Wessington Springs herald. (Wessington Springs, Aurora County, Dakota [S.D.]) 1883-1891, 1888-02-17
Some Strange and Interesting
Facts in Natural Phi
4 losophy
now xUslC EFFECTS A BRIDGE.
Tie Little Non Conscience Will Alwavs
Tell Us the Right Thing
to DO.
Cwr.sssssss Of so.ssa a.a vibration.

stion, and the bridge has not time to re-;
cover between the steps Hence dur.
ing the passage Of troops and all we'll
regulated professions over bridge.
the music il stopped and the ranks
broken, so that the weight Of the crowd
is evenly distributed, while some are
putting their feet down others are lift
ing theirs up. Sometimes fearful &C.
Scidents have followed when this break
ing Of step has not besn observed.
Once in France very long bridge went
down undera tody Of soldiers march
ing over in ranks, resulting in the death
sofnearly hundred persons. There is
far less danger when q bridge IS crowded
with people or cattle, or even many.
heavily laden cars, than when . few
persons are walking over keeping step
The combination of force is SO great
and vibrations would increase to that
extent that q small dog could ruin the
finest and largest bridge if he could
trot back and forth, continually keep
ing exact time.
Il We stand near piano and produce
. musical tone with the voice, it will be
noticed that one particular string will
select that sound and respond to it.
Open the mouth wider. or make the
sound deeper in the chest or at a higher
pitch, and the first string will cease,
while another string in the same key as
the voice will take up the strain. II .
hundred tuning forks Of different tones
are sounding at the foot Of an organ
pipe, il will choose the one in accord
with ii, and respond in that key alone.
The sound called the song Of the Sea,
so often heard when shells are placed
close to the ear, is merely the vibrations
of the air within the she'll, and the two
shells placed with their bells near the
ear will increase the roar IL the vibra-
ton Of the air within is in unison or
sympathy. The same increase may be
seen with two tuning-forks; but il the
vibrations are different, the one will
counterfeit the other, like the proces-
sion marching ont Of step. and no sound
will be heard perfectly. Other sub
stances than air will convey the sound
waves; q faint scratch on one end Of q
long log may be distinctly heard at the
other end, or stroke on the end Of .
long piece Of tightly stretched metal
bit Of copper wire will communicate
the shock to the other end many hum
bred feet away.
Whena bell rings, the tongue strik-
ing the side of tho bell starts . sound
wave that swellsg gradually until the ear
is reached, just as the little wave which,
stone has disturbed increases in size,
until it reaches the shore. IF, when
the tongue strikes, the bell is touching
any other substance, q discordant wave
is started which will destroy the one
beforesi il, cutting it up, as il were, as
the small wave started OF another point
from where we first threw the stone
will meet and @chop" the other, and q
calm ensues. A continuous blast Of air
produces no sound, any more than q
stationary stake in still water will pro-
duce waves, but let the pillows Of air or
water strike an obstruction, and sound
or waves are seen. HMper,s, Young
{ People. 81;