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Heroes of the Telegraph
·
John Munro
10
In
1833-5
Professors
Gauss
and
Weber
constructed
a
telegraph
between
the
physical
cabinet
and
the
Observatory
of
the
University
of
Gottingen.
At
first
they
used
the
voltaic
pile,
but
abandoned
it
in
favour
of
Faraday's
recent
discovery
that
electricity
could
be
generated
in
a
wire
by
the
motion
of
a
magnet.
The
magnetic
key
with
which
the
message
was
sent
Produced
by
its
action
an
electric
current
which,
after
traversing
the
line,
passed
through
a
coil
and
deflected
a
suspended
magnet
to
the
right
or
left,
according
to
the
direction
of
the
current.
A
mirror
attached
to
the
suspension
magnified
the
movement
of
the
needle,
and
indicated
the
signals
after
the
manner
of
the
Thomson
mirror
galvanometer.
This
telegraph,
which
was
large
and
clumsy,
was
nevertheless
used
not
only
for
scientific,
but
for
general
correspondence.
Steinheil,
of
Munich,
simplified
it,
and
added
an
alarm
in
the
form
of
a
bell.
In
1836,
Steinheil
also
devised
a
recording
telegraph,
in
which
the
movable
needles
indicated
the
message
by
marking
dots
and
dashes
with
printer's
ink
on
a
ribbon
of
travelling
paper,
according
to
an
artificial
code
in
which
the
fewest
signs
were
given
to
the
commonest
letters
in
the
German
language.
With
this
apparatus
the
message
was
registered
at
the
rate
of
six
words
a
minute.
The
early
experimenters,
as
we
have
seen,
especially
Salva,
had
utilised
the
ground
as
the
return
part
of
the
circuit;
and
Salva
had
proposed
to
use
it
on
his
telegraph,
but
Steinheil
was
the
first
to
demonstrate
its
practical
value.
In
trying,
on
the
suggestion
of
Gauss,
to
employ
the
rails
of
the
Nurenberg
to
Furth
railway
as
the
conducting
line
for
a
telegraph
in
the
year
1838,
he
found
they
would
not
serve;
but
the
failure
led
him
to
employ
the
earth
as
the
return
half
of
the
circuit.
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