The daily Cairo bulletin. (Cairo, Ill.) 1878-1???, 1884-05-13
The Older Electric, ty.

Prof. Tyndall delivered his third
royal institution lecture on The Older
Electricity, its phenomena and investi-
gators before fui lEeatcr. He
began with some supp emontary re-
marks and experiments illustrative OF
induction, on which Epnus, rs he
showed, had shed good deal of light.
IL was next demonstrated that the
charge of conductor depended upon
its surface, and not upon its weight.
Monnier proved this. He found that an
anvil weighing POO pounds gave a
smaller spark than n speaking-trumpet
weighing 10 pounds. lie Roi and
Darcy observed that hollow sphere
accepted the same charge when empty
as when filled with mercury,
The lecturer illustrated the perfect
efficiency of hollow conductor by the
experiment of suspending hat from
silk strings. Electricity was poured
into the hat, but produced no effect on
the electroscope, the two gold leaves
of which, however, flew asunder the
moment the nap of the hat was cleo
trifed, proving that all the charge was
distributed upon the surface. He re-
peated also the demonstration devised
by Franklin, who placed long metal
lie chain in silver teapot, which he
electrified. Then connecting the tea
pot with an electroscope he produced
divergence, but on lifting the chain by
a silk string the electricity spread in
part over the outside of the chain, and
the divergence was very sensibly d.
minished.
Faraday built himself a chamber of
laths covered with paper and wire
gauze, and suspended it by silk ropes.
Within this chamber no trace of cleo
tricity could be detected, while from its
outside edges and corners the electrici-
ty streamed vehemently into the air.
The importance of the electric action
of points, as Illustrated experimentally
by Franklin, who afterward turned
that action into such momentous ac-
count in his invention of the lightning
conductor, was next adyerted to.
The lecturer retraced the Ameri-
can philosophers reasoning, and justi-
fed his deductions by corroborative
demonstrations, pointing triumphantly
to the electroscope charged with a
point. The fluid passed through his
own electrified body, through the
needle he held in his hand, and out at
the steel point swift as lightning to
the delicate index of action. OF course,
as the live conductor, he was standing
on the Insulating glass-legged stool.
His electrical condition was plainly
enough shown by the paper thongs,
yards apart, of the mimic whip in con-
nection. Then, as he stopped down
from the stool, they fell fabbily
enough, thus demonstrating the instan-
taneous discharge of electricity by n
point. There followed the electrified
ton Of the air in the theater by a
point
The electricity was next carried off
at point through the discharging
power of flame. Prof. Tyndall here
remarked that by the discharge of
electricity from surrounding point the
air became electrified; it became as a
consequence self-repelled, that per-
ceptible wind" was felt when the
hand was brought near point whence
the electricity thus issued. 1t was on
this principal Hamilton founded his
electric mill, which the lecturer forth
with showed in action. A pretty ex-
pertinent which followed was often
performed by Faraday. 1t was the
fusion of sealing-wax under the action
of electricity, which caused it to shoot
forth in lorg filaments of extreme DEL
icacy and beauty. London Times.