The Olneyville times. (Olneyville [Providence, R.I.]) 1887-1917, 1913-08-22
BATTLES SCIENCE.
Why Hot Steel Is Tempered by
a Sudden Cooling.
SLOW COOLING KEEPS 1T SOFT
Yet the Busy Brain OF Man Cannot
Succeed In Reasoning Out Why This
ls So-The Mysterious Properties
Exhibited by Water. Tin and Glass.
SLOW COOLING KEEPS 1T SOFT


Here is a fact. known TO everybody.
which is as mysterious as would be
the actual appearance Of a ghost by
which | mean that the fundamental ex-
planation OF the phenomenon Is about
as far beyond our reach In the one
ease as I'm 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 II becomes soft and cannot
take a cutting edge but If 1t Is cooled
suddenly IL becomes very hard and can
be ground into keen swords. knives
and cutting tools.
Now. why the difference? Have you
ever thougbt about that question? If
you have not many man OF science
has. and has been puzzled over IL.
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, 10
gradually softens and loses the keen
ness that once made It so formidable
IL IL the same steel, but IL, too. seems
to have lost It's soul. Al tempera-
ture OF 100 degrees centigrade the
hardened steel commits harakiri In
few minutes Surely there Is some
thing strange I'm that
Then consider this At zero tempera
ture water changes from a liquid and
suddenly beCoaes solid. But If you put
the water I'm vase and carefully pro.
tect IL 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 I'm a bit OF Ice. and the
water Immediately solidiics!
owe the collection of these facts tO
n paper by Professor James H. Wal.
ton. Jr.. OF Wisconsin university The
explanation which he gives is that sub
stances like the hardened steel and the
unfree2ing water are i'm state of
"r~pended change" That accounts
for the phenomena. but in certain
sense they remain mysterious. just as
life IL 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 I'm room
containing dust Of the solid acetate the
fine particles OF the latter dropping into
the flask will cause the whole contents
TO solidify
Tin IN u very strange metal with re
gard TO this state of suspended change
or "metastabllity." A severe winter cold
will sometimes cause II To lose its
hardness and crumble
Objects made OF tin sometimes I'm.
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 "an undcrcooled substance Is.
IL is In mctastable condition II old
glass tubes through which water has
frequently passed are heated the glass
crystallzes and loses Its transparency
All substances i'm this state are liable
to change, and the change under prop
or conditions, may be sudden. Hard.
encd steel Is I'm similar category, II
IL were as perishabe ms tin II could not
be safely used for many purposes for
which IL is habitually employed For
tunately steel exhibits great resistance
to change OF state after II has been
tempered Transformation is retarded
or arrested.
"Daes steel slowly return TO the sta
BILE form and thus grow softerY" asks
Professor Walton. and then answers:
THAT we do not know; we can only
say that II such change does take
place hundreds OF years are necessary
TO bring IL about"
The same ancient japanese swords,
which. when heated, as before deScrib-
ed. become soft, retain all their hard
ness II carefully preserved,
IL is evidently of the highest Inn
portauce to the practical world that
science is investigating these things
and discovering the way and the cir
cumstances I'm which the changes come
about. even II Il has not unveiled the
underlying mystery OF their cause
Garratf u SprVisS I'm Now York lour