The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1894-01-10
ROLLING POINTS.
These Are iaaumeFsbis ana EarIa a ga
Iiaus htudH,

These Are ianameFabis ana Eora a Ga.
risus stnhBt
IL Ii interesting to note that the tenn
perature at which "a liquid boils 10 the
same as that at which it's Vapor is con
densed, precisely as the temperature al
| which water freezes is tho same iis that
al which leo meits.
| 10 may heeIn superiiuous a. observe
that there arc more boiling points than
the boiling point OF water. IT il were
pot so, all bodies would be in tho solid,
| liquid or gaaeous state together, and life
| would les impossible. IL is partly by
| giving every substance its own boiling
| point. on rather it's own set of boiling
| points for the fixed temperature, even
| for the same substance, In IL fallaey-
that nature has rendered our physical
| environment suitable % our needs.
What il generally understood 10y the
boiling point of water In temperature
OF sle degrees on the Fahrenheit Their
mometric scale. but Alpine climbers
know we'll that, ON IA high mountain,
water boiis at "a very much lower tenn
perature- ON tho summit of Mont Blanc
no ls4 degrees. The reason IL that, at
these attitudes, the pressure OF the at
mosphere Is very much reduced since
the density of the air decreases with the
distance above the earth's surface, and
the water expands at correspondingly
lower temperature, passing more read
lily into the vaporous condition. in which
the volume OF IA given mass of any sub
stance As always far greater than that
OF the same mass when liquid. The
boil sxxs Is l..
seen TO depend not only on temperature,
but also on pressure, and the boiling
point of water at 212 degrees CORE
spends to what is called "a pressure of
one atmosphere, approximately 10
pounds to the square inch, or the pres
sure capable of supporting the column
OF mercury in mercurial barometer
at n height of 900 inches. This is
the average pressure of the atmosphere
at the sea level, and if it is reduced the
boiling point is lowered, while if it is
increased the boiling point is raised.
n very curious result is arrived at
If we place a vessel of water in the re-
ceiver of an airpump and reduce the
pressure to .006 of an atmosphere, for
then the water boils at 32 degrees-that
is, at its freezing point under ordinary
pressure. Since it is now possible to
produce an almost perfect vacuum,
water may be boiled at still lower tenn
peratures.
All liquids do not boil at the same
temperature. Thus, while water under
a pressure of one atmosphere boils at
readily into the state of vapor, boils
at 1913 degrees and ether at 93.8 de-
grees, which is below the normal tenn
perature of the body.
Since increase of pressure retards the
of liquid. it of course
facilitates the liquefaction of a gas by
assisting the process of contraction.
Consequently many gases are capable
of being Equefed by pressure alone,
though only when they are below what
is called their critical temperature |
different for every different gas, above
which cold as well as pressure becomes
necessary. Oxygen, hydrogen and nitro |
gen are the most remarkable examples |
Of gases having low critical tempera- |
lures, and it is only recently that their |
has been accomplished at |
all. They We're long thought to be |
permanent gases" but it is now
Known that all gases are hquefable.
The boiling points of oxygen and nj
rogen are respectively 1858 degrees
md 356 degrees F. below the freez-
ng point of water, and therefore
hese are the highest temperatures at
which they can exist as liquids. To
,roduce these extremely low tempera-
ures it is necessary to employ great
PRESSURE along with freezing mixtures.
The most remarkable liquefactionw which
Las yet been accomplished is that of
ir. 1t was supposed that, the oxygen
nd nitrogen having different boiling
'oints, they would liquefy separately.
his is not the case; the mixture lique-
les as air and presents the appearance
f water, but on being again evaporated
he nitrogen evaporates first and the OK
gen afterward. This is puzzle in
hysics which Will doubtless he ex-
lained ere long GOOD Words.
n.