Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1881-05-18
sudden Ingenuity.

There are times and occasions in the
lives of most individuals when sadder
call is made for the exercise OF readiness
or impromptu ingenuity, the Importance
of which may be very great, and which en-
sbles the possessor to make the best oi
such means and appliances as may be al
hand, no matter how unpromising or ap.
parently inapplicable.
A few years ago, an iron bridge of con.
siderable length, the weight being about
two hundred tons was constructed in this
country, and erected in a remote part of
Germany. By some mishap, the bridge,
when finished was found at some distance
out to one side, an error which the pro-
prietor insisted should be rectified. To
take down and reerect the bridge would be
simple ruin to the contractor. But Ne
cessity is the mother Of Invention, and 50
it proved In ills case. 1t was summer
time, and the contractor proceeded to find
the amount of expansion which was caused
by the heat of the sun over the whole
length of the bridge. He next ascertained
what contraction took rlace in the night
by cooling. Armed with these data, he
thought it might be possible to bring the
bridge to its proper position in few days.
The bridge of course, in Its ordinary con-
dition EXPANDED from the centre, pushing
its two ends outward, OF farther apart. and
again contracting towards the centre. TAX
ing advantage of these conditions, one end
was made fast in the morning and the
bridge was forced to expand from that i'm
movable point. instead of from the middle,
as formerly. When the iron composing
the bridge had expanded to its full extent
in the direction intended, that end was re-
leased, and the opposite end made fast. The
bridge then contracted towards its true
position. Thus, whatever was gained by
the days expansion, was secured by the
subsequent contraction when the metal
cooled at night; and the process being re-
newed day by day, the work was success
fully accomplished.
The walls of large building in Paris
were observed to be giving way by bulging
outwards; and the problem was to bring
them back to their vertical position. For
this purpose a number of bars of iron hav-
ing screws and nuts on each end were let
through the opposite walls, and across the
nuts and screwed portion OF the bars were
outside. The bars were new heated by
number of lamps suspended below them
until they had expanded as much as posi-
BILE, and the nut screwed up against the
outsides Of the two opposite walls. The
lamps were next removed; when the heated
bars in cooling gradually contracted in
their length, bringing the walls very gently,
but with irresistible force, into their nor
NAL position.
An old story is told in connection with
the expansion and contraction of materials
which may deserve place here as an i'll
ustration IN point. 1t has been stated that
when the Egyptian obelisk was being
erected IN the square in front of St. Peters
at Rome, in the year 1865 during the reign
of Pope Sixtus ", it was first demonstra-
ted that ropes under severe tension con-
tracted by the application of moisture. The
occasion was made one of high festival.
The architect and workman, and the other
obelisk also, received in state the benedic-
ton OF the Pope, and high mass was cele-
brated in st. Peters. But every attempt
to move the pillar was unsuccessful. All
the horses that could be found, with all
the Appliances for lifting heavy weights
of that tine, were put into requlsition. And
it was not until more than fifty unsuccess
full efforts had been made, that the huge
mass rose from the ground. Meanwhile,
the great weight stretched the ropes so
much, that when the pulley-blocks had
reached their limit in lifting, the bottom of
the obelisk had not reached the top of the
seat prepared for it. At that moment q
man in the crowd shouted: "Wet the
ropesI' The experiment was tried; the
ropes shrunk, and the obelisk gradually and
slowly rose ID the required height, and
was successfully placed on its seat.