Staunton spectator, and general advertiser. [volume] (Staunton, Va.) 183?-1849, 1846-01-01


raises the wate', we. may by calculation deter
mine the diameter of that tube. - .ks
18th. Different liquids, are raised to differen,
heights in the same capillary tube. Thus tube
which will raise water % inches, will raise alco-
hol bot inches, and will not raise mercury a,
all, indeed glass capillary tube will depress in
stead of raising mercury. This difference in
height TO which different liquids raised, is not
owing entirely TO difference in weight in those
liquids, is evident from The case already stated
of waterand alcohol the latter being the light
er liquid of the two is nevertheless not raised so
high as water, the heavier one.
5,h. Capillary tubes. of different materials,
will not raise the same liquid to the same height,
although they be of the same size. capillary
tube of Spermaceti for example will not raise
water as high as one of glass Of the same size.
9th. This attraction seems to be exerted BY the
surface of the tube only, or at most, by the sur
face and a very small portion of the matter OF
the tui.c1iying next the surface; as water will
rise as high in the thinnest glass tube which we
can make as it will in the ihickest, the size OF
the bore of the two tubes being the same.
7th. The force with which liquids are absorb
ed by capillary tubes is very great, as exempli-
fled in the prodigious force with which seasoned
timber swells when wet:--ihe swelling OF the
timber being attributable in this case TO the abb
sorpiion Of the water by the tubes or pores of
wood and their consequent swelling out, when
before, whilst empty, they are flattened.
Such is brief statement of the effects COM
monty attributed 10 capillary attraction. TO
these we must add several others, evidently
owing to the same cause and which will re-
quire modification in the definition of the term
in order that they may be embraced under it.,
viz:
lst. Liquids rise between parallel plates placed
near to each other In manner similar to that in
which they rise in small tubes; but as two plates
a -
but half the amount Of surface TO act upon the
liquid contained between them, which a tube,
the diameter of which is The same as the distance
between those plates will 10 the liquid contained
in it, these plates will raise the liquid but half as
high the tube.
20. All small pores or openings, whether they
be tubes or not, such for instance as the inter
stices between the f6res Of twisted cotton, and
the openings between par,icies Of the soil are
capable OF absorbing liquids by means of this
species of attraction.
3rd. If you touch plate OF glass TO the sur
face of water, il will be found TO adhere TO that
surface with very considerable force, and when
from it, it will Gerry up portion Of
She water with it, or in other words will. be wet
by the contact.
4th. Gases are operated on in the same way
by the pores or capillary tubes and surfaces both
OF solids and liquids, as liquids are by those of
solid bodies. The force with which -ses are
thus attracted is often very great; sometimes as
great al least as $4,000 pounds to the square
inch.
From these facts, it is evident :.,at the common
defnltion of capillary attraction is much too lin
tied, hatit Is III fact attraction of heieropene-
Gus surfaces, i. e. surfaces Of different kinds;
and hence some laie writers on chemistry have
given IL The name of attraction Of adhesion, con-
eidoring wii.ts Formerly -o"l!.,d capillary
traction, nothing more than manifestation of
aC
stances.
We are now prepared to enter intellgently up
on the explanation of The effect produced by
stream of hydrogen when projected upon piece
OF spongy platinum. Spongy platinum is sub
stance at once remarkable for it's extreme porosi-
~ and for the smallness of its pores, aud of
course, for its admirable adaptation 10 exert a
great amount of attraction of adhesion. When
a recently prepared piece of this substance is
placed IN contact with atmospheric air, it at once
absorbs large quantity of that air Containing
oxygen of course) into its pores: and by con-
densing ii, brings lis particles much nearer ioge-
ther than they are in ordinary circumstances. Of
the extent 10 which this condensation, and of
consequence, the approximation OF the particles
OF the gas Is carried, you can form some idea
from the fact, that cubic inch Of spongy pla-
nun is capable of absorbing 500 cubic inches of
pure oxygen, and thus bringing the particles of
the oxygen more than 500 times nearer to each
other, than they exist in ordinary circumstances.
The essential difference between gas and Ii
qnld consists III the relative approximation of
their PARTICLES. Hence when we wish 10 make
gas assume liquid form, we drive the particles
nearer together, by means Of great pressure, or
we remove the heat of The body, the repuIsive
force OF which tends TO drive its particles asun-
der. and thus enable the attraction of cohesion 10
draw the particles together. Now, in the case
before us, The spongy platinum produces simi-
lar effect upon the particles of oxygen by means
OF its attraction of adhesion, force in this case
equal 10 upwards Of 1000 pounds, or every
square inch, as those familiar with the laws which
govern the condensation of the gases can easily
determine by calculation. In the pores of the
platinum, this oxygen or atmospheric air, must
exist In condition very similar TO that Of Ii
quid, If not in liquid form itself, the form best
adapted to the operation of chemical affinity (see
LIST sec. 2nd law Of affinity when stream of
hydrogen Is projected upon piece of sponoy
platinum In such circumstances, it also is alb
sorbed, and condensed in the same way, and per-
maps liqufed, or at least brought into condition
not very unlike that Of liquid, and thus the
cause which prevented the operation of the Atm
ry OF these two elements III their gaseous form
being removed, chemical combination at once
ensnes, accompanied with the developement of
sufficient heat 10 render the platinum wLi,e hot
(see Lee. 2, Law 10Th Of affinity.
On thus explanation allow me to make the tw %
following remarks, viz:
LIST. The effect here produced is owing entire
Iy to the spongy character, or porosity of The
srongy platinum. If we project stream Of n.y.
drogen upon piece Of solid metallic platinum,
no eject whatever is produced.
I'd. Although the immediate effect is purely
mechanical, consisting in the condensation, and
possibly, the Iiquifaciion of the Two gases, yet
the ultimate effect is chemical one, consisting
IN the combination Of the two gases, and the pro-
duciion OF a new compound Tin this case, water)
evidently different in It's properties from either Of
lis elements.
NJ OIL will nnyy nndnrstanL liz, r.nxa IL No.. l..