The Columbia Democrat. [volume] (Bloomsburg, Pa.) 1837-1850, 1842-11-19
EFFECTS OF EXPANSION.

A cannon ball when heated, cannot be
made to enter an opening through which,
when cod,h passes iapdly. A glass STOP
per sticking fast in the neck of a bottle, may
be released by surrounding the neck, with
a cloth taken out os warm water, or BY i'm
mersing the bottle in ,he wafer up 10 the
neck. The binding rirg is thus heated and
expanded sooner than the stopper, and 30
becomes slack or loose upon il. Pipes .or
conveying hot wafer, steam, hot air, &c. II
of considerable length. must have Jennings
.hat allow a degree Of shortening and length.
ening. otherwise change Of Temperature
may destroy them. An incompetent per.
son undertook TO warm largo manufsctory
by steam from one boiler. He laid rigid
main pipe along a passage. aud opened
lateral branches .hIough holes into the sew.
eral apartments; but, ON his frs, admilliDg
the steam, the expansion Of the main pipe
tore il away from VII 49, 49,
iron railing. gate which, during a cold day
may be loose, and easily shut or opened. in
warm day may stick, owing 10 their being
greater expansion of it and of the nelgbor-
ing railing. than of the earth on which they
are placed. Thus, also, The centre Of the
arch Of an iron bridge is higher in warm
Than in cold weather, while, on the contra.
ry, in a suspension or chain bridge, Ike
centre is lowered. The iron pillars now so
much used 10 support the irsn. walls Of
houses, Of which the ground stories serve
as shops with spacious windows, in warm
weather really lift up the wall which rests
upon them, and in cold weather allow i.
t.,a aink a,,h,,ha in Aarron .on,:A
eraLly greater than if the wall were brick
from top TO bottom. The pitch Of piano
forte is slowered in q warm day, or in a
warm room, owing 10 the expansion Of the
strings being greater than The wooden
frsmewOik; and in cold the reverse will
happen. A harp or piano, which 10 well
toned IN a morning drawingroom, canno, be
perfectly in tune when the crowded evening
party has heated the room. Beliwires, loo
slack in summer, may DO of the proper
length ia winter There exists most sx-
,raordinary exception, already mentioned, 10
the law of expansion by heat and icon,rac-
ton by cold. producing unspeakable bsne-
fits in nsture--namely,i in the case of wafer.
w ater contracts, according to the law, only
down 10 the temperature Of forty degrees,
while, from ,ha. TO ,hirty.two degrees,
which is ito freezing peint, il again dIiates.
| A very curious consequence Of this peculi.
srity is exhibited in the wells Of the glaciers
Of Switzerland and elsewhere, that when
once pool or shallow we'll on the ice
commences, it goes on quickly deepening
itself until il peuetra.es to the earth beneath
Supposing she snrface of the wafer origin
ally TO have nearly tho temperature Of tn,
melting ice, or thriy-two degrees, bu, TO bs
afterwards heated by the hes, & sun, ,ins,est
of the water being thereby dilated, or spe
officially higher and detained a, the surface
il becomes heavier the more nearly il il
heated to forty degrees. and therefore sink
down 10 the bottom Of The pit, or well, bu
there, by dissolving some Of the ice; ant
being consequently cooled, il 10 sgain rem
dersd lighter, and rises. to be heated as be
fore, again 10 descend, and this circulation
and digging canno, cease until tho wafer ha
bored its way quite through. -..drnoH.