b1629371X_1370_117_2

NATURAL MAGIC.
John Nevil Maskelyne
IV.—Acoustics.
The science of acoustics, though little cultivated, is a most valuable one. Sound does not, by any means, “signify nothing,” for we owe some of our most pleasing sensations to it. The power of audibly communicating our thoughts, or of appreciating music, is only truly estimated, indeed, by those who have once enjoyed it and then been deprived by deafness of the blessing.
All sound is vibration, and sonorous air-waves travel in ever-widening circles exactly as rings form in water when a pebble is dropped therein; but it can be deflected from its course, obeying much the same laws as light, and presenting some curious effects that come within the scope of our subject. Thus Echo, “the daughter of the voice,” is a potent oily in magical arts; she lurks in buildings, grottoes, rocks, forests, and rivers,—
By whose falls
Melodious birds sing madrigals,”
and is ever ready mockingly to repeat our words. When the reflecting surface is at such a distance from us that the original and return sounds are not blended, the phenomenon is at its best. At Lurley-Feis, upon the Rhine, the voice is reproduced by echo seventeen times; and at the Villa Simonetta, near Milan, there are thirty or more reverberations.  
Dr. Plot speaks of an echo in Woodstock Park that bas the peculiarity of repeating seventeen syllable8 by day and twenty by night. The most noted cavern echo was that at Syracuse, in Sicily. This cave was called the ‘‘ Ear of Dionysins,” and it is said to have been a natural ear-trumpet. Here the tyrant placed his prisoners, whose lightest words could be heard b the sentinel without.
One of the most marvellous of echoes is at none. eva doors in the \Vhispering Gallery of St. Paul’s Cathedral. Here you turn your face to the wall and spsale in a low tone, and the words will be heard upon the opposite side of the dome, but not at any intermeclists point. The East Gallery of Gloucester Cathedral has a remarkable echo, as also has the Abbey Church of St. Albans; and the Hall of Secrete, in the Observatory, Paris, gives another striking example sf this class of phenomena.
Some of the reflections of sound here named ate natural, others artificial. A very curious echo ef the latter sort is in the famous Baptistry of Pisa. Sir David Brewster observes that “the architect, file. vanni Pisani, is said to have thus constructed the cupola on purpose. The Pisan cupola has an elliptical form, and when one person whispers in the one focus it is distinctly heard by the person placed in the other focus, but not by those who are placed between them. The sound first reflected passes senses the cupola and enters the ears of the intermediate person, but it is too feeble to be heard till it has been condensed by a second reflection to the ether focus of the ellipse.”
In the cathedral of Girgenti, Sicily, a whisper is carried a distance of two hundred and fifty feet. It seems that the focus of one of the reflecting surface was, by a malapropos choice, selected for the confessional, and some persons aware of the effect resented to the other focus to gather the scandalous secrete entrusted by the penitent to the ghostly fathers. It is proverbial that listeners seldom or never hear any good of or for themselves, and it proved so en thin occasion, for one of the eavesdroppers, when his wife came to be shriven, listened to the recital of some confessions that led to a domestic catastrophe, and to the revelation of the strange acoustical properties of the building.
The celebrated Marquis of Worcester, the inventor of the steam-engine in its primitive form (the “fire engine” used at Ffoxhall [Vauxhall] waterworks in 1670), utilised his knowledge of the reflection of seunod, according to Dr. W. Hooper, in the construction of a speaking-machine upon thie principle; and undoubtedly it can be accomplished, as Sir David Brewster observes,” by means of two concave mirrors placed directly opposite to each other, so that the head of the assistant may be in one of the foci, and the rnesth of the trumpet in the other, a hole being made an the partition between the assistant and the figure, corresponding in size and situation to the mirrors, an filled up by a very thin cloth to prevent suspn000fl. This scarcely, in my view, meets the marquis’s ides, which he thus mentions in his “ Century of Inventions”“ How to make a brazen or stone hand, in the midst of a great field or garden, so artificial and natural that though a man speak never so softly into the ear thereof; it will presently open its mouth and resolve the question in French, Latin, Welsh, Irish, or English, in good terms, uttering it out of its mouth, and then shut it until the next quashes 55 asked.”
Hers we find the machine is to be placed in an
open space, and ht is difficult to imagine the reflectors
would work as in an enclosed place. It is much
more likely that the marquis used tubes by which
sound can be conveyed for long distances and by
devious ways. Even such devices were enigmas once,
but they have now left the region of the wonderful
for the more steady, if not so brilliant, line of usefulness, performing valuable offices by putting top-floor
and basement of our largest hotels and warehouses
upon friendly speaking terms.
The first “speaking figure” that we can refer to
with certainty as worked upon this principle, was
the property of one Irsou, an English conjuror, who
exhibited the marvellous creation before Charles m.
It caused great surprise by its ready and pertinent
answers to his Majesty, but one of the pages unfortunately stumbled across the juggler’s accomplice in
an adjoining apartment, speaking through a tube
connected with the figure. The most successful illusion
of this kind was that produced in Paris by feE.
Charles, about 1825, and subsequently in London,
and known as “The Invisible Girl.” Fig. 1 represents this machine in perspective; it was a fixture
in the centre of the floor. A hollow copper ball,
about one foot in diameter, woo suspended by ribbons
from the four bent wires springing from the outer
supports, and to the ball wore affixed four trumpets
with their mouths outwards. The lips being placed
near any of those, a g was sent, and the
answer came back ho, apparently, a child’s voice, but
quits audible to those who listened at any of the
trumpet-mouths. It in needless to say now that the
lady operator sat in another room, and the messages
to or from her were conveyed from or to the
trumpet-mouths by means of a pipe laid beneath
the flooring and passing concealed through the
framework td the trumpets. Several other speaking machines—genuine efforts at obtaining words by mechanism, and tricks—will be included in my papers
upon “Automata.”

Wood is a good conductor of sound, especially deals and other light varieties. The stethoscope, invented by Lasmac, in 1819, by which we can listen to the heart’s action, is simply a wooden cylinder. The scratch of a pin on one end of a fallen tree, though so slight that the person who makes it hears no sound. may be noticed at the other end by applying one’s ear to the trunk of the tree. Sir Charles Wheatstone carried a concert from the cellar to the garret of a house by means of four deal rods. The lower ends of these rested respectively upon a piano, violin, violoncello, and a clarinet, and they carried the music from these instruments to elastic sounding- boards in “the parlour that’s next to the sky,” whose vibrations made a murmuring ‘i’ the air” of such strange beauty as to be only comparable to the strains to which, it may be supposed, fairies trip it on the grass.
Sound is likewise conducted by the forehead or teeth through the bony parts of the head. By holding the opposite extremities of a thin piece of wood between their teeth two persons may converse in low tones at some distance from each other, or if you lay your watch upon the table, and retire from it so far as to be out of hearing, its tick will be rendered audible if you take one end of the stick in your teeth and place the other and upon the watch—this, too, though you hold your hands over your ears. So, if you fill your ears with cotton and put your fingers to the teeth of one who speaks (not between them, please), you will hear his voice. String will also conduct sound when held between the teeth by two persona; and a “boy’s own telegraph” may be constructed by our juveniles without expense. Let them cut the remaining and out of a tin can, such as preserved milk is sold in ; stretch a moistened piece of parchment across the aperture, which will tighten like a drumhead when dry. In the middle of this make a small hole and pass a string through it, leaving a knot upon the end which will not go through this aperture. Then at the other end of the twins, which may be a few yards in length, place another can similarly arranged to the previous one. A whisper into the can at one sod will be heard by the listener whose sac is applied to the can at the other. If our young friends wish also to bring the tones of the minster bell to their own firesides, they can do so by tying a string round the handle of a poker. Leave two ends to the twine and hold one of these close to each ear, then let some one give the poker a smart blow with a stick.
The boy’s telegraph has been named, but the magician’s use of the real electric wire for such purposes has not yet been touched upon. Fertile in expedients as is the roady-witted master of “hankypanky,” he would yet be occasionally at a loss for novelties unless he walked hand in hand with science. Electricity, which almost beats time, is really made to do so by the conjuror, who enlists it into his service for his magic drum, his goblin cymbals, and his fairy bells; and it is his henchman, tried and true, when he deceives the cars and eyes of his audience by throwing marked coins into “Aladdin’s Crystal Cash- box,” suspended from the ceiling. There cannot be any mistake about it l You see the professor go through the action of throwing, and you hear the chink 0f the money as it drops by some mysterious means within the glass. Also l we could not quite
“see through” that fair-seeming crystal casket; for
before it had been brought upon the stage the marked coins had been conveyed off, and shut securely, and )
invisible to the spectator, within its false top. When
the casket is slung in the air the wizard. apparently
throws the real coins towards it, but really only
“palms” representative ones. The motion of throwing imposes upon the eyes and misleads the imaginations of the spectators. At the same moment an electric current passes along the wire and releases the
spring confining the false top to its position, and the
complete the deception; and very curious it is to the
uninitiated when one’s wn crooked. sixpence is found
coins thus liberated fall with a rattle on the glass to
within the box. On the same principle “spirit rap-
ping” can be heard at any place to which electricity
can pass by a wire to move a bidden hammer.
to the world. of science, is in the Telephone. Acoustics
The latest marvel, and the most magical addition
and electricity united have achieved the seemingly
impossible in the electrical transmission of the human
voice. The telegraph had “gone on circuit” of the
inventions had been known for a long time also,
earth for a goodly number of years, and Koenig’s
before it struck any one that the wires might he
made vocal. Koenig made what he called a Phonautograph
over the end of a trumpet and provided with a flexible
at the other, and the point by these means wrote a
musical air of seven notes. The same genius also
point. A note sounded at one end caused vibrations
produced ‘Koenig’s flames,” by which the visible
qresph, which was a membranous covering stretched
image of the timbre, or quality of sound of the
voice, was called forth. His voice in this case acted
to the jet of flame, making it rise and fall. The
upon a membrane, whose vibrations were as a bellows
famous philosopher, Dr. Robert bole, of Fresh-
water, in the Isle of Wight, had visions of the telephone two hundred years ago, but he was before the
d’d S r Charles Wheatstone nearer our own time,
a’e of the electrical girdle. Hooke experimented, as
with light wooden rods carrying the sounds to thin
vibrating boards. When he placed musical-boxes in
padded chests so that no sound escaped, he could yet
convey the tones to a distant sounding-board. by his
wooden rods. But Dr. Hooke was a little in advance
of the times, like Roger Bacon, the Marquis of Worcester, and some others. For the benefit of those
who wish to make experiments in private, I may
name an excellent trick upon this principle, which
causes much astonishment to the uninitiated. Two
Place one within a padded box in an upper room, and
musical-boxes playing the same airs are required.
pass a wire connected with it through the floor and
the ceiling of the apartment beneath. At the lower
end of the wire bang an empty deal box. Now
lower room shall be set going to some particular air,
your duplicate musical box upon the table in this
and. when it is concluded the same strains may be
heard proceeding from the empty box; for by some
pre-arranged signal your confederate has started the
musical-box in the upper room, and the sound is
conveyed. down the wire into the box beneath. The
first idea of the telephone dawned upon Herr Reiss,
a German, in 1852. His original instrument was the
hollowed-out hung of a beer-barrel closed with the
skin of a Strasbourg sausage. A strip of platinum,
fixed in its position by scaling-wax, “made” or
sounding-board. He afterwards made a wooden box
“broke” the electric circuit. The receiving instrument was a knitting-needle with wire wound round
it, and. this was placed. upon a violin, which acted as a with a trumpet mouth. On the top of this box Wa
round hole covered with. a bladder, and. on it5 upper
surface a sheet of thin metal connected with a galvanic battery. When any one spoke through the
trumpet the vibrations interrupted the current
gave out the same sounds at one end that ere
spoken into it at the other.
This was more scientific, if less powerful, than that
apocryphal speaking-trumpet mentioned by Kheher,
the soldiers received orders from their commander
when he was ten or twelve miles off! Even this fahu.
—“the Horn of Alexander,”—by means of Which
bus transmitter of vocal sounds has been left a long
march in the rear by the latest (the “ articulating”)
telephone of Professor Graham Bell, an English
tone and pitch of the voice, but its timbre also, sn
naturalised American, which not alone convey5 this
that with telegraphic, not mechanical, speed. Round
one end of a bar-magnet insulated wire is wound,
and the ends of this are connected with screws in the
to earth,” the other connected with the telegraph
small end of the box. A wire from one screw is “run
Between the hole, where is fixed a trumpet-mun
and the magnet, is a very thin disc of soft iron—.
graph wire has a precisely similar arrangement
iron disc vibrating, and a current passing along the
wire repeats the sounds in every particular—to ens
Speaking into the mouth-piece at one end. sets the
whose ear is to the trumpet at the other end—ease
“the drum of the ear.” The other end of the tale.
in being lower in tone; exactly, in fact, as if sie
spoke through a tube.
lessor Bell’s beautiful invention in its patented fern
The prohibitive royalty fixed upon the use of Pro.
puts it outside all ordinary pursuits, but there li
nothing to prevent persons having it for their private
use, and moot opticians will furnish you with the
Professor Barrett has shown how we can ourselves
instrument at a moderate price.
make a telephone at the cost of a few pence. A
wooden tooth-powder box has a hole cut through Iii
twcen them; a small, straight bar-magnet is pat
through n silk or small cotton-reel, and fixed near
the disc, and round. the reel wire is wound. This ii
and bottom; a disc of tinned. iron is fastened be.
the “originator,” and the “receiver” is similar.
Some trials will be needed to adjust the distances,
but the wire between originator and receiver may
extend for some hundred yards.
oat mention of that kind of familiar spirit which
No article upon acoustics would. be complete with-
some men carry about with them. This is Ventriloquism and if its possessor be also a spirit medium,
he finds it a valuable addition to his craft. Indeed,
being enamoured of a rich heiress, conceived the idea
one Louis Brabant, cczlct-dc-chasmbro to Francis I,
of receiving a direct spirit message from her deceased
father, and his art was so potent that the lady’s
mother accepted the supposed spirit-command that
Louis should marry the heiress. The romance eod8,
as such stories usually do, with the union of the
lovers, so we are not informed whether Madame
Brabant was happily mated or not, but it was a bad
beginning to end. well, we should say. VeatriOqUi1
is said to be the power of producing sound from the
larynx without the muscles of the face being mssd,
cases as far as my observation extend. The effects
and that strength is given to such sounds by a powerful action of the abdominal muscles. This maybe
so, but the face is never quite motionless ira each
depend lees upon the performer’s power of imitation
than in his knowledge of the actions and tricks of
manner by which he directs attention to the spot frono
hrce the sounds are supposed to proceed. The oft-
asserted power of t,hpswieg the voice is an absurdity;
in fact, the difference in the pitch of the voice, by
which the sounds are made to come as from a die-
tanre, deceives the ear, while the illusion is completed by the gestures of the performer.
The amusing talking dolls we sometimes see are
much easier to work than ordinary ventriloquism,
where the voice has apparently to be thrown. This
is mimicry pure and simple, and the dolls being so
to the performer the words can be produced
with little or no movements of the muscles of the
face. All kinds of sounds have boon imitated by
clever ventriloquists. Mr. Love ran through the
gamut of the whole farmyard and stable vocabulary,
from the high-mottled racer to Noddy Bray, Mr.
Both, Madame Dun Cow, Master Calf, pigs, ducks,
and ehaxatirleer. Mr. Thurton’e “Odd Polka” wore
hig My amusing, and his ventriloquial production of
the cheering of a crowd was a remarkable achieve-
meet. Thurton, indeed, was the greatest artist in
his line in our time. Neither of these gentlemen,
however, were so great as some performers in the
past, if we may credit all that hoe been elated of
them, which is hazardous. In the “Memoirs of the
Empress Josephine” an anecdote is related of one
Thiemet, a ventriloquist, at the time creating considerable aeneation in Pane. He wan invited to the
house of Eugene Beauharnaie, where were met to
breakfast a gay circle of young officers. Of these,
“first one and then another heard himself distinctly
called out of the room by the voice of his nerving-
man, mntll the whole party had in torn made a fruit-
ieee expeditien downstairs. Each returned more
amazed than another, and it was finally resolved to
sally forth in a body. Thiemet, who, not personally
known, save as a guest, to any of the party, had all
this time continued quietly seated at table, opening
his lips only to eat or drink, functions which he
seemed to perform with great address, new rose to
assist in the search of the invieible serving-men. No
sooner had the party reached the hail than the calls,
apparently from all different quarters, were repeated.
Each scampered off in various pursuit of the cup-
culprit, crying out, ‘Hero! here’s the rascal!’
till, in the inexplicable confusion, Eugene’s laud
laugh discovered the whole plot. The greater part
received it as a ‘passably excellent joke,’ but enme
there were disposed to bestow the chaetioement of the
innocent valets en the guilty professor.”
Even a mere amusing story is told of another
French ventriloquist, which may take rank with
Theodore Heek’e famous hoax for its fan, and is
without the more disagreeable consequence of that
rather ill-natured frolic. It is related of Alexandre, the ventriloquist in question, that passing
one day near the new defunct Temple Bar he
observed a large load of hay struggling through the
gateway. He instantly imitated the cries of a suffocating man, and drew the attention of the passers-by
to the muffled sounds. The cart was stopped in its
most inconvenient position, and a crowd of persons
assisted to unload the hay, the cries of the supposed
man within growing fast and furious as the mob
worked with redoubled energy. Just as they were
getting to the bottom of the cart the moaning ceased,
and the workers gave up the man as dead, though still proceeding to throw the hay into the roadway
the stoppage of all traffic. The cause of the silence,
however, was not the sudden decease of the supposed
entombed man, but the discreet exit of the ventriloquial joker, who retired before the denouement of the drama.