when pronounced as in _bat_, in the three systems of registration.
That corresponding to line A is an enlarged reproduction of the
tracing left on the tinfoil; that corresponding to line B represents
its profile on the sheet of smoked glass. Finally, line C shows the
outline of Koenig’s singing flames, when the same sound is produced
quite close to the membrane of the register. It must be quite close,
since the form of the tracing produced by a pointer attached to a
vibrating membrane, when influenced by composite sounds, depends on
the distance intervening between the membrane and the source of sound,
and an infinite variety in the form of the tracing may be obtained
by modifying the distance. In fact, when this distance is increased,
the waves of sound which result from composite sounds react on the
membrane at different moments of their emission. For example, if the
composite sound is formed of six harmonics, the displacement of the
source of vibration from the first harmonic by ¼ the length of a wave
will respectively remove the second, third, fourth, fifth, and sixth
harmonics ½, ¾, 1, 1¼, 1½ the length of a wave, and consequently the
outline resulting from the combination of waves will no longer be
the same as it was before the displacement of the source of sound,
although the perception of the sounds remains the same in both cases.
This principle is clearly demonstrated by Koenig’s instrument, by
lengthening and shortening an extensible tube, inserted between the
resonator and the vibrating membrane, which is placed close to the
flame; and this explains the disagreement of physicists as to the
composition of vocal sounds which they have analysed by means of the
singing flames.
Mr. Mayer adds that these facts further show that we cannot hope to
read the impressions and tracings of the phonograph, which not only
vary with the nature of the voice, but also with the different moments
at which the harmonics of the voice are emitted, and with the relative
differences in the intensities of these harmonics.
Notwithstanding this assertion, we reproduce (fig. 72) an extremely
curious tracing sent to us by Mr. Blake, which represents the
vibrations produced by the words ‘Brown, University: how do you do?’
They were photographed by means of an index fastened to a vibrating
disk on which a ray of light was thrown. The word ‘how’ is particularly
remarkable for the combined forms of the inflections of the vibrations.
Recent experiments seem to show that the more the vibrating membrane
of the phonograph resembles the human ear in its construction, the
better it repeats and registers the sound vibrations: it should be
stretched, as far as possible, in the same way as the tympanum is
stretched by the hammer of the ear, and moreover it should have the
same form, since the vibrations of air are in this case much more
effective.
[Illustration: FIG. 72.]
Mr. Edison considers that the size of the opening of the mouthpiece has
considerable influence on the distinct articulation of speech. When
the sounds are pronounced before the whole surface of the diaphragm,
some hissing sounds are lost. They are, on the contrary, intensified
when these sounds reach the diaphragm through a narrow orifice with
sharp rims. If the opening is toothed on its flattened rims, the
hissing consonants are delivered more clearly. Speech is reproduced
more perfectly when the mouthpiece has a covering of some thickness,
so arranged as to deaden the sounds arising from the friction of the
tracing point on the tin.
Mr. Hardy has rendered the registration of phonographic tracings more
easy by adding a small ebonite tube, resembling the mouthpiece of a
wind instrument, to the mouthpiece of the phonograph.
USES OF THE PHONOGRAPH AND ITS FUTURE.
Mr. Edison has lately published in the ‘North American Review’ of
May-June 1878 an article on the future of the phonograph, in which he
himself discusses the different applications which may be made of this
instrument. Without sharing all his anticipations, which appear to us
to be very premature, we think that some extracts from his paper may be
interesting.
‘In order to furnish a basis on which the reader may take his stand ...
a few categorical questions and answers are given upon the essential
features of the principle involved.
‘1. Is a vibrating plate or disk capable of receiving a complex motion
which shall correctly represent the peculiar property of each and all
the multifarious vocal and other sound waves?
‘The telephone answers affirmatively.
‘2. Can such complex movement be transmitted from such plate by means
of a single embossing point attached thereto, to effect a record upon a
plastic material, by indentation, with such fidelity as to give to such
indentations the same varied and complex form? And if so, will this
embossing point, upon being passed over the record thus made, follow
it with such fidelity as to transmit to the disk the same variety of
movement, and thus effect a restoration or reproduction of the vocal or
other sound waves, without loss of any property essential to producing
on the ear the same sensation as if coming direct from the original
source?
‘The answer to this may be summed up in a statement of the fact that
... the writer has at various times during the past weeks reproduced
these waves with such degree of accuracy in each and every detail as
to enable his assistants to read, without the loss of a word, one or
more columns of a newspaper article unfamiliar to them, and which
were spoken into the apparatus when they were not present. The only
perceptible loss was found to be in the quality of the utterance, a
non-essential in the practical application of the instrument. Indeed,
the articulation of some individuals has been perceptibly improved by
passage through the phonograph, the original utterance being mutilated
by some imperfection of lip and mouth formation, and these mutilations
corrected or eliminated by the mechanism of the phonograph.[21]
‘3. Can a record be removed from the apparatus on which it was made,
and replaced upon a second without mutilation or loss of effective
power to vibrate the second plate?
‘This is a mere mechanical detail, presenting no greater obstacle
than having proper regard for the perfect interchangeableness of the
various working parts of the apparatus--not so nice a problem as the
manufacture of the American watch.
‘4. What as to the facility of placing and removing the second sheet,
and as to its transportation by mail?
‘But ten or fifteen seconds suffice for such placing or removing. A
special envelope will probably be required, the weight and form of
which, however, will but slightly increase the cost of postage.
‘5. What as to durability?
‘Repeated experiments have proved that the indentations possess
wonderful enduring power, even when the reproduction has been effected
by the comparatively rigid plate used for their production. It is
proposed, however, to use a more flexible plate for reproducing,
which, with a perfectly smooth stone point--diamond or sapphire--will
render the record capable of from fifty to one hundred repetitions,
enough for all practical purposes.
‘6. What as to duplication of a record and its permanence?
‘Many experiments have been made, with more or less success, in
the effort to obtain electrotypes of a record, and the writer is
informed that it has very recently been successfully accomplished. He
can certainly see no great practical obstacle in the way. This, of
course, permits of an indefinite multiplication of a record, and its
preservation for all time.
‘7. What is the requisite force of wave impinging upon the diaphragm,
and the proximity of the mouth to the diaphragm, to effect a record?
‘These depend in great measure upon the volume of sound desired in
the reproduction. If the reproduction is to be made audible to an
assembly, considerable force is requisite in the original utterance;
if for the individual ear, only the ordinary conversational tone (even
a whisper has been reproduced). In both cases the original utterances
are delivered directly in the mouthpiece of the instrument. An audible
reproduction may, however, be had by speaking at the instrument from a
distance of from two to three feet in loud tone. The application of a
flaring tube or funnel to collect the sound waves, and the construction
of an especially delicate diaphragm and embossing point, &c., are the
simple means which suggest themselves to effect this....
‘The foregoing presentment of the stage of development reached by the
several essential features of the phonograph demonstrates the following
_faits accomplis_:
‘1. The captivity of all manner of sound waves, hitherto designated as
“fugitive,” and their retention.
‘2. Their reproduction with all their original characteristics, without
the presence or consent of the original source, and after the lapse of
any period of time.
‘3. The transmission of such captive sounds through the ordinary
channels of commercial intercourse and trade in a material form, for
purposes of communication.
‘4. Indefinite multiplication and preservation of such sounds, without
regard to the existence or non-existence of the original source.
‘5. The captivation of sounds, with or without the knowledge or consent
of the source of their origin...
‘The apparatus now being perfected in mechanical details will be the
standard phonograph, and may be used for all purposes, except such
as require special form of matrix, such as toys, clocks, &c., for
an indefinite repetition of the same thing. The main utility of the
phonograph being, however, for the purposes of letter-writing and
other forms of dictation, the design is made with a view to its utility
for that purpose.
‘The general principles of construction are, a flat plate or disk, with
spiral groove on the face, worked by clockwork underneath the plate;
the grooves are cut very closely together, so as to give a great total
length to each length of surface--a close calculation gives as the
capacity of each sheet of foil nearly 40,000 words. The sheets being
but ten inches square, the cost is so trifling that but a hundred words
might be put on a single sheet economically....
‘The practical application of this form of phonograph is very simple.
A sheet of foil is placed in the phonograph, the clockwork set in
motion, and the matter dictated into the mouthpiece without other
effort than when dictating to a stenographer. It is then removed,
placed in suitable form of envelope, and sent through the ordinary
channels to the correspondent for whom it is designed. He, placing it
upon his phonograph, starts his clockwork, and _listens_ to what his
correspondent has to say.’
Since this paper by Mr. Edison appeared in June 1878, he has applied
the phonograph to several other purposes, among which we may mention
that of registering the force of sounds on railways, and especially
on the metropolitan atmospheric railway in New York. The instrument
which he has made for this purpose resembles that by Mr. Leo Scott, and
bears the same name. It is described and represented in the ‘Daily
Graphic’ of July 19, 1878, as well as the aerophone, the megaphone, and
the microtasimeter, which is adapted for astronomical observations. We
should exceed the limits laid down for this volume, if we were to give
a more detailed account of these inventions.
M. Lambrigot, one of the officials on the telegraphic lines in France,
and the author of various improvements in the Caselli telegraph, has
shown me a phonographic system of his own invention in which it is
reduced to its simplest form. He sent me the following description of
his system.
‘The instrument consists of a wooden slab placed vertically on a stand
and firmly fixed upon it. There is a round opening in the middle of the
slab, covered by a tightly stretched sheet of parchment bearing a steel
knife, which, like the tracing point of the phonograph, is intended to
trace the vibrations. A solid block rises from the stand to the middle
of the slab, and supports a slide on which a runner can move in front
of the slab. There is a strip of glass on this runner, of which one
side is covered with stearine. When the runner is moved to and fro, the
stearine comes in contact with the knife and takes the mould of its
form, which is curved throughout.
‘A sound places the sheet of parchment in vibration, and imparts its
movement to the knife, which traces various lines on the surface of
the stearine.
‘The reproduction thus obtained on the strip of glass is subjected to
the ordinary processes of metallisation. By galvanism a deposit of
copper is obtained which reproduces the lines in an inverse way. In
order to make the metallic plate speak, it is necessary to pass a point
of ivory, wood, or horn lightly over the signs, and, by moving it more
or less quickly, the different tones can be heard, just as they were
spoken.
‘Since copper is relatively harder than lead, the copper plate on
which the vibrations are traced will afford an unlimited number of
reproductions. To obtain this result, a lead wire must be applied
to the plate, and due pressure must be exerted on it. The wire is
flattened and takes the impression of all the traces which then appear
in relief. If the edge of a card is passed through this impressed
tracing, the same sounds are produced as those which are obtained from
the copper plate.’
M. Lambrigot suggests that the speaking plates might be useful in
many ways: for example, they might make it easy to learn the correct
pronunciation of foreign languages, since a sufficient number might be
collected to make a sort of vocabulary which would give the accent of
the words most in use in a given language.
By this simple process M. Lambrigot has been able to obtain a strong
impression, within a copper groove, of the vibrations caused by the
voice, and they are so distinctly engraved that whole sentences may be
heard, if they are retraced by the sharpened point of a match. It is
true that the reproduction is imperfect, and that those words are only
to be distinguished which were previously known; but it is possible
that better results will be obtained from improvements in the system,
and at any rate the distinct impression of the vibrations of the voice
on a hard metal is a really interesting discovery.
I have made one somewhat important observation in the working of the
phonograph--namely, that if speech is registered on the instrument
in a very hot room, and it is then carried to a colder room, the
reproduction of speech is imperfect in proportion to the difference
of temperature. This is probably owing to considerable modifications
in the elasticity of the caoutchouc pad which is inserted between the
tracing point and the vibrating disk: perhaps differences of expansion
in the tinfoil have also some effect.
FABER’S AMERICAN SPEAKING MACHINE.
About two years ago the newspapers announced with some pomp that a
speaking machine had reached Paris, which far surpassed Vaucanson’s
duck, and which would attract general attention. Unfortunately the
invention was not in the first instance brought forward with any
scientific authority, and was soon relegated to take a place among
the curiosities exhibited by conjurors. In a country so essentially
critical and sceptical as France, there are always those who profess
incredulity, and who will even resist evidence, and it was asserted
that the machine only spoke because its exhibitor was an able
ventriloquist. This is an old assertion which has lately been made
with reference to the phonograph. Some scientific papers echoed the
absurdity, and the speaking machine was so discredited that it is now
unnoticed, although it is a most ingenious and interesting conception.
When will our country be cured of the error of denying everything
without due examination?
Since we ourselves only judge of things after having seriously
considered them, we think it just to vindicate the truth as to Mr.
Faber’s machine, and this can only be done by an exact description of
it.
As I said in the last chapter, there is a great difference between
the production and the reproduction of a sound, and a machine
like the phonograph, adapted for the reproduction of sound, may
differ essentially from a machine which really speaks. In fact, the
reproduction even of articulate sounds may be very simple, as soon as
we possess the means of stereotyping the vibrations of air necessary to
transmit these sounds; but in order to produce them, and especially to
emit the complex vibrations which constitute speech, it is necessary
to set in motion a number of special organs, fulfilling more or less
exactly the functions of the larynx, the mouth, the tongue, the lips,
and even the nose. For this reason, a speaking machine is necessarily
very complicated, and this is precisely the case with the machine we
are now considering. Such a machine is not now made for the first time,
and the Academy has lately been reminded of a speaking head which was
in the possession of the philosopher Albertus Magnus in the thirteenth
century, and which was destroyed by St. Thomas Aquinas as a diabolical
invention.
Mr. Faber’s speaking machine was exhibited two years ago at the Grand
Hôtel, and may now be seen in the room adjoining M. Robert Houdin’s
theatre, the same room in which Mr. Giffard exhibited the telephone. It
consists of three distinct parts: 1st, of a large bellows worked by a
pedal, which produces the currents of air necessary for the production
of sounds, and to some extent acts as the lungs; 2nd, a vocal
instrument, consisting of a larynx accompanied by diaphragms of various
forms to modify the sounds, of a mouth with caoutchouc lips and tongue,
and of a tube with an outlet somewhat resembling the nasal cavities;
3rd, of a system of jointed levers and of pedals, terminating in keys
like those of a piano.
The most interesting part of the machinery, of which we represent the
principle fig. 73, is the vocal apparatus, which involved the severest
study of physics in order to succeed in the production of articulate
sounds. It consists, first, of a rather thick caoutchouc tube, within
which there is a kind of whistle L, as in a clarionet. The whistle
consists of a small caoutchouc cylinder with a longitudinal slit, and
before this is placed a very thin ivory plate lined with caoutchouc.
This plate is fixed at one end to the cylinder, and deviates slightly
from it at its free end, so as to permit the current of air projected
from the bellows S to penetrate between the two parts, and to cause the
vibrations in the ivory plate necessary for the production of a sound.
The extremity of the caoutchouc cylinder is closed on this side, and is
fitted to an iron rod _t_ which comes out of the pipe, and is connected
with a system of bars, corresponding to the keyboard of a piano, by
which the force of sounds can be regulated. This force depends on the
width of the opening between the tongue and the cylinder.
[Illustration: FIG. 73.]
The whistle, which plays the part of the larynx, is necessarily placed
opposite the opening of the bellows, and a sort of tourniquet M is
fastened to the opening itself, which is able to move on certain
conditions, so that it may produce the rolling sound of _r_. This is
done by fastening before the opening a diaphragm in which there is a
somewhat wide and long slit, and this slit can be almost closed by a
little bar of the same size M, revolving on a transverse axis which
supports it by its centre. In its normal condition, this little bar is
kept in a slanting position by cords attached to the keyboard, and the
air ejected by the bellows readily traverses the slit in order to reach
the larynx; but two dampers are fastened to the rods which transmit
movement, with which the cords just mentioned are also connected. On
lowering the notes of the key-board, the passage of air is contracted,
and the little plate begins to oscillate and to press against a band of
leather, producing by its vibration an action similar to that produced
by the cricket. This little tourniquet only begins to act when the
dampers are lowered by a pedal worked by the hand; and this is also
the case with the iron rod _t_, which modifies the acuteness of the
sounds passing through the larynx.[22]
Below the larynx tube, which is only five centimètres in length,
there is another pipe G, also of caoutchouc, which terminates in a
spherical cavity connected with the outer air by a caoutchouc tube I,
slightly raised, and closed by a valve, of which the movements are
regulated by a pedal worked by the keyboard. When the valve is open,
the sounds emitted through the larynx are somewhat nasal.[23] The
larynx communicates with the mouth through a square funnel-shaped pipe,
to which six metallic diaphragms D are fastened; the diaphragms are
placed in a vertical position behind each other, and have indentations
on their lower end, which are intended to diminish more or less the
orifice for the current of air, and to impede its passage with greater
or less force. The diaphragms, which we represent separately fig. 74,
are connected with the keyboard by jointed iron rods _t_, and, for the
emission of most articulate sounds, several of the diaphragms are
moved at the same moment and at different heights. We shall return to
this subject.
[Illustration: FIG. 74.]
The mouth consists of a caoutchouc cavity O, somewhat resembling the
human mouth, and forming a continuation to the channel we have just
described. The tongue C, likewise modelled on the human tongue, is
placed within the mouth, and connected with two jointed rods _t_,
_t_, fastened to its two opposite ends, so as to enable the tongue to
raise its tip, or touch the palate, in obedience to the notes of the
keyboard. The lower caoutchouc lip A can also be more or less closed,
according to the action of the keyboard on its special rod. Finally,
a circular metallic piece E, following the shape of the mouth, is
placed above the upper lip, with a small opening in it to admit of the
pronunciation of the letter _f_.
The keyboard has fourteen notes, of different lengths, producing the
following letters when lowered, _a_, _o_, _u_, _i_, _e_, _l_, _r_,
_v_, _f_, _s_, _ch_, _b_, _d_, _g_. The longest corresponds to _g_,
and the shortest to _a_. There are two pedals below the _g_ note and
those of _b_ and _d_, corresponding with the opening of the tube which
produces nasal sounds, and to the rod which regulates the opening of
the larynx, and this makes it possible to obtain _p_, _t_, and _k_ from
the notes _b_, _d_, _g_. The mechanical effects produced by lowering
the different notes in succession are as follows:--
1. The _a_ note moves the first five diaphragms.
2. _o_ also moves these five diaphragms, but varies the pitch, and
closes the mouth a little.
3. _u_ does the same, only further closing the mouth.
4. _t_ moves a single diaphragm, raises the tip of the tongue, and
opens the mouth more widely.
5. _e_ moves six diaphragms, throws the tongue further back, and opens
the mouth still more.
6. _l_ moves five diaphragms, sends the tongue against the palate, and
further opens the mouth.
7. _r_ moves six diaphragms and the tourniquet, lowers the tongue, and
somewhat closes the mouth.
8. _v_ moves five diaphragms, almost closes the mouth, and keeps the
tongue down.
9. _f_ lowers the circular appendix of the upper lip, and almost
entirely closes the mouth.
10. _s_ moves three diaphragms, half closes the mouth, and half raises
the tongue.
11. _ch_ moves three diaphragms, keeps the mouth half closed, and
further lowers the tongue.
12. _b_ moves five diaphragms, closes the mouth, and keeps the tongue
completely down.
13. _d_ moves six diaphragms, keeps the mouth three parts closed, and
raises the tongue a little.
14. _g_ moves five diaphragms, keeps the mouth three parts closed, and
the tongue completely down.
_m_ is produced by lowering note _b_ and opening the valve of the pipe
which gives nasal sounds.
_n_ is obtained by lowering note _d_ and opening the same valve.
_h_ is obtained from note _s_ by lowering the pedal which acts upon the
larynx, and half closing it.
Since the other letters of the alphabet are compound sounds, they can
be produced by combinations of the preceding letters.