ELECTRICITY. 
5U.5 
culars, viz. the king of Bohemia, count pala- 
tine of the Rhine, duke of Saxony, and mar- 
quis of Brandenburg. In 1648, this order 
was changed, the duke ot Bavaria being put 
in the place of the count palatine, who, hav- 
ing accepted the crown ot Bohemia, was out- 
lawed by the emperor ; but being at length 
restored, an eighth electorate was erected tor 
the duke of Bavaria. In 1692, a ninth elec- 
torate was created by the emperor Leopold, 
m favour ot the duke ot Ilanover, ot the 
house of Brunswic Lunenburg. 
There are now, or at least were a short 
time since, ten electors, viz. the king or elec- 
tor of Bohemia ; the elector of Bavaria, now 
a king also ; the elector of Saxony ; the elec- 
tor of Brandenburg (king of Prussia); the 
elector of Ilanover, at this moment, by an 
usurped authority, king of Prussia also; the 
elector arch-chancellor of the empire, whose 
residence is at Ratisbon ; the elector of Salls- 
burgh ; tin* elector of Baden ; the elector of 
\Vurtemburgh ; and the elector of Hesse. 
ELECTRICITY, is a term used to denote 
the operations of a very subtile fluid, - in most 
cases invisible, but which sometimes becomes 
the object of our senses, proving itself to be 
one of the principal agents employed in pro- 
ducing the phenomena of nature. 
History of discoveries relative to electricity. 
The attractive power which amber and 
other electric bodies acquire by friction, was 
long known to philosophers ; and it is almost 
unnecessary to remark, that this branch of 
science derives its name from t\e»lpo» (elec- 
tron), the Greek word for amber. The other 
electric properties were slowly discovered. 
Mr. Boyle was the first who had a glimpse 
oi the electric light; as he remarked, after 
rubbing some diamonds in order to give 
them the power of, attraction, that they afford- 
ed light in the dark. 
Otto Guericke, burgomaster of Magde- 
burg, made an electric globe of sulphur; and 
by whirling it about in a wooden frame, and 
rubbing it at the same time with his hand, he 
performed various electrical experiment 
He added to the 
stock of knowledge the dis- 
ling noise, was accompanied by an acute 
sense of feeling when applied to his hand. 
He says that all the powers of electricity were 
improved by warmth, and diminished by 
moisture. 
Hitherto the distinction between those 
bodies which are capable of being excited to 
electricity and those which are only capable 
of receiving it from the others, appears 
scarcely to have been suspected. About the 
year 1729, this great discovery was made by 
Mr. Grey, a pensioner of the Charter-house. 
After some fruitless attempts to make metals 
attractive by heating, rubbing, and hammer- 
ing, he conceived a suspicion, that as a glass 
tube, when rubbed in the dark, communi- 
cated its light to various bodies, it might 
possibly at the same time communicate its 
power of attraction to them. In order to 
put this to the trial, lie provided himself with 
a tube three feet five inches long, and near 
an inch and one-fifth in diameter : the ends 
of the tube were stopped by cork ; and he 
found that when the tube was excited, a 
down feather was attracted as powerfully by 
the cork as by the tube itself. - To convince 
himself more completely, he procured a small 
ivory ball, which he lived at first to a stick ot 
fir four inches long, which was thrust into the 
cork, and found that it attracted and repelled 
the feather even with more vigour than the 
cork itself. He afterwards fixed the ball 
upon long sticks, and upon pieces ot brass 
and iron wire, with the same success ; and 
lastly, attached it to a long piece of pack- 
thread, and hung it from a high balcony, in 
which state he found that by rubbing the 
tube the ball was constantly enabled to at- 
tract light bodies in the court below. 
llis next attempt was to ascertain whether 
this power could be conveyed horizontally 
as well as perpendicularly : with this view he 
fixed a cord to a nail which was in oneot the 
beams of the ceiling, and making a loop at 
that end which hung down, iie inserted his 
packthread, with the ball which was at the 
end of if, through the loop ot the cord, and 
retired with the tube to the other end ot the 
room ; but in this state lie found that his 
ball had totally lost the power of attraction, 
•covery that a body once attracted by an ex- j jy p OU mentioning his experiments to a friend, 
cited electric was repelled by it, and not at- j q was suggested, that the cord which he had 
tracted again till it had touched some oilier v ,sed to support his packthread might be so 
he was able to keep a feather coarse ys y, intercept the electric power, and 
body. Thus 
suspended in the air over his globe of sul 
phur ; but lie observed, that if he drove it 
near a linen thread, or the flame of a candle, 
it instantly recovered its .propensity for ap- 
proaching the globe again. 1 he hissing noise, 
and the gleaming light, which his globe afford- 
ed, both attracted his notice. 
These circumstances were, however, after- 
wards accurately remarked by Hr. Wall: 
who, by rubbing* amber upon a woollen sub- 
stance in the dark, found also that light was 
produced in considerable quantities, accom- 
panied with a crackling noise ; and what is 
still more extraordinary, he adds, “ this light 
and crackling seems in'sonie degree to repre- 
sent thunder and lightning.” 
Mr. Hawksbee first observed the great 
electric power of glass. He constructed a 
wooden machine, which enabled him conve- 
niently to put a glass globe in motion. He 
confirmed all the experiments ot Dr. \\ all. 
He observed, that the light emitted by the 
friction of electric bodies, besides the crack- 
ept the electric pow 
they accordingly attempted to remedy this 
evil by employing a silk string, which was 
much stronger in proportion to its size than 
a hempen cord. With this apparatus the 
experiment succeeded far beyond their ex- 
pectations. Encouraged by this success, and 
attributing it wholly to the fineness' of the 
silk, they proceeded to support the pack- 
thread to which the ball was attached by 
very line brass and iron wire ; but, to their 
utter astonishment, found the effect exaclly 
the same as when they used the hempen 
cord ; the electrical virtue utterly passed 
away ; while, on the other hand, when the 
packthread was supported by a silken cord, 
they were able to convey the electric virtue 
76 j feet. 
It was evident, therefore, that these effects 
depended upon some peculiar quality in (lie 
silk, which prevented it from conducting 
away the electrical power, as the hempen 
cord and the wire had done. This, probably, 
immediately led to the discovery of other 
4 E 2 
non-conducting bodies;' and hair, rosin, glass, 
Ac. were presently made use of to insulate 
the bodies which were electrified, i he next 
obvious improvement was to electrify sepa- 
rate bodies, by placing them upon non-con- 
ductors; and in this manner Mr. Grey and 
his friend Mr. Wheeler electrified a large 
map, a table-cloth, &c. See. In the latter 
part of (he same, summer, Mr. Grey found 
that he could electrify a rod as well as a pack- 
thread, without inserting any part into bis- 
excited tube, and that it only required to be 
placed nearly in contact with the apparatus. 
Mr. Grey proceeded to try the effects ol 
electricity upon animal bodies. lie suspend- 
ed a hoy on hair lines in a horizontal posi- 
tion ; and bringing the excited tube near his 
feet, he found that leaf-brass was attracted 
very vigorously by the head of the boy. He 
found also, that lie could communicate elec- 
tricity to fluid bodies, by insulating them 
upon a cake of ro.in; and observed, that 
when an excited tube was held over a cup ot 
water, the water was presently attracted, in a 
conical form, towards the tube; that the 
electric matter passed from the tube to the 
water with a slight flash and a crackling 
noise ; and that the fluid subsided with a 
tremulous and waving motion. 
After this period-the spirit of philosophy in 
this branch was no longer confined to Eng- 
land. M. Du Fay, intendant of the Frejacli 
king’s gardens, added to the stock of disco- 
veries. He found that all bodies, except 
metallic, soft, and fluid ones, might be made 
electric by first heating them, and then rub- 
bing them on any sort of cloth. He also- 
excepts 'those substances which grow soft by 
heat, as gums, or which dissolve in water, as 
glue. In pursuing Mr. Grey’s experiments 
with a packthread, See. lie perceived that they 
succeeded better by wetting the line. r I o 
prove the effects of this wonderful agent on 
the animal body, he suspended himself by 
silk cords, as Mr. Grey had suspended the 
boy, and in this situation he observed, that 
as soon as he was electrified, if another per- 
son approached hint, and brought Ins hand 
or a metal rod within an inch of his body, 
there immediately issued from it one or more 
prickling shoots, attended with a snapping 
noise ; and he adds, that this experiment oc- 
casioned a similar Sensation in the person who 
placed his hand near him. In the dark he 
observed that these snappings were occasion- 
ed by so many sparks of fire. 
Mr. Grev, on resuming his experiments, 
immediately concluded from that of M. Du 
Fay, in which a piece of metal drew sparks 
from the person electrified, and suspended 
on silk lines, that if the person and the metal 
changed places, the effect would be the same. 
He accordingly suspended a piece of metal 
by silk threads near his excited tube, and 
found that he drew sparks from it at plea- 
sure. This was the origin of metallic con- 
ductors. Mr. Grey suspected that the elec- 
tric lire might be of the same nature with 
thunder and lightning. 
To the philosophers of Germany w.c are 
indebted for most of the improvements in the 
electrical apparatus. They revived the use 
of the globe, which had been invented by 
Mr. Hawksbee, which was afterwards super- 
seded by a cylinder, and to which they im- 
parted a circular motion by means of wheels, 
and used a woollen rubber instead of the 
