604 
and it has been called the electrical cohe- 
sion. I his was pleasantly illustrated by 
some experiments on silk stockings, com- 
municated to the Royal Society by Mr. Ro- 
bert bymner a few years ago. Two silk 
s ot kings, the one black and the other white, 
l( )cen for some time upon one leg, and 
w l '} *’ j ' 501 }. rubbed with the hand, and both 
(Juliecl off together; it appears that in this 
case the two stockings will adhere together 
in such a manner as to require a considerable 
torce to separate them. M. Brisson, who 
repeated the experiment, observes, that af- 
V t- separated the white from the 
b f k Rocking another phenomenon occur- 
red for while he held them one in each 
Kind, suspended in the air, they swelled and 
puffed up as wide as if the leg had remained 
■ u them ! \\ hen they were brought within 
1 n , °[ twelve inches of each other, they 
. 1 iimyd upon one another, and adhered for- 
‘ together; but this adhesion was not 
so gj eat as that which took place while the 
stocking's were one within the other. Mr. 
• \ inner supposed, that the success of this 
< xpenment depended upon the contrast be- 
tween the black and white colour ; but M. 
Brisson proves this hypothesis to be without 
.foundation, having made the experiment by 
.substituting for the black stocking another of 
a different colour, and even a white one ; but 
ie confesses, that when the experiment was 
made with two white silk stockings the ef- 
xects were weak in comparison. The same 
effects have been produced, when the stock- 
U’o? "'.ere one of black silk, and the other 
of light-coloured Angola wool. 
Electrical attraction .appears, however, 
Jiot to be so strong, in vacuo as in the open 
air. from several experiments of Beccaria’s 
"e learn, that if the air is thoroughly ex- 
hausted out of a glass receiver, the attrac- 
tion and repulsion of electrified light bodies 
within the receiver become languid, and 
soon cease altogether. 
1 hat the stream of electricity is ca- 
pable of producing motion in almost a simi- 
lar manner to a stream of common air, will 
be manifest from several pleasing experi- 
ments. If a brass cross or fly, such as that 
in tig. 14. is placed on the conductor, when 
the machine is turned it will go rapidly 
round. If it is taken off, and held under 
the conductor, it will move in the same man- 
ner. If the cross, or fly, as it is called, is in- 
sulated, it will not move, because no elec- 
tricity can be drawn through it either way. 
If a pin or any other conductor approaches 
it, it will however move as usual. 
By means of the stream of electricity is- 
suing from a point, many other amusing ex- 
periments have been contrived : such is the 
electrical orrery, shewing the motion of the 
sun, earth, and moon. 
I he sun and earth go round the common 
centre of gravity between them in a solar 
year ; and the earth and moon go round the 
common centre of gravity between them in 
a lunar month. These motions are repre- 
sented by an electric al experiment as fol- 
lows : 
The ball S (fig. 23) represents the sun, E 
the earth, and M the moon, connected by 
wires a c and b d: b is the centre of gravity 
between the earth and moon. These three' 
balls and their connecting wires are hung 
and supported on the sharp point of a wire 
ELECTRICITY. 
A, which is stuck upright in the prime con- 
ductor B of the electrical machine ; the 
earth and moon hanging upon the sharp 
point of the wire c a e, in which wire is a 
pointed short pin, sticking out horizontally 
at c ; and there is just such another pin at d, 
sticking out in the same manner, in the wire 
that connects the earth and the moon. 
\\ lien the cylinder of the electrical 
machine is turned, these balls and wires 
are electrified ; and the electrical fire, 
Hying off horizontally from the points c and 
d, causes S and E to move round their com- 
mon centre of gravity a, and E and M to 
move round their common centre of gravity 
b. And as E and M are light when com- 
pared with S and E, there is much less fric- 
tion on the point b, than S and E make 
about the point a. The weights of the balls 
may be adjusted so, that E and M may go 
twelve times round b, in the time that S' and 
E go once round a. This affords an amusing 
experiment in electricity ; but it is so far 
from proving that the motions of the planets 
in the heavens are owing to a like cause, 
that it plainly proves they are not ; for the 
real sun and planets are not connected by 
wires or bars of metal, and consequently 
there can be no such metallic points as c 
and d between them. And without such 
points, the electric fluid would never cause 
them to move ; lor, take away these points 
in the above-mentioned experiment, and the 
balls will continue at rest, let them be ever 
so strongly electrified. 
Fig. 24 represents a water-mill for grind- 
ing corn, turned by a stream of electricity. 
A is the water-wheel, B the cog-wheel (m 
its axis, C the trundle turned by that wheel, 
and D the running mill-stone on the top of 
the axis of the trundle. It may easily be 
contrived and turned also by electricity, if 
instead of the round plate D for the mill- 
stone, there is a horizontal wheel on the 
trundle C, with spur-cogs, which will turn 
two trundles placed on its opposite sides ; 
and on the top of each of these trundles’ 
axis, may be a round plate representing a 
mill-stone ; so that this model lias all the 
working parts of a double water-mill, turning 
two mill-stones. 
Set the mill near the prime conductor, 
and place the crooked wire so that its point 
may be directed towards the uppermost side 
of the great wheel A. Then turn the glass 
globe by the winch, and the stream of fire 
that issues from the point of the wire will 
turn the wheel, and consequently all the 
other working parts of the mill. 
Small boats or swans are sometimes made 
of light wood or cork, and they may be at- 
tracted and made to swim in any direction, 
by applying a finger towards them ; or they 
may have the addition of sails, and will 
then be made to sail briskly before an elec- 
trical gale from a wire held in the hand of 
the operator. 
A Every person knows that with his 
knuckle or finger, he can draw sparks from a 
conductor ; the further he removes his 
knuckle from the conductor, the longer will 
be the spark, and it will even resemble light- 
ning in the curves it forms, and its zig-zag 
appearance. 
There is even a mode of imitating the 
course of lightning by some conducting sub- 
stance, such as pieces of tin-foil stuck at 
different distances on a plate of glass, and 
sending a strong spark through them from a 
powerful conductor. In fig. 25 is a glass 
tube with pieces of tin-foil pasted on aWlif- 
ferent distances in a spiral direction, and 
hence called the spiral tube. It is inclosed 
in a larger tube, fitted with brass caps at 
each end, which connect with the tin-foil. 
V. hen the electric spark is made to pass, 
through this tube, a beautifully illuminated 
s P°t "ill be seen at each separation of the 
tin-foil ; and from the course in which the 
electric light Is attracted, will serve to give 
some idea, on a very diminutive scale, of the 
manner in which the lightning is attracted 
from one cloud to another. A similar effect 
will be produced'by the jar, fig. 26. 
A very pleasing effect is also produced 
from the electrical light, which lias been call- 
ed the diadem of beatification. The person 
who wishes to exhibit this experiment, binds 
his head with a band of silvered leather; and 
while lie stands upon an insulated stool is 
connected with the conductor by a metal 
chain. If then, while the machine is turn- 
ed, another person passes his knuckle or 
finger near the band of leather, it will ap- 
pear beautifully illuminated, and vivid 
flashes ot light will play about the person’s 
head who wears the magic diadem. 
It has been mentioned before that spirit 
of wine may be set on lire by the electric 
spark. The experiment is* easily made 
either by placing the ladle or spoon which 
contains the fluid upon the conductor, and 
taking the spark through the spirit ; or by 
a person holding the spoon or ladle in one 
hand, while lie stands on the insulated stool, 
having the other hand on the conductor. 
If then another person approaches the spoon, 
either with his finger or an iron poker, or 
other metal instrument, the spark will pass 
through the spirit of wine, and set it imme- 
diately in a flame. The experiment w ill suc- 
ceed better if the spirit is a little warm, or 
even if the spoon in which it is contained 
has been previously a little heated. 
4. W hatever may be the effects, however, 
of a spark drawn f rom the conductor, they 
are greatly augmented by wliat may be 
termed concentrated electricity, when the 
fluid is accumulated by means' of a Leyden 
phial, or a glass plate properly prepared. If 
a card is held dose to the coating of a char- 
ged jar near the bottom, and one knob of 
the discharging rod is applied to the card, 
and the other to the ball of the jar, the elec- 
tric fluid in passing through the card, will 
perforate it. I lie edges of the hole on each 
side will be a little raised, and the discharge 
will be attended with a sulphureous smeTk 
With a moderate battery a quire of the 
thickest paper may be perforated in the 
same manner. 
If a small chain is laid upon a piece of 
white paper, and a shock from a Leyden, 
phial is made to pass through it, the paper 
will be stained with a blackish tinge at every 
joint of the chain ; and if the experiment is 
made in the dark, the chain will appear il- 
luminated, with a kind of radiation at every, 
juncture. 
By a strong shock of electricity, metals are 
melted, and gold itself may be incorporated 
with glass, so as to give the latter the co- 
lour and appearance of that metal. T he ex- 
periment is not difficult. All that is re- 
