The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1889-11-10
THE AIR WE BREATHE
A Synopsis Of DR.. Talmage'S Re
cent Lecture.
THE ATMOSPHERIC PRESSURE.
burg Hemispheres-The Mercury shower
b. The Fountain In VacuO.


for the present academic year. A decidedly
interesting and Instructive lecture, on the
subject, 1.-THE Air We Breathe" was de
livered by DIR. j. Z. Talmage.
The speaker commenced his remarks by
giving general definition of the term ''at-
mosphere," and calling attention to the
manner in which the presence of the air
may be recognized. Nature must be ques-
toned by experiments, and the phenomena
produced as result of such questioning
must be taken as her answers. By such
an interrogative process, we may not only
prove that there is an invisible fluid en-
veloDing US, but also that it has character
isAcs for which we, in the natural
course of events, are not likely to
give it credit. To prove that the
atmosphere exer5s a well-defEel pressI re,
the lecturer filled an ordinary tumbler tn
water, placed a sheet of paper over it, i'll
verified the tumbler, and the upward pres
sure of the air held the water in the tum-
bier against the force of gravity. The eX-
pertinent was modified by filling with
water bottle with netting tied over the
mouth, covering it with paper, inverting
the bottle and removing the paper, when
the water still remained close prisoner
being held by the airs pressure.
The pressure of the atmosphere is taken
advantage of in many ways, common
utensil, based in its action upon his force,
being the pipette. Upon drawing water
into this small pipe and placing the fLg,r
over the upper end, the water may be held
il the pipette or allowed to escape as the
finger is held upon the pipe or removed.
The syphon, used in drawing liquids from
vessels under certain conditions, is based
upon this principle A syphOn fountain,
n ha a m nj in
termittent spring, was exhibited and its
action explained.
The magnificent air pump belonging to
the college was used in the performance of
varioHs experiments to prove more fully
the pressure of the atmosphere. The first
of these consisted in placing a cylinder of
glass, one end open and the other closed by
a piece of animal membrane, which was
tied over it, on the plate of the air pump,
and exhausUug the air. Immediately the
pr95sure of the air manifested itself by
bfrsting the membrane with loud report
The pressure of the atmosphere being uni
firm in all directions it does not manifest
ihself upon any surface until the air has
been removed from one side of the object.
This was proven by a member of the
audience placing his hand over the open
end of the receiver, where the membrane
had been, when, upon the air being re
moved from under the hand, it required the
sure, at the sea level, has been found to be
fifteen pounds to the square inch of sur
face, the pressure becoming less with in
crease of altitude. The barometer, an in
strument which was fully explained by the
lecturer, measures this pressure and shows
its changes.
Tho Magdeberg hemispheres, consisting
of two hollow hemisphercs five inches in
diameter, fitted together, werene shown.
The air having been exhausted from the
sphere thus formed and handles attached
to it, it required the combined strength of
eight men to pull them apart, although
held together by nothing but the pressure
of the air The weight litter, consisting
of a cylinder in which a piston is
placed and from which the air
may be exhausted was next shown
A weight of thirty pounds having been at
tached to the lower part of the piston, and
the air exhausted from that part of the
cylinder above it, the upward pressure Of
the atmosphere on the pistNn was sufficient
to raise the weight a considerable distance
from the floor.
Repeating the statement made by the
great Aristotle, we may say mature abhors
a vacuum and she adopts all possible
means by which such may be filled. A
cylinder of glass, closed at one end, was
attached to the pump and the air ex-
hsASted-. The vacuum was preserved by
cl9sfng the open end, through which
SMALL tube had been previously inserted
into the cylinder. The end of this cylin err
was placed in a vessel of water and the
tube opened, when the water rushed with
great force into the large cylinder pro-
ducing the beautiful fountain in vacuo''
It is characteristic of the at
mosphere that it has a tendency to
I'LL to its greatest capacity any
vessel in which it may be held. If by any
means the air be exhausted from around
such a vessel, the atmosphere contained
githin it will make most strenuous efforts
to escape, in order to fill the vacuum around
it. 4 small glass vessel, Theoretically
sealed, was placed beneath the receiver of
the air pump, vacuum being produced in
the receiver. Immediately the air i'm
prisened in the flask exerted such an out
ward pressure as to shatter the vessel into
minute fragments
Atmosphere is necessary to our life, and
il taken from US for a very brief space of
time, death results. To prove this, the
lecturer made sacrifice of a harmless,
unnecessary mousse placing the little
animal beneath the receiver of the pump,
and eXhaustinG the air. The first symp
toms of approaching dissolution were mani
tested by the swelling of the mouses body,
caused by the efforts of the air imprisoned
within the body, TO escape. In a very
few minuteJ the mouse sweetly and
peacefully gave up the ghost" deatA be-
ing, to all appearances, perfectly painless.
Perhaps the most striking experiment of
the evening was the Mercury Shower"
A wooden funnel, with the passage
stopped by a plug of hard oak,
about two inches in length, was
fllskAwith mercury, or quicksilver, the
lowe1Spart of the funnel being placed in a
small glass vessel. This apparatus was
placed in such position upon the plate of
the pump, that the air could be exhausted
from beneath the funnel, although still ex-
erting pressure upon the surface of the
mercury. AS the exhaustion was pro
ceeded with fine stream Of mercury was
seen trucking down into the glass vessel
below the funr el, having been forced by
the pressure of the atmosphere entirely
through plug of solid oak, a distance of
about two inches.
1t has been observed that gases exert a
certain degree of tension under
all conditions This tension was
shown by al experiment OF an
teen partially filled with water and
a balloon inserted, sheet of rubber being
firmly tied over the mouth of the vessel.
BY pressing downward upon this rubber
the tension of the air on the inside of the
vessel was augmented, the increased ten
sion of this atmosphere forced water into
tlfEballoon and it sank in the liquid Upon
the pressure being removed the balloon
arose.
The lecturer spoke upon the adaptability
of the atno sp lere TO the purpose for which
it was Gre aCed by an allwise power, and
closed by inviting attention 20 the study of
those things with which we come in con
tact every day, for an intimate knowledge
Of these constitutes true learning.