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281
Heroes of the Telegraph
·
John Munro
65
Thomson
became
a
man
of
public
note
in
connection
with
the
laying
of
the
first
Atlantic
cable.
After
Cooke
and
Wheatstone
had
introduced
their
working
telegraph
in
1839;
the
idea
of
a
submarine
line
across
the
Atlantic
Ocean
began
to
dawn
on
the
minds
of
men
as
a
possible
triumph
of
the
future.
Morse
proclaimed
his
faith
in
it
as
early
as
the
year
1840,
and
in
1842
he
submerged
a
wire,
insulated
with
tarred
hemp
and
india-rubber,
in
the
water
of
New
York
harbour,
and
telegraphed
through
it.
The
following
autumn
Wheatstone
performed
a
similar
experiment
in
the
Bay
of
Swansea.
A
good
insulator
to
cover
the
wire
and
prevent
the
electricity
from
leaking
into
the
water
was
requisite
for
the
success
of
a
long
submarine
line.
India-rubber
had
been
tried
by
Jacobi,
the
Russian
electrician,
as
far
back
as
1811.
He
laid
a
wire
insulated
with
rubber
across
the
Neva
at
St.
Petersburg,
and
succeeded
in
firing
a
mine
by
an
electric
spark
sent
through
it;
but
india-rubber,
although
it
is
now
used
to
a
considerable
extent,
was
not
easy
to
manipulate
in
those
days.
Luckily
another
gum
which
could
be
melted
by
heat,
and
readily
applied
to
the
wire,
made
its
appearance.
Gutta-percha,
the
adhesive
juice
of
the
ISONANDRA
GUTTA
tree,
was
introduced
to
Europe
in
1842
by
Dr.
Montgomerie,
a
Scotch
surveyor
in
the
service
of
the
East
India
Company.
Twenty
years
before
he
had
seen
whips
made
of
it
in
Singapore,
and
believed
that
it
would
be
useful
in
the
fabrication
of
surgical
apparatus.
Faraday
and
Wheatstone
soon
discovered
its
merits
as
an
insulator,
and
in
1845
the
latter
suggested
that
it
should
be
employed
to
cover
the
wire
which
it
was
proposed
to
lay
from
Dover
to
Calais.
It
was
tried
on
a
wire
laid
across
the
Rhine
between
Deutz
and
Cologne.
In
1849
Mr.
C.
V.
Walker,
electrician
to
the
South
Eastern
Railway
Company,
submerged
a
wire
coated
with
it,
or,
as
it
is
technically
called,
a
gutta-percha
core,
along
the
coast
off
Dover.
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