The Sun.
London, England, 1857-01-06 00:00:00

_ROYAL INSTITUTION.

Professor Faraday delivered the fourth lecture of his
present course on Saturday, the subject being " Electric
Attractions." He commenced by observing that the various
kinds of attraction he had previously noticed are constant
in their actions, but the attractions now under considera-
tion aro only exerted under certain conditione, and they are
changeable, and may be transferred from one substance to
another. The attraction of light paper cylinders by excited
rods of glass and of shell lac, which drew the cylinders
after them along the table, was the , first illustration of
this kind of attraction. He then showed the influence
of exciteci electrics on a suspended hollow paper sphere
made of rings of stiff paper placed transversely within
each other, so as to form a light spherical body conve-
nient for experimenting with. In the first instance the
sphere and glass rod were shown to possess no apparent
attraction to each other until the glass was rubbed with
silk ; and then, after attracting the sphere, and thus com•
municating a portion of electricity to it, the opposite con-
dition of repulsion was produced between them. Professor
Faraday exhibited the excitement of electrical attraction
in a variety of ways, and showed that in many ordinary
actions electricity is excited, though we are unconscious of
its presence. In moving the feet on a carpet, and in
brushing and combing the hair, for instance, electricity is
excited, of which he presented illustrations. By rubbing
his feet on a piece of carpet whilst touching the top of a
delicate electrometer, 'the gold leaves diverged when he
withdrew his hand; and a long lock of hair was made highly
electrical on being combed. Professor Faraday stated that
by combing a lady's hair when she waa standing on an insu-
lating stool, constructed of four inverted glass tumblers,
with a book resting on the top, sufficient electricity was
excited to admit of sparks being emitted from her body.
The friction of two silk ribbons, by drawing them through
a piece of flannel, was shown to produce decided electrical
phenomena, which were still more strongly exhibited when
two strips of gutta percha were similarly treated. Having
exemplified the excitement of electrical attraction by vari-
ous kinds of manual friction, the large plate electrical
machine of the Royal Institution was put in action, after
its structure had been explained. The history of that
particular instrument is rather peculiar. It was one of
two made by Montgolfier for the Emperor Napoleon L,
which was brought over to this country and bought for
presentation to the institution. Though many years have
elapsed since: t was made, it is in pointt cf efficiency
nearly equal to the best modern plate machines of
the same size. In directing attention to the powerful
spark drawn from the prime conductor of this apparatus,
Professor Faraday observed that it was exactly similar to
the sparks obtained on rubbing a stick of sealing-wax on
the back of a cat ; every one, indeed, knew what an elec-
trical spark was, except the philosopher, to whom it re-
mains a thing inscrutable, for of its nature nothing is really
known. Electricity, he said, appears to be the most spiri-
tual and one of the most important of the attractive forces,
though scarcely any of its phenomena were known till the
middle of the last century. With the aid of th% machine
several electrical phenomena were exhibited ; some show-
ing, on an enlarged scale, the actions of attraction and re-
pulsion, the intimate relation between which apparently
dissimilar forces, however, was not explained ; as well as
other experiments not directly bearing on the immediate
subject of the lecture, but exemplifying different manifes-
tations of electricity. The beautiful luminosity of the
electric discharge was shown by transmitting the charge
of a Leyden jar through the links of a suspended chain
and through a row of eggs, also by passing sparks ,through
a long exhausted tube. Its heating power was illustrated
by the transmission of a spark through a long insulated
wire to some gun cotton, which it exploded. Professot
Faraday observed that though the great blast of gun-
powder at the Round Down cliff at Dover was effected
by voltaic electricity, yet most of the blasts inthsl
chalk
rocks, in constructing the railway between Folkestone
_
and Dover, were exploded by sparks from a common elec.
trical machine.
lecture, at the conclusion of it shook hands
The Prince of Wales, who was predseen:itdhurrirnegfestshoer
Faraday.