The daily morning journal and courier. [volume] (New Haven, Conn.) 1894-1907, 1905-08-07
THE ABSOLUTE ZERO.

The confusion which often exists
about the term zero necessitates a
word of explanation. In graduating a
thermometer two points are taken as
the standard points. These are the
melting point of ice and the boiling
point of water. In the centigrade or
Celsius, thermometer, and in the Reau-
muir thermometer, now rarely used, the
former Of these Is reckoned as zero, or
0 degree; but in the Fahrenheit ther-
mometer, most commonly used for or
binary temperature, it is marked thir-
ty-two degrees, so that the Fahrenheit
zero is thirty-two Fahrenheit de-
grees below the centigrade and Reau-
muir zero" But degrees differ in
measurement, being dependent npou
the number into which the space be-
tween the melting point of ice and the
boiling point of water, as indicated by
the thermometric body in the Their
mometer tube, is divided. In the cent?
grade thermometer this is divided into
one hundred degrees, in theReaumur
into eighty degrees, and in the Fahren-
heit one hundred and eighty, so that
the boiling point, which is called one
thousand degrees, on the centigrade,
reads two hundred and twelve degrees
on the Fahrenheit scale, The term
Zero" therefore, is a very indefinite
one, but absolute zero" is very def
mite one, for it means the entire alb
sence of heat, or the absolute impossi-
bility of obtaining mechanical action
by cooling Measured in terms of eth
err the centigrade scale or the Fahren-
heit, it has a mathematical expression
which is capable of being conceived.
Possibly the following, from the Amer
lean inventor, may give some idea Of
it: DR.. James Dewar recently deliv-
cred his first lecture of series of dis
courses at the Royal Institute, London.
His subject was, New Low Temporal
ture Phenomena" Sir James name
has been constantly before the public
in connection with liquid air Demon
STATIONS, and few scientists have ac-
complished so many new results in it's
use. But Sir James has been able to
attain far lower tempera lures than
that of liquid or even solid air. By its
means he has succeeded in liquefying
every known gas, with the single ex-
ception of hellium, and has reached a
temperature of minus two hundred and
fifty-three degrees centigrade Chat is,
two hundred and fifty-three degrees
below the centigrade Zero which is
the melting point Of iee) with liquid
hydrogen. When this is attained there
is little difficulty in obtaining frozen
hydrogen for a short period; as when
the liquid hydrogen evaporates 1t alb
stracts heat from the portion remain
ing, and so temporarily freezes it. In
this fashion temperature of minus
two hundred and sixty-five degrees
centigrade has been reached. There
would be no particular significance in
this or any other figure if we thought
that there was no limit to the degree to
which bodies can be cooled. But we
shall shortly see that there is a limit,
and that Sir James has very nearly
reached it.
If heat be form of energy, or a
mode of motion, and cold be simply the
relative absence of heat, it is plain
that bodies cannot be cooled Indefinite
ly, since the amount of heat energy
within them must be finite. There
must be, then, an absolute zero of tenn
perature, which bodies will have
reached when all the heat has been
taken out of them. This follows inev-
itabiy from the modern conception of
heat as a "mode of notion" The. de-
ternMation OF the degree to whicll a
body must be cooled so as to lie abso-
luteIy could would appear important.