Yorkville enquirer. [volume] (Yorkville, S.C.) 1855-2006, 1902-09-13

calling attention to one or more danger
which is threatening the Negro at this
time; that is, the drug habit-New
York Medical Record.
WHEN BRIDGES BREATHE.
How Iron Expands In Summer and
Contracts In Winter.
Though to speak Of bridges breathing
appears passing strange, nevertheless,
inanimate structures are never still
for moment during the livelong day
The Britannia bridge, for instance,
which Is 400 feet long under normal
circumstances. is from half to 3 inches
longer at 3 p m, than it is at IL hours
later. according to the amount Of sum
shine 1t Is subjected to. which draws
It sometimes an inch upward II the
heat strikes the top Of the tube, or to
one side when the sun increases its
temperature laterally. though the heav-
lest train will only bend 1t half an inch
at any time. In like manner intense
cold will cause bridge to shrink more
appreciably.
To show how intense the cold must
have been, we have only to point out
that Southwark bridge over the
Thames. which, however, is only about
one ninth the length of Brooklyn
bridge, only rose in the centre to the
amount Of II inches for so degrees rise
In temperature. To allow for expan-
sion or construction the builder of the
Clifton suspension bridge provided the
ends Of the roadway with hinged flaps
| 8 feet long, which allow Of perfect
freedom Of movement; and the makers
Of the tower bridge, which is about
q inches longer in the summer than
in the winter, made a similar allow.
ance.
After the choir of Bristol Cathedral
was covered with sheet lead in 1851, 1t
was discovered two years later that.
Notwithstanding the fact that the
length Of the covering was go feet, and
its depth 1Sa feet, 1t had crawled down
bodily for IS inches, drawing out nails
from the rafters in its course which had
been driven in to arrest its progress.
The explanation Of the movement lies
in the fact that the lead naturally ex-
panded more freely downward than
upward when subjected to the suns
heat, and that when It contracted at
night it drew its upper edge after it, in
preference to climbing up to it.
The Eiffel tower. like the Britannia
bridge. is ever on the move, either up
ward or downward, according to the
temperature, the summit Of the tower,
so it Is said, entailing an extra climb
of five inches when the temperature
is high than in the cool Of the
day, while in winter 1t is inches short
er than at midsummer. Even the
white marble obelisk dedicated to
Washington, which was erected at
cost Of 9260,OOO rears its head 555 feet
in heigth on the bank Of the Potomac,
Is not proof against the power Of the
sun, and Is said to increase its height
by inches and to bend slightly on a
hot day.
With regard to The latter movement,
a copper wire 174 feet long. carrying a
plummet suspended in vessel Of wa
ter, renders perceptible the slight bend
Of the shaft caused by the rays Of the
sun pouring on one side only. though
the inclination Of the apex Of the mon
ument amounts to but a few hum
dredths Of an inch toward the north
each day at noon throughout the sum-
mer.
The railway line is very powerful
respirator. Probably every Answerite
has noticed the gap between each rail.
In winter the chink will be over 4 quar-
ter Of an inch in width, but in summer
it will be quite closed up. During one
Of the frequent civil wars incidental to
South America one of the belligerents
conceived unique idea Of train wreck
ing. During the night he drove steel
wedges tightly into these gaps for a
considerable distance. The heat Of the
sun next day caused the rails to
breathe heavily but as they could not
expand longitudinally they twisted
themselves clean out Of the chairs
which clamped them to the sleepers
and the railway was rendered complete
ly useless for traffic.
A battleship is over inches longer III
summer than in winter, and an IRON
clad in The tropics is neariy foot long
er than her sister ship in a more north
ern sea. One of the most powerful
breathing materials employed for en-
gineering work is concrete. The .aque-
duct for the conveyance Of the water
for London, extending from Bell Wier
to Hampton, a distance Of about eight
and three-quarters mles, Is provided
with what are technica,iv termed ex~
pansion joints, at intervals Of 80 feet to
enable the material to breath.
ROOSEVELT AND THE TRUsTs.-Wm. ].
Bryan evidently takes but little stock
in President Roosevelts antitrust
speeches. In the last issue Of The Com
moner he has this to say.
"A Republican must be dull indeed
ha