Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-01-24
TALKS into MODEL
OF BELL INVENTION
Mrs. Grosvenor, Daughter of
Telephone Magnate, Speaks
at Geographic Meeting.

Mrs. Gilbert GroSvenor, daughter Of
Alexander Graham Bell, last night
spoke into model Of the original tele-
phone instrument her father invented
before an audience Of members Of the
National Geographic Society, Of which
her father was one Of the founders.
Mrs. Grosvenor's brief acknowledge
ment of the invitation, spoken into the
historic instrument, which Is the most
highly priced exhibit of the Bell
Research Laboratory's Museum, was
amplifled by one Of the most modern
devices so that it was plainly audible
to every one of the 1000 auditors.
The occasion was the address by DR..
Sergius p. Grace, vice president of the
Bell Telephone Laboratories, who told
of the vast development of telephone
communication, from the date when
DR.. Bell spoke the first complete and
ineligible sentence ever received by
the electrical telephone, March 10,
1875, until now, when myriad wires
are carrying constant streams of con-
versations across continents and under
the oceans.
nAStOEAC WHG DSpLdycus
Another historic exhibit shown by
DR.. Grace was a few yards Of the wire
over which DR.. Bell spoke his famous
sentence to Thomas A. Watson. This
wire was utilized last night to demon
strate another recent and marvellous
development-it carried the impulse by
which, when dial telephone Is used, q
mechanical voice is made to utter, in
the telephone exchange, the numbers
dialed. This synthetic, or mechanical
voice, pronounceS the words without the
Intervention of the human voice.
DR.. Grace then exhibited a section
Of the worlds newest telephone cable,
that which has been laid between Key
West and Havana. wherein is used the
new insulating material, "paragutta,"
which helps the cable carry three or
four times the electrical word traffic
handled by cables of earlier design.
DR.. Grace did not limit his talk TO
telephone communication, but also
showed many of the amazing devices
which have been developed as a study
of telephone and collateral means Of
communication. Some Of these are yet
only of scientific interest. having no
present practical application.
Singing Arc" Demonstrated.
One of the most spectacular demon
STATIONS was of "the singing arc" An
ordinary flaming arc lamp was made to
serve in place of a complicated loud
speaker. Electrical voice and musical vi
brationS were led along wires to the
two carbons Of the arc, and from the
fame thus thrown into pulsations the
sounds issued as from an ordinary am
plifier.
In one of his experiments DR.. Grace
made metal bar float above block of
wood. The floating bar, highly mag
netized, was kept in the air by the re-
pulsive force of a magnet hidden in the
block. DR.. Grace then took a long rod
Of permalloy, metal originated by the
laboratories, and showed that it Is so
highly sensitive to the earth's mag
netiSm that 1t becomes a magnet when
held in north and south direction and
loses its magnetism when pointing east
and west.
Ordinary speech was scrambled by
being passed through one of the devices
on the stage so that 1t came from the
loud speakers as a meaningless tumble
OF sounds. Passage through another
piece OF apparatus 'unscrambled" the
speech so that 1t became ineligible.
The system Is used, the speaker ex-
planned, to keep tranSoceanic converse
tons secret. Another phenomenon made
use OF in radio telephony and demon
strated by DR.. Grace is delayed or res
ervoired" speech. The spoken words
or their Vtbrations-are bottled uo in a
wire for fraction of second and then
permitted to go on their way. During
the tiny delay important RELAYS are
gwen an opportunity to operate.