The morning news. [volume] (Savannah, Ga.) 1887-1900, 1896-02-16
A VAST AND DEADLY MAGNET.
WASHINGTON DAVIS PROPOUNDs 4
NOVEL AND INTERESTING
DEVICE.
Biz Magnets ira our Harbor-BattIe-
ships 20 Re Crippled by Their Ac-
tfon-Chargcd al VIII From the
Shore-ViervS Of Prof. HaIIock.


New York Feb. $50 many people have
been talking and thinking within the past
Few weeks. and even nervous about the
ways and means Of defending the coasts
or the Omitted States against attack by a
foreign power that tho progress Of e'cc-
trical experiments in ibis matter may Doe
OF interest.
Since the la~t war iU which the United
States was al an practicalIy Interested, APP
piled electricity has done SO much 60
change the methods OF communication
and looomotion both on land and sea that
more may be expected from it. We had the
Atlantic cable in 1865. which CONDENSED
weeks into days. as far as commerce IS
concerned between the old world and the
new: also the telephone which cuts inIo
the mail methods for moderate distances,
shortening the time of supply from days
to minutes; then the street trolley car,
which is an example of machinery pro-
PEELED by electricity that has so greatly IA
cHitated the transportation of passengers
and mails in cities-to say nothing of the
electric light. All of which is applied cleo
tricity.
out of what was at first mere idle curl
osity. I took the trouble TO find out how
far electricity can be relied upon as an aid,
or a single factor in defending our coasts
and harbors. and the result IS mere gwen
In November, 1884 Col W. r. King,
then commanding engineer at the United
States engineering school at WilleJs
Point, on Long Island, tried 10 see now
powerful a magnet he could make, ana
of what use il would be. lie took the
largest steel cannon he had Noi which
Il is unnecessary 10 give the dimensions
here, plugged up the muzzle with soft
metal, then wrapped the barrel with cop
per wire thereby making an instru-
ment that could be greatly magneuzed
by a current Of electricity. When the
current was turned on. all small pieces OF
iron lying near the cannon began to leave
their places and cling TO the great mag
net. a man took dinner tray loaded with
pieces of scrap iron weighing from an
ounce to a pound, and when he was with
an l00 feet of the magnet. the nieces began
TO leave the tray ana clluE 10 the cannon,
atHa a little nearer The platter was as
Clean rs that fOt Jack Sprdt and his wife
after they were through eating. Next
crow bar weighing twenty-five pounds was
taken near the cannon. 1t neW out OF
the mans hands and stuck with such force
that two strong men were required 10 pun
IL away, and this could be done then only
by a sudden jerk.
1t was noticed also that the magnetic
comIasses in the immediate ucighbOrhood
were apprecaEly depleted by This, the
greatest magnet i'm the world. Some news
paper reports at the time quoted Col King
as saying that a ships compass could be
dehectcd six miles at sea; but this was an
injustice To the colonel. and herewith is
given am extract fl ON "a private letter
written by him at the time, to show what
was really done. After dcprecatng the
wrong statements by certain newspapers,
Col King wrote.
III. s Engineering School, Wincts
Point POI Queens County n. y. N2v 2,
be of interest to you TO know exactly
what the effect IS on the needle and this
] had carefully tested just before yOur let
ter came. viz, at distances of 50, 100, $50
and 200 feet. In a line nearly east and west
through the magnet, the delections of the
compass We're So degrees, IL degrees, s de-
grees, and Pc degrees, which shows the
rate at which the force tapers on, so to
speak.
pictures recently taken, showing the mag
net holding up five 320-lb projectiles, and
how the force will pass through man
and cause iron to stand out from his body,
like quilts upon the fretful porcuptne.
Respectfully, W. r. King"
The pictures show a number of large
spikes attaching horizontally TO the body
OF man standing near a magnet
To illustrate the practical use Of the
force in this great magnet as il might
be applied to coast and harbOr defenses
al New York and other places. l shall
give the result of a talk with Prof w.
Hallock, of the department of natural
physics, Columbia College in relation to
the effect that a combination of these
great magnets might have upon battle
ships approaching harbors and coasts.
Il know of Col. Kings great magnet.
The magnetic power in II could not be
transmitted through copper or any kind
OF wire running out from the shore TO
small receiving magnets lying at the bot
tom of the channel entrance to a harbor,
because the currents slope off, as ii were,
into air or water as they proceed from the
great magnet. thereby losing force. But
there is nothing TO hinder the planting of
a line of these great magnets across the
entrance TO a harbor several miles at
sea, and magnetizing them through cables
from the shore at short notice. They could
be sunk to the bottom of the sea, and would
act just as efficiently under water as on
For Instance, take the entrance to New
York harbor The chart here, as you see,
shows that the channel is very narrow,
and that is one great advantage IL we
should take a few old cannon barrels ana
make magnets of them like Col, Kings,
they could be dropped in line across the
channel a few hundred feet apart and
here and there around Sandy Hook con
Meeting them each with powerful bat
terry on shore. The apparatus would be
comparatively inexpensive and simple.
Each one would be what we call a tenn
porary magnet, that is one which could
be magnetized temporarily by a current
of electricity transmitted through the ca
Bile from the shore. A permanent mag
net, OF one retaining constant power,
could hardly be made large enough to be
efficient, and if it We're, its constant force
would endanger all incoming vessels all
the time. But q magnet, or line of mag
and made active in a minute and the
current could be shut off as quickly The
power of the magnet would depend upon
the strength of the current received from
the shore.
Now, suppose a battleship We're COM
ing up the channel into New York harbor
The ship is made almost entirely Of iron
and steel The line of great magnets
lying under and across its Roadway. could
ce powerfully magneuzed When the
shin approached within two hundred feet
Of a magnet, the latter would leave it's
bed and cling TO the forward keel ana
If the ship should pass directly over one
Of the magnets, the depth of water below
the keel is SO slight that the magnet
would come up 10 the ship with great
force. Having once touched the keel. the
electric current from the shore would
either stop the ship, or the magnet would
be dragged along the keel until it would
strike the propellers, which would be done
with such force as to crush them.
In case the first magnet should not be
strong enough, and the ship should cross
q second, the second would seek the end
of the ship opposite the first, forming
the two poles and magnetizing the entire
ship. Then il would be impossible for the
ships steam power 20 overcome this force.
while all movable iron would be stuck
solid.
An this is very plausible and could be
made practical OF course what is done