Evening star., 1948-09-10
Stars, Men end Atoms
Lowest Of Temperatures
Is Achieved at Leiden
Researchers at Dutch University
Approach Absolute Zero
By Thomas X. Henry

By Thomas X. Henry
What b believed 10 Be the lowest tempera.
turs ever reached On sarth-four thousandths
Of . degree above absolute sero-has been
attained at the University Of Leiden In Hol.
land.
This has just bssn reported 10 the once of
Naval Research BY Capt. James p. Clay. tt
European representative. Absolute sero is
minus 45o.s degrees Fahrsnheit IT b the point
where au molecular motion stops and hence tho
eoldest conceivable.
For the past 20 years Leiden has bean world
center Of low temperature Investigations. The
laboratories were closed by the Germans dur.
ing the war, but the equipment has been 70.
assembled. Capt. Clay reports. and the work
resumed on An even more ambitious scale than
before = It now has become oe much more
than theoretical importance with the discovery
that some materials become perfect conductors
OF electricity in the temperature range Of
l or degrees above absolute zero. It also
is important in fundamental studies Of the
structure Of the atomic nucleus
Among the recent accomplishments at
Leiden. he reports. Is . 5,o00-fold concentration
OF the light tsotope Of helium. Hs. This Is
found mixed with ordinary helium in nature
In ratio Of about one to . million. It's atom
Is one neutron lighter than that Of the nom
explosive gas. second nghtest element In the
universe, which originally was discovered in
the sun and which has become Of outstanding
Importance in nuclear research.
The extremely close approach TO absolute
zero attained In the Leiden laboratory, Cant,
Clay reports. Il accomplished In three major
steps, Temperature Of about degrees abso.
lutte u reached by svaporating liquid helium at
ordinary atmospheric pressure. This is brought
down to slightly above degree absolute by re.
ducing the pressure over boiling helium From
this point on progress is extremely difficult
and involves the use Of extremely powerful
magnets.
The bottom OF the Atlantic Ocean Is q rourh
country.
Both east and west Of the great underses
mountain range which extends down the
middle Of the ocean from Iceland to the Ant
arctic the general contour might be compared
to the Dakota Badlands. according to the nnd-
tnss Of the Swedish deep-sea exploring ship
Albatross.
Sent out by the oceanogrifska Instituted Of
the University Of 0oteberg under command
Of DR.. Hans Peterson, the ship with its crew
Of scientists has completed one Of the most
extensive surveys ever made Of the ocean
depths. Much use was made Of differential
echo soundings. Two echoes are received from
the bottom. One Ii from the basic rock, the
other from the top Of the sediment which has
piled up on top of them through the mil
leniums. In this way 1t Is possible to measure
the depth Of these sediments and make calcu-
lation Of the time required for their accumula-
ton.
East Of the mid-Atlantic Ridge, the Swedish
scientists report, this has been very long In
deed. They are piled up from $500 to 5000
feet above the rock bottom. They accumulate
only at the rate Of fraction Of an inch year
from the bodies Of sea organisms dust and ths
like which sinks to the bottom.
The accumulation, they conclude. must have
been in relatively undisturbed process for many
millions Of years. Nowhere has 1t been ut an
even rate. however, and there Is nothing that
could be remotely compared to q prairie under
the sea. West Of the ridge for some unknown
region the accumulation of sediment has been
somewhat slower, or has been in progress .
shorter time The depth above the basic rock
is from 1000 to 400e feet. The surface, how
ever, remains just as rough. In the Caribbean
the sediments measure from 800 to 1000 feet
and the bottom Is extremely rough.
Proceeding into the Pacific. the Abatross
party found considerably shallower sediments,
seldom exceeding 800 feet In thickness. There
were many areas Of exposed rock. pointing to
volcano eruptions at great depths In recent
timex