The Yellowstone journal. [volume] (Miles City, Mont.) 1893-1901, 1893-12-23
BOILING POINTS.
are innumerable ;,Dd Form u Gu
rious study.

V wv t'N
rious study.
II lntcrestinr II Iote that % tenn
e., ture at whie Il liquid boils Is tn
l,me as that at wnich its vapor Is con
iensed, precisely as the temperature Il:
which water freezes is the same rs that
at which ice melts.
1t may seem superf1uous to observe
that there are more boiling points than
the boiling point of water. 1t 1t were
not so. all bodies would be in the sG!!t
LIQUID or gaseous state together, ana l.le
would be impossible. 1t is nartly ny
giving every substance its hnllln.
point. or rather its own set OF boiling
points-for the fixed temperature. even
for the same substance, Is a fallacy---
that nature has rendered Il physical
environment suitable to our needs.
What is generally understood by the
boiling point of water is a temperature
of 2ta degrees on the Fahrenheit ther-
mometric scale. but Alpine climbers
know well that. on a high mountain.
water boils at a very much lower TEN
perature-ou the summit OF Mont Blanc
at Isl degrees. The ieason is that. at
these attitudes, the prassure of the at
mosphere Is very much reduced, since
the density Of the air decreases with the
distance above the elrth's surface. and
the water expands a a CORRESPONDENCE
lower temperature. passing more read
lily into the vaporous condition. III which
the volume Of IA given mass Oh amy sub
stance is always ar greater than that
of the same mss when liquid. The
boiling point o. liquid is, therefore.
seen to depend not only on temperature.
hut also on pressure. and the boiling
point of water at 2l2 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 d mercurial barometer
at 4 height of 80 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.
A very curious result is arrived at
if we place a vessel OF water III the re
ceiyer Of an airpump and reduce the
pressure to .0G6 of an atmosphere, for
then the water hollis at 30 degrees-thGt
is. at its freeing point under ordinary
pressure. Since il l. now possible t.
produce an almost perfect Vacuum.
water may be Goii-a - std. i"r:ri~aa
peratarEs.
All liquids t. 1T TIL = IT, s:-e.
temperature. TIN ahiieA.t' ru.-'.
a pressure Il Il aH-ars 1..e i"sEs'&'
a12 degrees. alaaho9. "Aiea i=t4E.
readily into the ST 81 raHar, itt.-
at I1a.3 degrees and ctll'r at 20. Il
grees, which L. below the l]osIaai + IN
perature OF the bgay.
Since increase Of pressure rct!rIS ta
vaperizatien III Il liaaia. IT 81 c=E+
facilitates the !~iquefaetion Il ii { i +,
assisting tine process 81 contraction
Consequently many gases ar eap#.bis
of being lIquefed ly pressure a!er"
though only when they are below WIFI
Is called their critical Temperature
different for every different gas. ayov,
which cold Is we'll as pressure become
necessary. Oxygen, hydrogen and nitro
gen are the most remarkable example
OF gases having low critical tenrera
lures. and it is only recently that tle1i
li~4Hefacti8H has been accomplished n
all. They were long thought to ID
permanent gases. but it Is nov
known that all gases are liquetiable.
The boiling points of oxygen and nj
trogen are respectively 3.5.s degree
and $50 degrees L. below the treez
ing point OF water, and therefor
these are the highest temperatures a
which they can exist as liquids. L
produce these extremely low tempera
lures ii is Necessary TO employ grea
pressure along with freezing mixtures
The most remarkable liquefaction whiV
has yet been accomplished is that Q
air. 1t was supposed that, the oxyge
and nitrogen having different boilin
points. they would liquefy separately
This is not the case: the mixture lique
ies as air and presents the appearance
of water, but on being again evaporate
the nitrogen evaporates first and the o.
ygen afterward. This is a puzzle l
physics WHICH will doubtless be e,
planned ere long.-Good Words.