Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1884-01-19
TIE INVENTION OF ray BAROMETER.

NJ. illumination, French scientist. in.
forms US that in 1910 the Grand Duke of
Tuscany, having ordered the construction of
fountains upon the terrace of the palace. it
was found impossible to make the water rise
more than thirty-two feet. The Duke wrots
to GsliIeo in rrfe-71ce - this strange refusal
of the water =. eoeI he pumps. Torricelh,
the pupil ana friend of Calico gave the true
explanation of the fact, All proved, a. we
shall see, that the column Of water Of tdicty
two feet was in equilibrium with the weight
of the atmosphere. II was, then, the refusal
of the water to rise more than thirty two
feet, in obedience 20 the pumps. which re-
yesled to Torricsli the fact (, at chs Amos
phere has weight, AMI that tbH whole weight
was balanced by column OF water thirty
two feet in hight. Before GslilsO's day the
ascension Of water in the suction-pump was
ascribed 10 the fact of nature sbhorring q
vacuum, but it Is, in reality, merely an effect
of atmospheric pressure. Take q tube, at
the lower extremity Of which is piston, and
place this lower end in water. Ii the piston
Is drawn up. vacuum Is created below. and
the atmospheric pressure, acting upon the
surface Of the LIQUID external to the pump,
makes it rise in the tube and follow the
movement Of the piston. Herein lies the
principal Of the suc,ion-pump. For water to
reach the body Of the pump, tne suction-ya.ys
must be less than 81 or SS feet above
the level of tbs water in the well. otherwise
the water would cease to rise st certain
uOint in the tube, and the motion of the piston
would be unable TO raise i any further Ia
addition, 10 insure railing AZ each ascent OF
the piston . volume Of water equsl to the
volume Of the body Of the pump, the spout
must be placed at less hight than 81 t-et
above the reservoir. In reference to this eia-
walton of the water only to a certain hight,
Torriceli, throwing aside, like his master, oil
ides OF hidden cause, showed that the
pressure of the air Compeis She water to
mount up into the pipe from which the air j.
Withdrawn, until Cna weight OF water
raised into the pipe Is equivalent so that OF
the air which presses upon al equal section OF
reservoir from which the water is being
r0issd By the aid If this principle be WIS
led to invent the barometer. 10 exercise
equal pressure the liquid columns must Be Of
1 nights inversely proportional 60 their density,
| Thus, liquid twice SIS heavy Ga water would,
with a column Of is feet be in equilibrium
with the atmosphere and quicksilve-, which
Is nearly thi- en- aud half times IS heavy
as water, would be In equilibrium il the hight
| OF the column was diminished IN this proper.
tjol-thst Is, to about % inches Tais con-
c!usiou is easily verified. Take glsss tube
three feet in length and open only st Que sud,
fill it with quicksilver, and then placing the
finger on the open end put Jhat sLi
Of the tube into s basin filed with the same
/ liquid: remove The finger and the quicksilver
in the tube will descend several inches aud
/ then stop The equilibrium IS established,
aud the liquid column, which remains sus-
pended in the tube, is q true balance, for the
weight of the column Of mercucy is exactly il
equilibrium with the atmospheric pressure.
Tor cell gave to this Tube If quicksilver, thus
placed vertically in q basin OF quicksilver, the
name Of barometer. Its invention by Tori
cell dates from 1913. The surface Of the
earth Is pressed upon as if it was covered with
body OF water 50 or So feet deep,
and we Who live upon the bed of this ocean
Of air undergo the same pressure. The
pressure Of the atmosphere on "a square inch
Is equivalent 90 the weight Of a column Of
quicGs liver, with q volume Of % ~ cable
inches, OF about Ettaeu pounds. II is assy
and Interesting TO draw from this the coucu-
sion that, as the euperhcieS Of on average
human body Is sixteen square feet, We may
each Of Us be said Co be subject 10 a pressure
Of about fifteen tons. That we are not
crushed by this enormous pressure is because
it does not all press vertically down upon us.
As the air surrounds Us on all sides, the pres
sure is transmitted over our body in all di-
recti9us, and, in consequence, becomes neu-
UIalZed