The Sun.
London, England, 1822-09-26 00:00:00

FOR THE SUN.

MR. EDITOR—Be pleased to insert the fol-
lowing in your Paper, and you will much oblige
Your humble Servant,
A CORRESPONDENT.

OBSERVATIONS on CONDUCTORS for LIGHTNING
on Board SHIPS, and on the STRENGTH of IRON.

THE SUN Newspaper, of Wednesday the 10th inst. men-
tions an experiment having been tried at Plymouth, to convey
the Electric Fluid down the masts, and through the keel to
the water ; and the account further states that the present
mode of conducting the electric fluid is by a chain kept in a box,
which is only hoisted up when wanted. This is not the fact,
for ships have carried them at sea, in the vicinity of land, for
months together. The pointed wire, at the end of the chain,
was higher than the truck at the main top-gallant mast head,
and secured by a lashing under the truck ; it led down abaft
the mast, and was secured above the rigging by a lashing, and
was led by further lashings down the top-gallant back stay
into the chains, and was stopped to the chain plates, and hung
down the side of the ship into the water. it was therefore
clear of the men employed in reefing and furling sailS, &c.,
and would conduct any lightning clear of the ship. This
chain is sufficiently strong ; and the late immortal navigator,
Captain Cook, had one of these conductors up in Batavia
Roads',and his ship was in consequence, during a thunder-storm,
the only ship there that escaped being injured by lightning.
It is proper here to observe, that lightning is not frequent at
sea, except in the vicinity of land. A conductor on shore will
save a house from the effects oflightning, but will not insure
the lives of those in it, because the quantity of electric matter
may be so great as to destroy every one near it. There is
such a thing as ascending electricity or lightning, as well as
descending. Suppose them to meet in a ship, what an explosion
there would be. When an irruption of a volcano happens, the
lightning is dreadful. This is ascending lightning, and a proof
of there being such. Farther at sea, in a dark night, and a heavy
gale of wind at south, a meteor rises tip the rigging, and
remains fixed at the mast-head during the height of the
gale.: when the gale abates, rain always bnsues': and the me-
teor disappears ; because, being electric, the rain conducts it
imperceptibly down again to the sea, from whence it first arose :
the ship's bottom being the conductor. The experiment tried
at Plymouth has great merit, but without any disparagement
to it, the safety of a -ship and the crew in a thunder storm
depends chiefly on the lightning being kept clear of the inte-
rior of the ship. An experiment was lately made at Ports-
mouth to break the shanks of two anchors made by ()Teat and
small hammers. If the shank of a moderate sized anchor
is broken, the inner bars appear a little twisted, and the smith's
coals are sometimes found amongst them. What must be the
case in anchors of the largest size ? The strength of a human
being is not equal to weld the iron bars of such an anchor.—
In consequence of this, a Captain of the Royal Navy asked the
late Mr. Bolton, of Soho, near Birmingham, if he could in-
vent a machine to go by steam that would execute all the iron
work of the dock-yards ? His reply wa_ ,S that he could :' and
that it would weld the bars of the largest anchor into one
solid mass of iron. That the French for their heavy iron work j
made use of water wheel forges to render the iron stronger.
In the year 1794 all the smiths (one excepted) ceased to work
at Chatham dock-yard, and their numbers were not replaced
under two months' time. This shews the difficulty of procur-
ing smiths in time of war, and a machine to go by steam with-
out injuring our population will diminish the hard labour of
the smiths ; for their work would only consist in heating the
iron and putting it under the proper hammers. The iron work
of a ship is often not sufficiently hammered, in consequence of
which, when the ship is in commission, the annouxer's forge is
constantly at work, when the weather will admit of it. The
machine of Mr. Bolton must have rendered the iron work
stronger, and the armourer's fbrge would not have been always
in requisition at sea.