The Butler County press. [volume] (Hamilton, Ohio) 1900-1946, 1913-08-15
SLOW COOLING KEEPS 1T SOFT

Yet the Busy Brain of Man Cannot
Snoosed In Reasoning Out Why This
10 So-The Mysterious Properties
Exhibited by Water, Tin and Glass.
Here is fact. known to every body,
the actual appearance OF ghost, by
which | mean that the fundamental ex-
planation OF the phenomenon is about
as far beyond our reach In the one
case as In the other
The fact to which | refer Is the pro-
duction OF tempered steel by quenching
In cold water. If hot steel is cooled
very slowly 1t becomes soft and cannot
take cutting edge. but IL ii is cooled
suddenly Ii becomes very hard and can
be ground into keen swords, knives
and cutting tools.
Now why the difference? Have you
ever thought about that question? Ii
you have not, many man of science
has, and has been puzzled over 1t.
Here Is another related mystery. Ii
you heat an old japanese sword. which
for centuries has retained its capacity
TO slice of head at a blow. or to
open swift passage for the soul OF
the victim Of the harakiri mania, to
the temperature OF boiling water 1t
gradually softens and loses the keen
ness that once made 1t so formidable.
1t Is the same steel, but IL. too, seems
to have lost it's soul At a tempera-
ture OF $50 degrees centigrade the
hardened steel commits harakiri In
few minutes Surely there Is some
thing strange In that
Then consider this At zero tempera-
ture water changes from liquid and
suddenly becomes solid But If you put
the water In vase and carefully pro-
tect 1t from dust you may cool 1t as
much as 20 degrees below zero and yet
Ii will not freeze, But now shake the
vase or drop in bit OF Ice, and the
water Immediately soidifies.
| owe the collection Of these facts to
q paper by Professor James II. Wal
ton, Jr., OF Wisconsin university The
explanation which he gives is that sub
stances like the hardened steel and the
unrreeZing water are in a state of
suspended change" That accounts
for the phenomena but IN a certain
sense they remain mysterious, just as
life Is mysterious.
Many substances possess the same
curious characteristics Professor Wal
ton says that II flask containing So
dium acetate, which has been cooled
below its natural freezing point with
out solidifying. is opened in room
containing dust Of the solid acetate the
fine particles OF the latter dropping into
the flask will cause the whole contents
TO soidify
Tin Is Il very strange metal with re-
gard TO this state OF suspended change
or ''metastability A severe winter cold
will sometimes cause it to lose its
hardness and crumble.
Objects made OF tin sometimes un-
dergo such change and are then said
TO be suffering from 'the tin disease"
The contact of diseased" tin with
bright. hard tin is capable OF setting
up the transformation.
Glass. Professor Walton informs us.
is IAN undercooled substance" that Is.
IL is In a metastable condition IL old
glass tubes through which water has
frequently passed are heated the glass
crystalliZes and loses its transparency
All substances in this state are LA BILE
TO change. and the change. under prop
CT conditions, may be sudden. Hard
ened steel is In a similar category Ii
IL were az perishable as tin 1t could not
be safely used for many purposes for
which II is habitually employed. For
tunately steel exhibits great resistance
TO change OF state after it has been
tempered Transformation Is retarded
or arrested
Does steel slowly return to the sta
BILE form and thus grow softer?" asks
Professor Walton, and then answers;
That We do not know; we can only
say that If such change does take
place. hundreds or years are necessary
10 bring 1t about.
The same ancient japanese swords.
which, when heated as before describ-
ed. become soft. retain all their hard
ness IL carefully preserved
1t Is evidently of the highest i'm
portance TO the practical world that
science Is investigating these things
cumstances In which the changes come
about, even II Ii has not unveiled the
underlying mystery Of their cause
Garrett P. ServIss In New York Jour
nal