The Manitowoc tribune. [volume] (Manitowoc, Wis.) 1866-1878, 1868-02-27
CIRInSITIES OF SnuNn.
Remarkable Observation-Disclosures Sounds
--Sympathetic Vibrations.
From Once a Wcek

To our limited understandings it some
times seems that nature delights in curl
Gus freaks: but when we come to analvze
her apparent vagaries they resolve them
selves into mere instances of the working
of simple laws. Imagine the whispered
secrets Of a confessional being proclaimed
to an unwilling nearer in distant part
4 of a cathedral. Such thing once occur
red in the Cathedral of Girgenti, in Sci
". A visitor to the edifce accidentally
came upon spot where he heard every
word that fair penitent was utterlng to
a closeted priest. IN remote quarter of
! the building. Here was a seeming freak;
but when the case came to be examined,
it was clear that the whispers were scat
tered over the curved roof, which, acting
like a concave reflector in the case of
light, converged the sounds to a focus
and SO the mystery revealed itself as an
instance of the conveyance of sound
| The eavesdropper used to delight in tax
! ing his friends to hear the revelations of
the penitents; but one day he and they
heard too much, for-unfortunate coinci-
dence his own wife knelt upon the
penitential stool and the betraying roof
made him acquainted with secrets any
| thing but amusing: the scandal that en-
sued brought about the removal of the
confessional to more secret spot. This
was not a case of mere echo: the sound
was actually brought to a focus at one
particular spot, just as the image of a
candle is projected upon wall by CON
cave reflector, or by a lens.
| OF remarkable echoes many are known
There Is the celebrated one in the Gap of
Dunloe, where the sounds are reflected
again and again, so that when a trumpet
Is blown at the proper the return notes
reach the ear in succession after one, two,
| three or more reflections from the ada
cent cliffs, and thus die away IN the
sweetest cadences. Alpine travellers, too
tell of wonderful warblings of echos in
the Swiss mountains. The rolling and
pealing Of thunder is due to echoes of
the primary clap, which are generally in
the clouds. A curious echo occurs at the
London Colosseum, Mr.. Wheatstone
| found that 4 syllable pronounced close to
| the upper part of the wall Of this stIuc-
| ture was repeated a great many times.
| 4 simple exclamation sounded like q peal
| OF laughter, and the tearing OF sheet OF
| paper ike the patter of hail.
Sound travels through the air at the
rate Of about 1,100 feet q second but
| this speed depends upon the elasticity
and density Of the air; and as the elias
! ITCHY depends upon temperature, 1t fol-
| lows that sound travels differently, ac-
cordingly as the air is warm or cold, At
freezing temperature its rate Is 900 feet
a second; at so deg. Fahrenheit, it is
| l,l40 feet. So that sound travels slower
In winter than in summer. Its velocity
| through other substances than air is also
very different. Through hydrogen gas it
is 4, 100 feet a second, and through water
a little greater than this. Iron conveys
it at nearly four times this speed.
In travelling through space sound di-
minishes in intensity, and, ike light and
other actions, it does this in proportion
to the square of the distance traversed.
\ man two yards from a bell only hears
one-fourth Of the sound that reaches an
ear one yard distant. X man three yards
off only catches one-ninth Of it; another
four yards distant a sixteenth, and so on.
The reason Of this rapid rate Of dininu-
ton and Of this inyariabie proportion is
obvious. If certain sound will fill a
sphere one yard III diameter with GER
tain intensity, that same sound, dispersed
through a sphere six yards in diameter,
and therefore spreading. over tAirty-slx
times as much space, viii be, as it We're,
diluted to thirty sixth Of its strength.
The leading Of sound through tubes
was practised in early times, and no
doubt speaking images and oracular re,
sponses depended upon this acoustical
phenomenon. In our own time we have
had talking heads. But modern sight
seers know all about tubes; so the heads
have been isolated from solid supports,
and carried by suspending chains. No
matter The mouth of the figure has
been made hollow, trumpet bell has
been placed in it; the sound has been
: led by tube to some concealed orifce di-
rectly in front of this bell-mouth, and
being as it were injected thereinto, has
been thrown out again towards the as
tonished audience, who have thus been
made to believe that the talking has been
the result of some highly ingenious me-
chanism contained within the image.
Nevertheless, successful attempts have
been made to initiate the human voice by
mechanical instruments. In the last
century, the Academy Of Sciences at St
Petersburg proposed as prize subject an
l inquiry into the nature of the yowe
sounds and the construction OF an lnstru
ment for artiicially initiating them. The
question was solved by NJ KratZentien
who showed that all the vowels could be
pronounced By blowing through a reed
into tubes Or chambers of various forms.
At about the same time a Niennese me
chanician, VI. Kempelen, made, made a
series of elaborate experiments which
led to the construction OF :. machine that
could be made TO utter not merely voca
sounds, but words, and even some few
complete sentences.
Sound is produced by certain vibrations
or pulsations communicated to the at
mosphere. When we pluck a harp
string we set it Quivering, and cause it tC
give to the adjacent air rapid succession
: of blows; the number of these blows il
9 second depending upon the length anc
tension of the string If the string only
gave one push TO the air, we should hear
bot one noise or blow; but, as IN vlbra
ting it gives rapid succession OF pushe!
we experience rapid succession OF nols
es, and these resolve themselves into 6
continuous sound.
Noises may become musical If only
they succeed each other at equal interval:
of time, and with sufficient rapldity. Il
watch could be caused to tick hun
dred times in a second, the ticks woulo
lose their individuality and blend into {
musical tone If the tapping OF pig
con 5 wings could be accomplished at tax
same rate, the bird would make music IN
its flight The humming bird does this
and do thousands Of insects whose wings
f vibrate with great rapidly. The high
ness or lowness, what we call the pitch, O
a sound, depends upon the Tapldlty viii
which these pulses fall upon the air
When they come at the rate of 50 or Ct
to ascend, we have deep growing bass
snnnH uhan st he rate of from twenty