We have heretofore given accounts of the wonderful success of
Professor Bell in transmitting the vibrations of the human voice by
electrical means over a telegraph wire. He has lately made
improvements in his method of transmission, by which he dispenses with
the use of the battery, and substitutes the magneto-electric plan of
producing the current. The Boston _Transcript_ describes a recent
experiment with the new apparatus, by which conversation and singing
was successfully carried on between Boston and Malden, a distance of
six miles. The telephone, in its present form, consists of a powerful
compound permanent magnet, to the poles of which are attached ordinary
telegraph coils of insulated wire. In front of the poles, surrounded
by these coils of wire, is placed a diaphragm of iron. A mouthpiece to
converge the sound upon this diaphragm substantially completes the
arrangement. As is well known, the motion of steel or iron in front of
the poles of a magnet creates a current of electricity in coils
surrounding the poles of the magnet, and the duration of this current
of electricity coincides with the duration of the motion of the steel
or iron moved or vibrated in the proximity of the magnet. When the
human voice causes the diaphragm to vibrate, electrical undulations
are induced in the coils environing the magnets, precisely analogous
to the undulations of the air produced by that voice. These coils are
connected with the line wire, which may be of any length, provided the
insulation be good. The undulations which are induced in these coils
travel through the line wire, and, passing through the coils of an
instrument of precisely similar construction at the distant station,
are again resolved into air undulations by the diaphragm of this
instrument.
The experiments were as follows: Telephones having been connected with
the private telegraphic line of the Boston Rubber Shoe Company,
conversation was at once commenced. Stationed at the Boston end of the
wire, Professor Bell requested Mr. Watson, who was at the Malden end,
to speak in loud tones, with a view of enabling the entire company at
once to distinguish the sounds.
This was so successful that a smile of mingled pleasure and surprise
played on the features of those present. That it, however, might not
be supposed that loud speaking was essential to intelligibility, Mr.
Bell explained that soft tones could be heard across the wires even
more distinctly than loud utterances, even a whisper being audible. In
confirmation of this statement, Mr. Watson commenced speaking in turn
with each member of the company; and after the efficiency of this
method had been proved to the satisfaction of all, he took up a
newspaper and informed the assemblage that gold had closed the
previous evening at New York at 105-5/8. As there were quite a number
of business men present, the effect that this practical demonstration
of the value of the telephone produced can scarcely be exaggerated.
Other passages from the daily journals were then given, and by this
time the desire for conversation having become general, Mr. Watson was
plied with questions such as: "Is it thawing or freezing at Malden?
Who will be the next President?" etc. It was remarkable that Mr.
Watson was able to distinguish between the voices at the Boston end,
he calling at least one gentleman by name as soon as the latter
commenced speaking.
This went on for some time, until a lady at the Malden end sent the
company an invitation to lunch per telephone, and an appropriate
response was made by the same medium. At length the Boston company
were requested to remain quiet while a lady at the other end conveyed
to them the sweet strains of music. The assemblage thereupon listened
with rapt attention while a young lady commenced singing "The Last
Rose of Summer." The effect was simply charming. The sound of the
voice penetrated into the Boston end of the telephone with a
distinctness equal to that attainable in the more distant parts of a
large concert room, and a unanimous vote of thanks was sent by the
handy little instrument which had procured for the assemblage so
agreeable an hour.
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The superb steam engine built by C.H. Brown & Co., of Fitchburg,
Mass., which was illustrated and described on page 1 of our current
volume, has been purchased by Messrs. Phineas Jones & Co., and is
being erected in their extensive carriage wheel works at Newark, N.J.
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