MACHINE, ELECTRIC. 
^ill be long, crooked, and less sounding ; if 
the breadtli be still more diminished, the 
coudnctor begins to come under tlie deno- 
mination of a pointed body, the electric 
matter passes to it from the prime conduc- 
tor, through a great space of air, with a 
liissing or rustling noise, and in a continual 
stream : a still greater sharpness enables 
the electricity to pass over a greater space, 
but silently, and nothing is seen but a small 
light upon the point. If a similar point 
issue from the prime conductor, and the un- 
insulated conductor be round and polished, 
the same effects happen in like situations ; 
but if both be pointed, the electricity is 
more readily discharged : and in all these 
cases the appearance of the electric matter 
at the point of the prime conductor will be 
that which is peculiar to its electricity, a 
large divergent cone, if positive, or a small 
globular light or cone, if negative, and the 
light at the point presented to tiie prime 
conductor will be distinctive of the con- 
trary electricity. Whether a pointed con- 
dilctor be electrified positively or negative- 
ly, if the nose be brought near the point 
during the electrization, a wind will be felt 
blowing from the point, and the sense will 
be affected with a sulphureous or pbospho- 
real smell. 
The reaction of Ihe force by which the 
air is put into motion, is exerted on the 
pointed body. This is shewn by a pleasing 
experiment with an electrified wire ; thus, 
to the middle of the wire, or rather between 
two wires that lie in the same line, is affix- 
ed a centre-cap like those used in sea-com- 
passes, so that the wire may easily be mov- 
ed on a point in a horizontal direction, as 
magnetical needles are : and the ends of 
the wire are pointed and bent contrary 
ways', to point in the direction of the tan- 
gent to the circle described by them. Now 
if this wire, thus suspended on a point, be 
insulated and electrified, its sharp ends will 
become luminous, and it will revolve in a 
direction contrary to that in which its ends 
are bent ; or if it be suspended on an un- 
insulated point, and brought near the elec- 
trified prime conductor, the same effect will 
follow. 
It may be thought strange that the air 
should issue from an electrified point, 
whether its electricity be positive or nega- 
tive. It is easy to conceive that the issuing 
out of the electric matter may cause the air 
to move in the same direction ; but it ap- 
pears odd, that the electric matter rush- 
ing towards a point should cause the air to 
move directly contraiy, that is to say, like- 
wise from tiie point. If, however, the cir- 
cumstance be examined more narrowly, the 
difficulty will vanish. For it is highly pro- 
bable that the electric n)atter passes too 
swiftly to excite any motion in the air, but 
that undulation wherein sound consists ; to 
which may be added, that if the electric 
matter do act on the air to put it in motion, 
the air must react with an equal force; and, 
therefore, that a current of air blown 
against the course of the electric matter 
must affect its appearance, by retarding 
the rays and, deflecting those against which 
it struck obliquely : the contrary to which 
is, by experience, known to obtain ; for 
the luminous cones are not sensibly affect- 
ed by such tr.-atment. The air being thus 
indifferent as to the motion of the electric 
matter, its motion may be shewn to depend 
on the established principles of electricity. 
The, point is electrified either positivel/bk 
negatively, and the air, immediately oppo- 
site and contiguous to the point, must, by 
the emission or exhaustion of the electric 
matter, become strongly possessed of an 
electric state of the same kind with tliat of 
the point : it is therefore repeiJed and re- 
placed by other air which is also electrified 
and repelled, by which means a constant 
stream is produced blowing from the point, 
and that equally, whether the electrization 
be positive or negative. And, the point 
repelling the air must itself also be equally 
repelled in the contrary direction ; whence 
the horizontal wire above described is turn- 
ed, and that always one way, namely, con- 
trary to that in which the air is moved, or 
to the direction of its bent points. 
If an insulated conductor,- free from 
points, be brought within a certain distance 
of the prime conductor or cylinder in an elec- 
tric state, it will also exhibit signs of elec- 
tricity of the same kind ; but if tliose signs 
be removed, by taking the spark, and the 
conductor taken from the prime conductor, it 
will exhibit signs of the contrary electricity. 
This is a very remarkable appearance, but 
may be accounted for, if two suppositions 
be admitted, viz, first, that the electric mat- 
ter is attracted by conducting bodies; and, 
secondly, that the parts of the electric mat- 
ter mutually repel each other, the forces of 
each power being in a certain inverted 
ratio of tlie distance. 
For the electric matter, in an insulated 
and uniform conductor, will then be equally 
diffused through its whole mass, and the 
attraction which that conductor will exert 
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