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281
Heroes of the Telegraph
·
John Munro
182
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.
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