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281
Heroes of the Telegraph
·
John Munro
181
'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.
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