The Black Hills union. [volume] (Rapid City, Pennington County, Dakota [S.D.]) 1889-1904, 1904-01-22
MODERNS COPY FROM
ANCIENT ENGINEERS
Bridge In New York Moved
just as Egyptians Handled
MonoIiths.
WORKING OF SAND JACKS
They Were Used to Settle the Great
Stones of the Pyramids Into Place,
and No Better Device is Yet
Known.

Chicago Chronicle: Few achievements
of the engineers OF modern times have
beer more gigantic or more successful
than the resent movement OF the Lncka-
wanna railroad bridge at Newark, N. j.
1t was found necessary TO remove the
s%truture, a heavy steel affair, some nifty
feet. and officials desired that as little in
terruption of traffic as possible should
take place. The problem is one that has
often been solved, but in this case public
attention has been directed to a special
method. After the draw span had been
lifted from its old position and foated to
its new one on barges. instead of lowering
1t to Its bearing by screws or hydraulic
jacks, 1t was lowered by means of sand
jacks" On the barges were boxes filed
with sand on which the bridge rested and
the same was allowed to run out OF suit
able openings In the boxes and so let the
bridge down.
This Is exactly the method that was
used in Egypt 1000 years ago in placing
the huge itntels OF the temples on the col
umns. The stones were dragged by main
force up inclined planes formed of bags OF
sand to q position over the tops OF the
columns. Then the bags were pierced and
the sand, slowly escaping. let the stone
gently down to its bearings.
Ancients Knew the Art.
It Is probable that a similar method was
used in erecting the obelisks, which we
today find difficult to handle with steam
to aid us. just as the lintels, so the
obelisk was dragged to the top of a heap
OF sand bags until it's base was over, but
far above the foundation. Then as the
sand was gradually removed the base
would be lowered until the obelisk re-
cllned IN Il slanttng position on the sitp
of the slope of sand, with its base rest
ing on the foundation. 1t was, of course,
not yet upright. but by far the most diff
hcult part Of its erection, the raising of
the summit through the lower part Of the
quarter circle 1t must describe. had thus
been overcome, and 1t was then but a
matter of wedging up the upper end little
by little and building up the sand slope
until the final position was reached.
Partly to make the turning on the low
er edge easier, but principally to prevent
Its being cracked off, the sharp angles of
the base were rounded, especially at the
corners. In the obelisll now in Central
park the crabs that seem to surnort II
ful the space made by the cutting WAY,
oil the corners for the reason specified.
Used in Egypt's Tombs.
In some of the tomhs cut in the cliffs
thai hem in the Nile valley. as well as in
those built in the pyramids, sand Jacks
still more closely resembling those used at
Newark can be found. The protection of
the chambers that contained the sar-
cophagt, while leaving the richly deco
rated vestibules and passages of the
tombs accessible, was one OF the most i'm
portant matters in their construction. and
TO do this stone slabs, resem-
Ding the masonry on each side, were
used TO close the narrow halls leading 10
the burial chamber. The slabs were
somewhat wider than the full width Of
the passages and slid in grooves at the
side up into u pocket in the roof.
The tomb was built with the slab in
place In the pocket, leaving the passage
open under it. 1t was supported bv small
square columns of stone G" wood hidden
IN the grooves and resting on sane that
illed the lower ends of the grooves. which
extended down into the floor. Ingenious
~ contrtved channels led from the lotion
OF the grooves to the outer part of the
passage and when the last sarcophagus
nad been placed in the chamber the plugs
tnat closed the channels were taken out
TO let the sand escape. The slab SLOWLY
descended until its lower edge rested in a
slooVe IN the floor of the passage and it
could then never more be raised, for sides
top and bottom were embedded in the ma,
sonry and there was no crack where a
lever could be inserted or a hold of any
KIND be obtained. The slab was usually
oi sucn thickness that 1t gave no indica-
~ VIC ioiioWneSS behind it when
struck and to all appearances the massage
would seem to end in a cul de sac.
Other Engineering Feats.
IN the great pyramid of Giseh there
We're four such slabs In the passage lead
ing to the principal chamber, hit for
some reason, only one OF them had been
lowered. Yet 1t was only by cutting
around 1t through the masonry that The
explorers succeeded in reaching the hurial
and the passage in the pyramid
OF Aboukir was so well concealed nv n
similar slab that 1t was not discovered
until a shaft had been sunk to the center
of the structure.
There is a stone built in a retnininp wall
at Helicpolis, ancient Palmyra, of "A size
to make. our modern monoliths seem
small. 1t is some sixty feet long and ten
feet square. 1t Is used where smaller
blocks would have answered as well. 50
thar evidently the builders were not
greatly concerned about its size, although
1t is many feet up in the wall. The Ro-
mans who put 1t there, If it was the
Romans, must have used the same meth
DDS as the Egyptians, for they had nc
other appliances capable of handling such
a mass and it cannot be doubted that it
was dragged up an artificial slope and
lowered into place by removing the sane
Or earth under 1t. We may we'll wonder
why they should perform such a remark
able feat at such great pains to so little
purpose, but at the same time we can