The Bloomfield times. [volume] (New Bloomfield, Pa.) 1867-187?, 1871-12-19
SCIENTIFIC READING.
THE ATMOSPHERE.

NNHE term "atmosphere'' is from two
Il Greek words, which signify a sphere
Of Udpor and the name quite accurately |
describes to us the truth, when we remem-
Der the definition of "vapor" as "matter |
temporarily in an aerial form !" for the at |
mosphere is sphere of various kinds Of
matter in an aerial form, though most Of it |
is not temporarily but permanently so and |
therefore, more accurately comes under the
term of gases. That air and indeed all the
gases are truly matter, is fact which most
of us find it a little difficult always to rea-
lie. Ordinarily the most important of
these gasses do not appeal to our senses
we neither see, hear feel, taste, nor smell
them. Nevertheless, they are as really and
truly matter, though in finest atoms, as earth
or iron and we cannot too much accustom
ourselves to think on them in this light SO
there will be less of mystery in many of
their operations.
We are really at the bottom of a great
ocean of gas or vapor, which surrounds the
earth. How deep this is, has never been
ascertained, but probably not less than
thirty miles. DIR. Buist has said not less
than fifty nor more than five hundred, but
the latter number is greater than almost
anybody else has named. SO elastic, how
ever, is this atmosphere, that the upper
strata grows rarer with the greatest rapidity.
We know that half the weight of the whole
is comprised within three miles of the
bottom. Ascending to about the height cf
Mount Blanc, the pressure is but half as
much as at the surface of the earth. Till
the year 1643, no means had been found to
tell the weight of atmosphere. Then the in
vention of the barometer, by Torriceli,
showed that the whole weight of a column
of air reaching from the surface of the
earth to the top was balanced by column
of mercury ofequal base, reaching about
thirty inches high. 1t varied somewhat at
different times the range being some two
or two and half inches from one extreme
to the other. Weighing column of mer-
curry, therefore, the base of which was an
: inch square, and the height thirty inches,
would give the weight of the average col
found to be fifteen pounds, from which it
was easy to calculate the weight, or pres
sure of the whole atmosphere. And we
are little startled at being told that this
is equal to a globe of lead sixty miles in
diameter, and that every common-sized
man unconsciously bears pressure of some
fourteen tons. This being so, we are GER
tainly prepared to appreciate the advan-
. tages offs proper distribution of the burden
r Common air constitutes nearly the entire
, bulk of atmosphere. To appreciate the
| nature of this we must keep in mind the
{ and chemical union. Shot and sand
S mixed in cup will not unite, but each
| retain the same nature shot and sand still.
S Just so, salt and water mingled wonld re-
i main truly salt and water still. Not so all
substances There are very many which,
! being mixed, instantly unite and produce
another substance very different from
d either. Water and air are the two most
' common substances, and the chemical
knowledge of almost every school-boy
] iNdSIlOo iai ShpuBh w soy uhttO toSh 10 Sohi
posed of two gases-the former oxygen anG
hydrogen the latter oxygen and nitrogen
!" Each of these gases is itself invisible bu
+ bring the first two together and they in
o stantly unite and form water, which, pal
IL pable, visible is different in it's nature from
u either. Here was chemical union. Blu
II bring the last two together, and, having
l. no such affinity for each other, they simpl,
a mix each retains as much as ever its owl
e nature. And it is well for us that it is so
r for if only these two elements united chem
o ically in one proportion, Jas we have TIN
re means to compel them to, though they viii
ii not do it spontaneously, they would pro
duce laughing gas, while in another pro
portion they would give nitric acid-in TIN
4 one case, if we were compelled to breath
le it, turning the world into worse than
10 bedlem of drunkards in the other, instant
le ly destroying us with the most deadly o
E. poison. So we may say our safety depend
or on the continue%Gwant of affinity between
he these two. Let them, so to speak, chang
in their minds and love each other better, AM
lie we are gone. AS it is, we are safe, Will
IN they simply mingle in each others SC
n ciatv