The Highland weekly news. [volume] (Hillsborough [Hillsboro], Highland County, Ohio) 1853-1886, 1880-12-30
Wonders of Temperature.

Every one knows there is no such separ-
ate existence as cold" Cold is only an alb
sence of heat; hence, when we require great
cold, we must use some body which is de-
manding large quantities Of heat. Every
solid, to become a liquid, absOrbs a large
amount of heat; this heat (calIed latent
heat is so pre-Occupied in keeping the body
in liquid state that it can do nothing else,
and refuses to have any effect on a ther-
mometer placed in it. Just so with steam.
Although the temperature Of the steam as
it issues from the spout Of the kettle is
just the same as that of the water, yet we
know that, weight for weight, the steam
contains more than five times the heat
which is in the water. If then, we re-
4uiTe for any purpose low temperature
we must force some solid to become a fluid
or some flUid to become a vapOr.
The cOnfectiOneTs apply this principle
in making ices" The creamy preparation,
placed in a metallic vessel, is immersed in
broken ice mixed with salt. Now it hap
pens that, for some unknown reason, salt
and ice so act upon each other as to cause
the ice to liquify, but this it is unable to do
unless it has heat: this it abstracts from
the cream, which consequently freezes.
i NO Dal u OL DUuuuGlL lGC A4LAGu W I'LL OllJ
of common salt can reduce the temperature
36 deg. below the freezing point Of water;
or If, instead Of the salt, three parts Of
Crystallized chloride of lime be used, so low
a temperature is produced that mercury
Will freeze. Yet low as we can get the
temperature by these freezing" mixtures,
it is nothing to the wonderful degree of in
tense cold which the vapOrizatiOn Of some
liquids can produce.
There is every reason to believe that
gases are in reality liquids in vapOr. Many
of them, by being forced into a wrought
iron receiver, by means of a forcing pump,
can be Hquefied. Of course, when the IL
quid is taken out of the receiver, and re-
heved of the enormous pressure under
which it existed, it Immediately endeavOrs
to return to its gaseous state. 1t is II
tremendous hurry to do this, and, seeing it
is unable to become a vapOr without it re-
ceiYes a great increase of heat, 1t commands
all the surrounding bodies to deliver up
their heat in the most peremptOry manner.
Laughing-gas, or nitrous oxide, so condensed
under a pressure of 45O lbs. on every square
inch Of the receiver which held the gas,
and then liberated, can produce a tempeTa-
ture by its rapid evaporation nearly 200
deg. below the freezing-pOint Of water;
and, by causing this process to 60 on under
the exhausted receiver of an air-pump, the
greatest cold has been prOdUced-nearly 300
deg. below the temperature Of ice.
But perhaps a more remarkable fact is
this: that it is possible to cause extremeT
of temperature to exist in the closest jUxta
position. If some Of the Hquefed gas above
mentioned be placed in a red-bOt platinum
rucible, and then little water dropped on
t, the water will turn into ice. Imagine
reezing in a Ted.hOt cTUcible! nay, even
mercury can be made to take the solid state
nder similar circumstances, and frozen
mercury is so cold that when held in the
land it Will blister it as though it had been
piece of red-hot iron. The reason that
the liqUefed gas was not instantly dissi-
pated by the heat Is the same as that which
causes a drop Of water to dance about on
an almost Ted-hOt plate of metal: the drop
does not really touch the plate, but is sur
rounded by an atmosphere Of yapOr, upon
a thin layer Of which itTests. An ingen-
iOus application Of this real Y wonderful fact
has been long in use in glass-WOrks. The
mode of making British plate-glass is to
blow cylinder Of glass, then cut it open
and spread it out. To make the cylinder
even and symmetrical, the glass is blown in
q wooden mould, the sides of which are
wetted with water; the red-hOt glass con-
verts this into steam, which keeps the glass
from burning the wood, and also from
touching the water which would at once
spoil it, rendering it brittle.
If possible, more wonderful, and indeed,
all but incredible, is the finding of ice over
which lava-bed has been poured centuries
ago. The ice was first covered with layer
Of cinders, which are bad conductors of
heat, then came the molten lava; and the
power of the ashes proved
sufficient to prevent the heat of the lava
from melting the ice.