Rutland weekly herald. [volume] (Rutland, Vt.) 1859-1877, 1873-09-11

A PAPER READ BEFORE THE AMERICAN
ASSOCIATION FOR THE ADVANCEMENT
OF SCIENCE, AT PORTLAND, MAINE,
AUG. 25, 1873, BY GEO. J. wARDwELL
OF RUTLAND, VT -...... ..-....s.. ..
While the subject matter of this paper
relates particularly to the cohesion OF
LIQUIDS, and an apparatus for determining
the same. | shall have occasion TO al
lude to this property of matter IN con-
nectiOn with metals, as there are certain
causes that produce the same effect, when
allowed to act upon liquids or metals,
and one or more peculiar characteristics
which affects the one and not the other
1t is due to this property of cohesion,
that all matter hold their forms, ana as
substances do not possess it in equal
measures the amount which any one
substance may be known to have, fur
nisbes no data that will enable us to
Judge correctly what amount Is possess
ed by any other therefore, 1t Us neces-
sary that each particular kind of matter
should be subjected to special tests AS
respects the metals, and in fact, nearly
all solids, this has already been done,
and the quantity which each kind OF
matter may have, is expressed by the
number of pounds required to tear asun-
der or crush a piece of the material,
whose cross section measures one square
inch.
A knowledge of the cohesion OF the
different solids enables the architect, en-
gineer and mechanic, to select the most
suitable material for their structures,
where strength and stability are re-
quired. -
A rod of iron, whose cross section
measures one square inch, will resist a
strain or force of 10000 pounds, or sus-
tain rod of iron, of this size, 81 miles
in length.
If it were possible to suspend such
rod, and then apply heat to its upper
end, the weight or length which it coulC
support would be less, and thus the
weight and length which it could sustain
would be less, as more heat was applied
and it would continue to do so, as thu
temperature increased, until the melting
point of the metal was reached, whel
the cohesion of the iron would be DIES
troyed.
Now we will attempt the making o
an experiment, somewhat analogous e
me one JuSL ueSCJl UGus Win AlJuAN ~
will use hollow cylinder, 80 feet O
more in length, provided with clos
and nicely-ftted piston, the face o
which, having an area equal to on
square inch, and place them in vertica
position with the lower face of the pts
ion, immersed in some liquid-water TO
instance; then, by raising the piston
the water will follow, and it will con
tinue to do so until the weight of tn
liquid column equals the cohesiy
strength of the liquid, at which point, ]
the piston is raised higher, the fluid col
umn win be broken. The weight of tn
column, thus raised, will indicate tn
cohesive strength of that particula
liquid.
If the experiment should be repeated
with the temperature of the liquid raised
the weight and length of the colum
would be less at the breaking point, an
they would continue to be less at highe
temperatures, until the boiling point wa
reached, when the cohesion of the liqui
would be destroyed.
In the experiment with the iron roc
the cohesion of the metal was what SUI
portedthe weight, up to its breaking poll
but such is not the case in regard to til
hquld, as the cohesion of the fluid serve
only TO remove the atmospheric pressul
at its surface, and as the cohesion b