New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1914-06-07
Leyden Physicist Discovers
a Possibly Permanent
Electro-M Magnet.
RESISTANCE ENDS
ALLOW TEMPERATURE
Lead Coil in Liquid Helium Main
taius Current Without Elec-
trio Connection.

Professor II. Kammerlingh Onnes. OF
Ieyden University. who received the No
bel prize in physics last year, has demon
strated the maintenance of a permanent
electric current. with no potential force
TO drive il, in a coil OF wire in which the
power OF electrical resistance in the metal
had been reduced 10 nil, according TO a
report from Holland.
The reports have created intense inter
est among scientists, for the discovery
suggests TO the electrical world what the
possibilities of perpetual motion or me-
chanical friction reduced 10 zero would
mean in other fields.
When the subject was called to the at
tention OF Professor George B. Pegram.
o. the department of physics of Column
ba University. he said Professor Onnes
perhaps was the most likely man 10 aC-
complish this scientific marvel, in view
Of his painstakinC experiments in the
same direction in the past There are
only two or three laboratories in the
world possessing the facilities for the
perfecting Of such experiments, and one
Of them is at Leyden.
The commercial possibilities Of the dis
covory cannot he considered as yet, be-
cause Of the large expense involved in
reducing metal coils TO a point of zero
resistance However. Professor PeSram
pointed out that il the electrical resist
ance in copper wire could be reduced by
only a small percentage it would mean
the saving Of millions Of. dollars.
Professor Pegram said the reported ex-
pertinent would prove interesting 10 scien-
usts in working ont to the last degree
the principle that the electric resistance
OF metals decreases propOrtionately as the
metal is reduced 10 a low degree Of tom
pcratre.
Professor Onnes's discovery shows that
the electric resistance of metals vanishes.
or becomes zero, if they are cooled TO the
temperature OF liquid helium. Tho lque-
Gcation Of this rare gas by the same in
ycstiCator was in itself a remarkable
achievement. for it enables scientists to
study the properties of matter at tenn
perature Of only Is degrees above abso-
lutte zero, or 271 degrees below zero cent?
grade.
The apparatus in Professor Onnes's
latest experiment consists of coil of 1905
turns of fine lead wire, the ends Joined
together and the whole immersed in liquid
hclium. A current Of half an ampere
circulates in the coil and if a compass is
brought near the needle at once points
toward the coil. for the coil is an electro
magnet, a permanent electro-magnet,
without a battery or other current gem
orator.
The current was started in the coil by
induction, and as the wire has no resist
ance il continues 10 circulate, for the
same reason that tho planets circulate
about the sun At the end Of four and
half hours no decrease could be detected
in the strength Of the current, and it
might continue indefinitely for all that
is vet known.
The method OF starting the current was
as follows: The coil was placed in a glass
tube. surrounded by a second tube CON
tanning LIQUID hydrogen and mounted be-
tween the poles of an electromagnetic.
The magnet was next excited. inducing a
current in the coil, which immediately
died out. owing 10 the electrical resist
ance OF the wire. The liquid helium was
then introduced which cooled the coil to
tho point at which its electrical resistance
became zero The electromagnetic was
turned off and removed TO distance, the
destruction Of tho magnetic field inducing
Il. current again in the coil; but this time
the current persisted, the coil OF wire be
coming at once permanent magnet.
PHYSICISTS have often employed the con
,.option Of electrical currents rotating IT
molecular circuits devoid of resistance e
evnlaip the phenomena Of magnetism, and
i'm Professor Onnes's experiment theS
have at last a large scale model or sucf
circuit.
Professor Onnes in short, has made pos