The first to produce a practicable speaking telephone was Alexander
Graham Bell. He was born at Edinburgh on March 1, 1847, and comes of
a family associated with the teaching of elocution. His grandfather in
London, his uncle in Dublin, and his father, Mr. Andrew Melville Bell,
in Edinburgh, were all professed elocutionists. The latter has published
a variety of works on the subject, several of which are well known,
especially his treatise on Visible Speech, which appeared in Edinburgh
in 1868. In this he explains his ingenious method of instructing deaf
mutes, by means of their eyesight, how to articulate words, and also
how to read what other persons are saying by the motions of their lips.
Graham Bell, his distinguished son, was educated at the high school of
Edinburgh, and subsequently at Warzburg, in Germany, where he obtained
the degree of Ph.D. (Doctor of Philosophy). While still in Scotland he
is said to have turned his attention to the science of acoustics, with a
view to ameliorate the deafness of his mother.
In 1873 he accompanied his father to Montreal, in Canada, where he was
employed in teaching the system of visible speech. The elder Bell was
invited to introduce it into a large day-school for mutes at Boston, but
he declined the post in favour of his son, who soon became famous in the
United States for his success in this important work. He published more
than one treatise on the subject at Washington, and it is, we believe,
mainly through his efforts that thousands of deaf mutes in America are
now able to speak almost, if not quite, as well as those who are able to
hear.
Before he left Scotland Mr. Graham Bell had turned his attention to
telephony, and in Canada he designed a piano which could transmit its
music to a distance by means of electricity. At Boston he continued his
researches in the same field, and endeavoured to produce a telephone
which would not only send musical notes, but articulate speech.
If it be interesting to trace the evolution of an animal from its
rudimentary germ through the lower phases to the perfect organism, it
is almost as interesting to follow an invention from the original model
through the faultier types to the finished apparatus.
In 1860 Philipp Reis, as we have seen, produced a telephone which could
transmit musical notes, and even a lisping word or two; and some ten
years later Mr. Cromwell Fleetwood Varley, F.R.S., a well-known English
electrician, patented a number of ingenious devices for applying the
musical telephone to transmit messages by dividing the notes into short
or long signals, after the Morse code, which could be interpreted by
the ear or by the eye in causing them to mark a moving paper. These
inventions were not put in practice; but four years afterwards Herr Paul
la Cour, a Danish inventor, experimented with a similar appliance on a
line of telegraph between Copenhagen and Fredericia in Jutland. In this
a vibrating tuning-fork interrupted the current, which, after traversing
the line, passed through an electro-magnet, and attracted the limbs of
another fork, making it strike a note like the transmitting fork. By
breaking up the note at the sending station with a signalling key, the
message was heard as a series of long and short hums. Moreover, the hums
were made to record themselves on paper by turning the electro-magnetic
receiver into a relay, which actuated a Morse printer by means of a
local battery.
Mr. Elisha Gray, of Chicago, also devised a tone telegraph of this kind
about the same time as Herr La Cour. In this apparatus a vibrating
steel tongue interrupted the current, which at the other end of the line
passed through the electro-magnet and vibrated a band or tongue of iron
near its poles. Gray's 'harmonic telegraph,' with the vibrating tongues
or reeds, was afterwards introduced on the lines of the Western Union
Telegraph Company in America. As more than one set of vibrations--that
is to say, more than one note--can be sent over the same wire
simultaneously, it is utilised as a 'multiplex' or many-ply telegraph,
conveying several messages through the same wire at once; and these can
either be interpreted by the sound, or the marks drawn on a ribbon of
travelling paper by a Morse recorder.
Gray also invented a 'physiological receiver,' which has a curious
history. Early in 1874 his nephew was playing with a small induction
coil, and, having connected one end of the secondary circuit to the zinc
lining of a bath, which was dry, he was holding the other end in his
left hand. While he rubbed the zinc with his right hand Gray noticed
that a sound proceeded from it, which had the pitch and quality of the
note emitted by the vibrating contact or electrotome of the coil. 'I
immediately took the electrode in my hand,' he writes, 'and, repeating
the operation, found to my astonishment that by rubbing hard and rapidly
I could make a much louder sound than the electrotome. I then changed
the pitch of the vibration, and found that the pitch of the sound under
my hand was also changed, agreeing with that of the vibration.'
Gray lost no time in applying this chance discovery by designing the
physiological receiver, which consists of a sounding-box having a zinc
face and mounted on an axle, so that it can be revolved by a handle. One
wire of the circuit is connected to the revolving zinc, and the other
wire is connected to the finger which rubs on the zinc. The sounds are
quite distinct, and would seem to be produced by a microphonic action
between the skin and the metal.
All these apparatus follow in the track of Reis and Bourseul--that is
to say, the interruption of the current by a vibrating contact. It
was fortunate for Bell that in working with his musical telephone an
accident drove him into a new path, which ultimately brought him to the
invention of a speaking telephone. He began his researches in 1874 with
a musical telephone, in which he employed the interrupted current to
vibrate the receiver, which consisted of an electro-magnet causing an
iron reed or tongue to vibrate; but, while trying it one day with his
assistant, Mr. Thomas A. Watson, it was found that a reed failed to
respond to the intermittent current. Mr. Bell desired his assistant,
who was at the other end of the line, to pluck the reed, thinking it
had stuck to the pole of the magnet. Mr. Watson complied, and to his
astonishment Bell observed that the corresponding reed at his end of the
line thereupon began to vibrate and emit the same note, although there
was no interrupted current to make it. A few experiments soon showed
that his reed had been set in vibration by the magneto-electric currents
induced in the line by the mere motion of the distant reed in the
neighbourhood of its magnet. This discovery led him to discard the
battery current altogether and rely upon the magneto-induction currents
of the reeds themselves. Moreover, it occurred to him that, since the
circuit was never broken, all the complex vibrations of speech might be
converted into sympathetic currents, which in turn would reproduce the
speech at a distance.
Reis had seen that an undulatory current was needed to transmit sounds
in perfection, especially vocal sounds; but his mode of producing the
undulations was defective from a mechanical and electrical point of
view. By forming 'waves' of magnetic disturbance near a coil of wire,
Professor Bell could generate corresponding waves of electricity in the
line so delicate and continuous that all the modulations of sound could
be reproduced at a distance.
As Professor of Vocal Physiology in the University of Boston, he was
engaged in training teachers in the art of instructing deaf mutes how to
speak, and experimented with the Leon Scott phonautograph in recording
the vibrations of speech. This apparatus consists essentially of a thin
membrane vibrated by the voice and carrying a light stylus, which traces
an undulatory line on a plate of smoked glass. The line is a graphic
representation of the vibrations of the membrane and the waves of sound
in the air.
On the suggestion of Dr. Clarence J. Blake, an eminent Boston aurist,
Professor Bell abandoned the phonautograph for the human ear, which it
resembled; and, having removed the stapes bone, moistened the drum with
glycerine and water, attached a stylus of hay to the nicus or anvil, and
obtained a beautiful series of curves in imitation of the vocal sounds.
The disproportion between the slight mass of the drum and the bones
it actuated, is said to have suggested to him the employment of
goldbeater's skin as membrane in his speaking telephone. Be this as it
may, he devised a receiver, consisting of a stretched diaphragm or drum
of this material having an armature of magnetised iron attached to its
middle, and free to vibrate in front of the pole of an electro-magnet in
circuit with the line.
This apparatus was completed on June 2, 1875, and the same day he
succeeded in transmitting SOUNDS and audible signals by magneto-electric
currents and without the aid of a battery. On July 1, 1875, he
instructed his assistant to make a second membrane-receiver which could
be used with the first, and a few days later they were tried together,
one at each end of the line, which ran from a room in the inventor's
house at Boston to the cellar underneath. Bell, in the room, held one
instrument in his hands, while Watson in the cellar listened at the
other. The inventor spoke into his instrument, 'Do you understand what
I say?' and we can imagine his delight when Mr. Watson rushed into the
room, under the influence of his excitement, and answered,'Yes.'
A finished instrument was then made, having a transmitter formed of
a double electro-magnet, in front of which a membrane, stretched on a
ring, carried an oblong piece of soft iron cemented to its middle. A
mouthpiece before the diaphragm directed the sounds upon it, and as
it vibrated with them, the soft iron 'armature' induced corresponding
currents in the cells of the electro-magnet. These currents after
traversing the line were passed through the receiver, which consisted
of a tubular electro-magnet, having one end partially closed by a thin
circular disc of soft iron fixed at one point to the end of the tube.
This receiver bore a resemblance to a cylindrical metal box with thick
sides, having a thin iron lid fastened to its mouth by a single screw.
When the undulatory current passed through the coil of this magnet, the
disc, or armature-lid, was put into vibration and the sounds evolved
from it.
The apparatus was exhibited at the Centennial Exhibition, Philadelphia,
in 1876, and at the meeting of the British Association in Glasgow,
during the autumn of that year, Sir William Thomson revealed its
existence to the European public. In describing his visit to the
Exhibition, he went on to say: 'In the Canadian department I heard,
"To be or not to be... there's the rub," through an electric wire;
but, scorning monosyllables, the electric articulation rose to higher
flights, and gave me passages taken at random from the New York
newspapers: "s.s. Cox has arrived" (I failed to make out the s.s. Cox);
"The City of New York," "Senator Morton," "The Senate has resolved to
print a thousand extra copies," "The Americans in London have resolved
to celebrate the coming Fourth of July!" All this my own ears heard
spoken to me with unmistakable distinctness by the then circular disc
armature of just such another little electro-magnet as this I hold in my
hand.'
To hear the immortal words of Shakespeare uttered by the small inanimate
voice which had been given to the world must indeed have been a rare
delight to the ardent soul of the great electrician.
The surprise created among the public at large by this unexpected
communication will be readily remembered. Except one or two inventors,
nobody had ever dreamed of a telegraph that could actually speak,
any more than they had ever fancied one that could see or feel; and
imagination grew busy in picturing the outcome of it. Since it was
practically equivalent to a limitless extension of the vocal powers,
the ingenious journalist soon conjured up an infinity of uses for the
telephone, and hailed the approaching time when ocean-parted friends
would be able to whisper to one another under the roaring billows of the
Atlantic. Curiosity, however, was not fully satisfied until Professor
Bell, the inventor of the instrument, himself showed it to British
audiences, and received the enthusiastic applause of his admiring
countrymen.
The primitive telephone has been greatly improved, the double
electro-magnet being replaced by a single bar magnet having a small coil
or bobbin of fine wire surrounding one pole, in front of which a thin
disc of ferrotype is fixed in a circular mouthpiece, and serves as a
combined membrane and armature. On speaking into the mouthpiece, the
iron diaphragm vibrates with the voice in the magnetic field of the
pole, and thereby excites the undulatory currents in the coil, which,
after travelling through the wire to the distant place, are received in
an identical apparatus. [This form was patented January 30, 1877.] In
traversing the coil of the latter they reinforce or weaken the magnetism
of the pole, and thus make the disc armature vibrate so as to give out
a mimesis of the original voice. The sounds are small and elfin, a minim
of speech, and only to be heard when the ear is close to the mouthpiece,
but they are remarkably distinct, and, in spite of a disguising twang,
due to the fundamental note of the disc itself, it is easy to recognise
the speaker.
This later form was publicly exhibited on May 4, 1877 at a lecture
given by Professor Bell in the Boston Music Hall. 'Going to the small
telephone box with its slender wire attachments,' says a report, 'Mr.
Bell coolly asked, as though addressing some one in an adjoining room,
"Mr. Watson, are you ready!" Mr. Watson, five miles away in Somerville,
promptly answered in the affirmative, and soon was heard a voice singing
"America."....Going to another instrument, connected by wire with
Providence, forty-three miles distant, Mr. Bell listened a moment, and
said, "Signor Brignolli, who is assisting at a concert in Providence
Music Hall, will now sing for us." In a moment the cadence of the
tenor's voice rose and fell, the sound being faint, sometimes lost, and
then again audible. Later, a cornet solo played in Somerville was very
distinctly heard. Still later, a three-part song floated over the
wire from the Somerville terminus, and Mr. Bell amused his audience
exceedingly by exclaiming, "I will switch off the song from one part of
the room to another, so that all can hear." At a subsequent lecture
in Salem, Massachusetts, communication was established with Boston,
eighteen miles distant, and Mr. Watson at the latter place sang "Auld
Lang Syne," the National Anthem, and "Hail Columbia," while the audience
at Salem joined in the chorus.'
Bell had overcome the difficulty which baffled Reis, and succeeded in
making the undulations of the current fit the vibrations of the voice
as a glove will fit the hand. But the articulation, though distinct, was
feeble, and it remained for Edison, by inventing the carbon transmitter,
and Hughes, by discovering the microphone, to render the telephone the
useful and widespread apparatus which we see it now.
Bell patented his speaking telephone in the United States at the
beginning of 1876, and by a strange coincidence, Mr. Elisha Gray applied
on the same day for another patent of a similar kind. Gray's transmitter
is supposed to have been suggested by the very old device known as
the 'lovers' telephone,' in which two diaphragms are joined by a taut
string, and in speaking against one the voice is conveyed through the
string, solely by mechanical vibration, to the other. Gray employed
electricity, and varied the strength of the current in conformity with
the voice by causing the diaphragm in vibrating to dip a metal probe
attached to its centre more or less deep into a well of conducting
liquid in circuit with the line. As the current passed from the probe
through the liquid to the line a greater or less thickness of liquid
intervened as the probe vibrated up and down, and thus the strength of
the current was regulated by the resistance offered to the passage of
the current. His receiver was an electro-magnet having an iron plate as
an armature capable of vibrating under the attractions of the varying
current. But Gray allowed his idea to slumber, whereas Bell continued
to perfect his apparatus. However, when Bell achieved an unmistakable
success, Gray brought a suit against him, which resulted in a
compromise, one public company acquiring both patents.
Bell's invention has been contested over and over again, and more than
one claimant for the honour and reward of being the original inventor
of the telephone have appeared. The most interesting case was that
of Signor Antonio Meucci, an Italian emigrant, who produced a mass of
evidence to show that in 1849, while in Havanna, Cuba, he experimented
with the view of transmitting speech by the electric current. He
continued his researches in 1852-3, and subsequently at Staten Island,
U.S.; and in 1860 deputed a friend visiting Europe to interest people
in his invention. In 1871 he filed a caveat in the United States Patent
Office, and tried to get Mr. Grant, President of the New York District
Telegraph Company, to give the apparatus a trial. Ill-health and
poverty, consequent on an injury due to an explosion on board the Staten
Island ferry boat Westfield, retarded his experiments, and prevented
him from completing his patent. Meucci's experimental apparatus was
exhibited at the Philadelphia Exhibition of 1884, and attracted much
attention. But the evidence he adduces in support of His early claims is
that of persons ignorant of electrical science, and the model shown
was not complete. The caveat of 1871 is indeed a reliable document; but
unfortunately for him it is not quite clear from it whether he employed
a 'lovers' telephone,' with a wire instead of a string, and joined a
battery to it in the hope of enhancing the effect. 'I employ,' he says,
'the well known conducting effect of continuous metallic conductors as
a medium for sound, and increase the effect by electrically insulating
both the conductor and the parties who are communicating. It forms
a speaking telegraph without the necessity of any hollow tube.' In
connection with the telephone he used an electric alarm. It is by
no means evident from this description that Meucci had devised a
practicable speaking telephone; but he may have been the first to employ
electricity in connection with the transmission of speech. [Meucci is
dead.]
'This crowning marvel of the electric telegraph,' as Sir William Thomson
happily expressed it, was followed by another invention in some respects
even more remarkable. During the winter of 1878 Professor Bell was
in England, and while lecturing at the Royal Institution, London, he
conceived the idea of the photophone. It was known that crystalline
selenium is a substance peculiarly sensitive to light, for when a ray
strikes it an electric current passes far more easily through it than if
it were kept in the dark. It therefore occurred to Professor Bell that
if a telephone were connected in circuit with the current, and the ray
of light falling on the selenium was eclipsed by means of the vibrations
of sound, the current would undulate in keeping with the light, and
the telephone would emit a corresponding note. In this way it might be
literally possible 'to hear a shadow fall athwart the stillness.'
He was not the first to entertain the idea, for in the summer of 1878,
one 'L. F. W.,' writing from Kew on June 3 to the scientific journal
NATURE describes an arrangement of the kind. To Professor Bell, in
conjunction with Mr. Summer Tainter, belongs the honour of having, by
dint of patient thought and labour, brought the photophone into material
existence. By constructing sensitive selenium cells through which the
current passed, then directing a powerful beam of light upon them, and
occulting it by a rotary screen, he was able to vary the strength of the
current in such a manner as to elicit musical tones from the telephone
in circuit with the cells. Moreover, by reflecting the beam from a
mirror upon the cells, and vibrating the mirror by the action of the
voice, he was able to reproduce the spoken words in the telephone. In
both cases the only connecting line between the transmitting screen or
mirror and the receiving cells and telephone was the ray of light. With
this apparatus, which reminds us of the invocation to Apollo in the
MARTYR OF ANTIOCH--
'Lord of the speaking lyre,
That with a touch of fire
Strik'st music which delays the charmed spheres.'
Professor Bell has accomplished the curious feat of speaking along a
beam of sunshine 830 feet long. The apparatus consisted of a transmitter
with a mouthpiece, conveying the sound of the voice to a silvered
diaphragm or mirror, which reflected the vibratory beam through a lens
towards the selenium receiver, which was simply a parabolic reflector,
in the focus of which was placed the selenium cells connected in
circuit with a battery and a pair of telephones, one for each ear.
The transmitter was placed in the top of the Franklin schoolhouse,
at Washington, and the receiver in the window of Professor Bell's
laboratory in L Street. 'It was impossible,' says the inventor,
'to converse by word of mouth across that distance; and while I was
observing Mr. Tainter, on the top of the schoolhouse, almost blinded by
the light which was coming in at the window of my laboratory, and vainly
trying to understand the gestures he was making to me at that great
distance, the thought occurred to me to listen to the telephones
connected with the selenium receiver. Mr. Tainter saw me disappear from
the window, and at once spoke to the transmitter. I heard him distinctly
say, "Mr. Bell, if you hear what I say, come to the window and wave your
hat!" It is needless to say with what gusto I obeyed.'
The spectroscope has demonstrated the truth of the poet, who said that
'light is the voice of the stars,' and we have it on the authority
of Professor Bell and M. Janssen, the celebrated astronomer, that the
changing brightness of the photosphere, as produced by solar hurricanes,
has produced a feeble echo in the photophone.
Pursuing these researches, Professor Bell discovered that not only
the selenium cell, but simple discs of wood, glass, metal, ivory,
india-rubber, and so on, yielded a distinct note when the intermittent
ray of light fell upon them. Crystals of sulphate of copper, chips
of pine, and even tobacco-smoke, in a test-tube held before the beam,
emitted a musical tone. With a thin disc of vulcanite as receiver, the
dark heat rays which pass through an opaque screen were found to yield a
note. Even the outer ear is itself a receiver, for when the intermittent
beam is focussed in the cavity a faint musical tone is heard.
Another research of Professor Bell was that in which he undertook to
localise the assassin's bullet in the body of the lamented President
Garfield. In 1879 Professor Hughes brought out his beautiful induction
balance, and the following year Professor Bell, who had already worked
in the same field, consulted him by telegraph as to the best mode of
applying the balance to determining the place of the bullet, which had
hitherto escaped the probes of the President's physicians. Professor
Hughes advised him by telegraph, and with this and other assistance an
apparatus was devised which indicated the locality of the ball. A full
account of his experiments was given in a paper read before the American
Association for the Advancement of Science in August, 1882.
Professor Bell continues to reside in the United States, of which he is
a naturalised citizen. He is married to a daughter of Mr. Gardiner G.
Hubbard, who in 1860, when she was four years of age, lost her hearing
by an illness, but has learned to converse by the Horace-Mann system of
watching the lips. Both he and his father-in-law (who had a pecuniary
interest in his patents) have made princely fortunes by the introduction
of the telephone.