The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1839-06-04 00:00:00

BLOCKADE OF BUENOS AYRES.

In answer to an application from Liverpool, with reference
to the lately-reported intention of the French to raise the
blockade of Buenos Ayres, and to arrange their differences
with that republic, through the good offices of this country,
the following letter has been received there from the Foreign
office :

" Foreign-office, May 25, 1839.
" Sir,—l am directed by Viscount Palmerstown to ac-
knowledge the receipt of your letter of the 22d. instant, and
to acquaint you, in reply, that her Majesty's government have
not been informed that the French government have deter-
mined to raise the blockade of Buonos Ayres, or to adjust
their differences with the government of Buenos Ayres
through the mediation of Great Britain.—l am &c.
" J. BACKHOUSE."

LIVERPOOL MECHANICS' INSTITUTION.

LECTURES ON ELECTRICITY.

On Wednesday evening Mr. Addams delivered the fifth
lecture of his course.
We have now to consider that portion of our subject which
applies to electro-dynamics, a term which implies the motion
and force of electricity. For this purpose we employ a
voltaic battery, from which to derive our electricity, and
make the communication with the different apparatus by
dipping the two wires of the battery into cups filled with
quicksilver, from which are led to the apparatus of experi-
ment. The quicksilver is merely employed as a ready means
of causing a good connection between the metals. When
two currents of electricity pass along in the same direction
they will attract each other ; but if one current be passing
in one direction, and the other in an opposite one, then they
will repel one another. This was beautifully illustrated by
the lecturer, by means of two wires, the one stationary and
the other moveable, which were made to approach or to re-
cede as the direction of the current of electricity was varied.
M. Ampere makes this experiment the foundation of his
beautiful theory of magnetism. _ This theory will be found to
hold good, whether the wires or conductors be parallel or
diverge in an oblique manner, provided they set off from the
summit of an angle in the same direction ; but if they pro-
ceed in different directions from the summit of the angle,
and one of the currents be going to and the other coming
from, they will invariably repel each other, whatever may be
the measure of the angle.
If copper wire, covered with silk, be coiled round a card-
board cylinder, and the apparatus be then poised upon a
pointed centre, it will be found, when voltaic electricity is
communicated to the helix, that it will possess every pro-
perty of a magnet. This experiment by Joseph Ampere
proved that the magnet is possessed of polarity, in conse-
quence of currents of electricity revolving about it, its
length being the axis. If I make electricity run through a
piece of metal, or oven charcoal, by means of wire coiled
spirally round it, the body exhibits the properties of the
magnet so long as electricity runs through the wire. One of
the first experiments of Professor Oxsted in magneto-elec-
tricity, was the transmission of a current of voltaic electricity
across a magnetic needle, by which the magnet was turned
out of its true direction ; and upon this principle the galva-
nometer, consisting of two fine astatic-magnetic needles, is
constructed, by which the most delicate and appreciable
current of magnetic electricity can be readily detected, as
well as its direction.

To-morrow evening Mr. Addams will consider the theory
of terrestrial electric currents, by which the variation and
dip of the magnetic needle are accounted for, and will enter
upon the science of Thermo-electricity, elicit electric sparks
thereby, &c.

REDUCTION OF FARES.—The fares by the steamers ply-
ing between Douglas and Liverpool, will on and after Mon-
day next be reduced to 7s. the cabin, and 3s. steerage dyeing
the summer season.—Manx Liberal,