The Sumter banner. [volume] (Sumterville, S.C.) 1846-1855, 1855-02-14

de'lterlouS to animal life, and would
eventually produce serious crnsequen
ces. Although it was well ascertain.
cd that this gas which is thrown from
Tie lungs Mt each respiration is much
heavier than common mir, yet the law
which governs its elasticity under VA.
rlous pressurcs was not SO we'll dcfin.
ed, while present, | therefore closely
observed the appearance of the light
which by Il peculiar halo around its
top always indicates the presence of
this Gas, when in sufficient quantity
to injnre animal life.
N" seri"us difficulty was cncoun.
tered in removing the sand or in cut
ting away the tree which arrested the
decent Of the Cylinder, and which
proved to be a large Cypress perfect
ly sound.-As soon rs the tree was
cut Away aud the compressed air dis.
charged the Cylinder settled down
about 4 fcct-nnd n frcshet coming
about the same time. operations were
suspended. TIE second Cylinder was
lowered to its place as soon rs the
frcshet subsidized, and by the Pncunat.
Ic process it was driven to depth of
about six feet. At this depth, the
friction countcrbalanccd the power OK.
crted by the vacuum and it therefore
became necessary to remove the intc.
rior column Of sand. Efforts were
made to pump out the water and re.
move the sand, but it was found that
the water could not be reduced by
Pumps more than six feet below the
level on the outside, and the Air Lock
was again used and at the expiration
of the first days work (when about 3
feet ofthc sand hud been removed)
and after the operations were suspend.
ed, the Cylinder was observed to set.
tic several inches. On the succeed.
ing day, the removal of the sand to
the bottom Of the Cylinder was com.
Pletcd, and, with view of observing
the effect, man was stationed at each
valve with directions at given signal
to open it that the compressed air
might be suddenly discharged. The
result was that the Cylinder was driv.
Ell six feet, which exceeded the great.
est effect produced by the exhaust or
vacuum.-ln rcflectillg upon the cause
which produced this effect, discov.
cred that it was the ny ydrosta.ic action
of the water which secured out the
material beneath the bottom OF the
cylinder, which partially relieved the
friction and caused it to descend by
its own gravity. In addition to this,
after the air in the cylinder had been
compressed until it was equal to the
force cxerted by the water in the out.
side, the interior pressure could not
bc increased, and the air which was
pumped in by the continued action
of the pumps. escaped under the bot
tom OF the cylinder and become incor.
poratcd with the sand.-somc Of it
rising to the surface. When the com.
pressed air was discharged the cquili.
bri"nl was destroyed and the air in
rising to the surface on the outside
and around the cylinder, still farther
relieved its friction. ('rhs, the second
cylinder. also encountered in its dc
scent an oak tree, about 4 feet in di.
amctcr, but, unlike the first, i. was so
soft that the weight Of the cylinder
easily cut through it. On exposure to
the atmosphere it became hard, and
IN every respect was perfect Ii -nitc.-
This is mentioned to show the differ.
cnt results pr"ducrd on the two quail.
ties of timber by the action ol tho wa
ter, rs they were in the same stratum.
and evidently deposited at and belong
to the same period Of timc.)
1t was apparent that the hydros,atic
action of the water was more effective
than the pneumatic process. and it was
subsequently used principally in dri.
wing the remaining cylinders, and
towards tue close Of the work, the
pneumatic process was entirely aban
d"ned and the hydrostatic principle
alone used.
This | consider discovery of the
operation ofa known principle giving
greater power than that by the pneu.
matte process, and applicable to the
sinking of hollow piles.
AS before stated, the power of the
pneumatic process is limited by the
relative proportions Of the vacuum
chamber and that portion Of the pile
above the surface of the water, aud
the perfection ofthe vacuum. In prac
tlce, the exhaust cannot be applied
unless the top of the pile is at least
six feet above the surface of the water,
because the pile might be driven below
the water line, when another section
cannot be added. The power is uni
form and cannot, under any circum.
stances, exceed II 3 4 lbs. per square
inch, and, in practice, rarely exceeds
8 lhs per square inch, while the friction
with q column of six feet Of sand on
the interior Of the cylinder is equal
to this power. The deeper the pile is
driven the greater is the friction, while
the power remains uniform.
With tho use Of the hydrostatic
principle, the power increases with
tho Distance from tho ,nrCaoo oc ,Lo