New-York tribune. [volume] (New-York [N.Y.]) 1841-1842, 1841-12-29

shorter. For csnvenience's sake he used quick
silver in his experiment, which IS thirteen or iour
teen times as heavy as water, and therefore ought
TO give column of only about thirty inchcs- 10
submit this 10 the test, he took ass tube open at
one end and closed at the other; this ne Tiled With
quicksilver and placed the open end II 4 vessel OF
tha same liquid Now said ne. il the pressure OF
the ar support column OF water IL ought 10 sup
port column of quicksilver OF the same weight
aud this ne feund TO be precisely the case.
Now YOU would suppose that such demonstra-
ton as this OF fact important and interesting
would SATISFY every one. But YOU must remember
the tramncls Of preiudice-the desperate ienacity
with which men cling 10 loag received opinions
This demonstration did not convince every one; on
the other hand il convinced very few. Some lew
assented IL il, while the great majority thought
that 1t had not been sufficiently proved. Sope one
was needed 20 apply 10 the solution the tinal test
TO apply what BAcoS calls the erpsTfmsHtun CRIT
els. This one was soon found in PAscHAL, WIKI
whose name and works YOU are all doubles, ac
quainted. Although he firmly believed that the
explanation OF ToRlcELLI was the right one ne
saw that an experiment was still wanting which
should put /; past all deabi, and this experiment
fsaa cruces. or experiment, winch, when there were
Two or more methods OF explica;ioa apparently OF
equal validity, should poin; gu; deci,ivey the true
and the false, PAscHAL prepared "a supply. he
reasoned hus:-lf the weight of the air De- the
principle which sustsins the mercury in the lube,
il carry the tube UP in TIE atmosphere 10 great
hight as porten OF the sustaining all Is thus elt
behind the mercury ought 10 fall but II some 9th
~ cause be the one II w!iremain ~ the same
hight. PASCAL accordingly wrote friend
living near mountain in Auvergnc in France de-
scribng the experiment he wished 10 make: and
now said he as have no convenient means for
accomplishing this, pray I'LL glass tube with mer-
curry inihe manner described, take ii ap TO the isp
OF your neiehborng mountain, and see il II do not
fall several inches His friend obeyrd his wishes.
and found the result Just what had been snticipa-
Ted. As ne carried IL toward the top the mercury
continued 20 fall PAsCHAL soon after repeated
the experiment on one OF tina high towers of Paris
that OF Nctre Dame, | beli.re--anG 20 his COM
plete satisfaction. A happier more beautiful
illustration of what BAcoS meant BY the expert
nieHtum craciS can scarcely be found in the whole
range ofPhyscs
The barometer the principle of which have
jhus been describing, is, as YOU all aware, often
called weaiher-glass. 1t i. NOT my purpose at
present to 90 into description OF the barometer;
but may speak briefly OF what the barometer does
really Indicate and what ii does not. And in
word NAY say that it indicates nothing else thaA
the weight of the atmosphere. If taken to an
stler part of the same building-it it BE- taken TO
the top of church tower, the mercury in it will
fall for the weight of the air it measures
is now less than before. If il be kept in
given place, the mercury will stand at different
nights at different times from The operation OF va
rious causes. Upon the barometer. usually con-
structed are engraved At various nights the differ
cnt terms fair, foul, rainy. &c. il the con-
dition OF the atmosp here indicated pre-
diccd by the hight Of the mercury. That this !,
not the case, any one Will be convinced BY consid
ering that a barometer may Indicate fair weather
the bottom, and foul weather the top OF
church steeple, since the hight Of the barometrc
column will be different for the two positions
Whit, then, are the indications OF the barome-
ter to be relied on This is not readily answered,
as mono of its indications are invariably trae. All
that can be said of lis promptings IS that certain
effects will probaJiy follow certain change As
general rule, if the barometer suddenly falls foul
weather may be soon expected and if it suddenly
rises fair weather Will probably follow. These
rules, however, greatly modified by various cir
cumstance-. In summer, if it suddenly falls,
thunder may be expected and ii in winter
frost These only be relied as probable
indications as to the terms upon the barometer,
they are perfectly futile and should not be there.
A second and striking Natural phenomena. Sc
scted for analysis, this evening, is that of Der.
This is rendered celebrated for the extremely
beautiful investigation Of which the discovery
of its theory arose We are indebted to an emf
nenl Natural Philosopher, Dr. WELLS. for this
theory, and he developed it complete il all its
parts and | that You will consider il
most beautiful and satisfactory if | can succeed in
I 10
natural phenomenon is to be examined and a clear
cause assigned TO it, the first duty Of The Inquirer
though unfortunately it is one not always observed,
is 10 obtain clear conception of the thing the
effect itself, which We propose to examine In an
inquiry into the nature and origin of Dew, it i,
necessary first to distinguish it from other things
which may ba supposed to resemble il more or
less. For instance it Is not rain rain falls IN
drops regularly formed in the air before they are
deposited the Eurth's surface Dew does not:
nor is it ever known TO exist in liquid until
it pouches the body oa which it Is deposited. Rain
falls dew collects. Rain Is driven upon the
under side of leaf: dew l. likely 10 be found
there as elsewhere. Nor Is dew the same fog
for fog never exists unless there be dampne-s IN
the alme. phere. while dew is never found unless
the SKY be clear and the air dry. You see then,
what dew is distinguished from other objects.
We mud 1t existing IN objects upon the surface oi
the Earth, clear, Pellucid drop; but in order
clearly to investigate It's character one must open
the Book of Nature und diligently read is pages.
The Ancient- set up lofty theories which they only
though, of supporting the modern philosophy cub.
mts Nature 10 the severest examination and exterts
from her the truth. When any question is proposed
tor investigation, the first and most natural inquiry
Is, whether there be any other similar effects Tor
ii there are, they probably owing the
cause and If this be known in the latter case, OF
course it is in the former also.
Every one must have observed that ii glns-
d-cantrr tlIed with cold .ya.er i'm q anrln d. he