend- 
ed along the hempen string, and was received 
by a key tied to the extremity of it, that 1 
part of the string '"which lie held in his hand 
being of silk, that the electric virtue might , 
stop when it came to the key. At this key j 
he charged phials, and from the fire thus ob- ! . 
tained he kindled spirits, and performed all : depends not on any property inherent in the 
the common electrical experiments. an . e atmosphere, for three obvious rea- 
proofs of negative, electricity as much as sul- 
phur or sealing-wax, and drew sparks from the 
knuckle when applied to it, instead of giving 
lire from its own body; when the tube was 
greased, and a rubber with a rough surface 
was applied to it, its positive power was re- 
stored, and the contrary when the rubber 
became smooth by friction. 
General principles of electricity . — From 
the brief account which has been given of 
discoveries relative to this branch of science, 
the reader will be prepared to admit that 
electricity is the action of a bodv put in a 
state to attract or repel light bodies placed 
at a certain distance ; to give a slight sensa- 
tion to the skin, resembling in some measure 
that which we experience in meeting with a 
cobweb in the air; to spread an odour like 
the phosphorus of Kunkell; to dart pencils 
ght from the surface, attended with a 
snapping noise, on the approach of certain 
substances ; lastly, that the body put in this 
state is capable of communicating to other 
bod es the power of producing the same ef- 
fects during a certain time. 
| The electric power is indubitably the ef- 
i feet ot some matter in an active state, either 
; within or round the electrified body ; since, 
if we place either our hands or Lee before an 
: excited tube of glass, or before an insulated 
, conductor which is electrified, we shall per- 
ceive emanations sensible to the touch ; and 
if we approach nearer, we shall feel it distinct- 
i ly, and hear a weak noise : in the dark we 
: perceive sparks of vivid light, especiallv from 
; angular points; we see emitted pencils of 
rays, or small flashes of divergent flame; it 
is certain, therefore, that some subtile matter 
put in motion is alone capable of making 
these impressions upon our senses ; and we 
may conclude that every electrified bodv is 
encompassed by some matter in motion, 
which is, without doubt, the immediate cause 
phenomena, and which 
we term the electric matter or fluid. 
Thus far, and no farther, are we warranted 
in affirming, on the only evidence to be admit- 
ted in philosophy, that of experiment, fact, 
and observation. 'There is, however, in man, 
a curiosity that prompts us to look beyond 
effects, and a disposition that leads us to the- 
orize, even on the most difficult subjects. 
Let us, however, do it with diffidence and 
caution. What, then, is this electric matter? 
or w’hence does it derive its origin? It appa- 
rently proceeds not from the electrified body, 
for that suffers no sensible diminution. It 
experiment 
Dr. Franklin, after this discovery, con- 
structed an insulated rod to draw the light- 
ning from the atmosphere into his house, in 
order to enable him to make experiments 
upon it: he also connected with it two bells, 
which gave him notice by their ringing when 
his rod was electrified. This was the origin 
of the metallic conductors now in general 
use. 
It was afterwards discovered by Mr. Can- 
ton, that the positive and negative electri- 
city, which were supposed to depend upon i 
the nature of the excited body, and therefore 
had obtained the names of resinous and vi 
sons: first, because electrical phenomena 
may be produced in a space from which the 
air has been most carefully exhausted. Se- 
condly, because the electrical matter has 
qualities which are not inherent in air: it 
penetrates certain bodies impervious to air, 
such as metals; it has a sensible odour; it 
appears itself inflamed ; it is capable of in- 
flaming other bodies, and of melting metals ; 
effects which air cannot produce. Thirdly, 
its motion is considerably more rapid than 
that of sound, which is a motion of the air 
the most rapid that we are acquainted with. 
It is, however, generally agreed, that the 
treous, depended chiefly upon the nature of I electric matter has a strong analogy with the 
the surface; for that a glass tube, when the j matter of heat and light, it appears, indeed, 
polished surface was destroyed, exhibited 1 that Nature, who is so very economical in 
