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Heroes of the Telegraph
·
John Munro
5
This
idea
was
perhaps
the
basis
of
the
sympathetic
telegraph
of
the
Middle
Ages,
which
is
first
described
in
the
MAGIAE
NATURALIS
of
John
Baptista
Porta,
published
at
Naples
in
1558.
It
was
supposed
by
Porta
and
others
after
him
that
two
similar
needles
touched
by
the
same
lodestone
were
sympathetic,
so
that,
although
far
apart,
if
both
were
freely
balanced,
a
movement
of
one
was
imitated
by
the
other.
By
encircling
each
balanced
needle
with
an
alphabet,
the
sympathetic
telegraph
was
obtained.
Although
based
on
error,
and
opposed
by
Cabeus
and
others,
this
fascinating
notion
continued
to
crop
up
even
to
the
days
of
Addison.
It
was
a
prophetic
shadow
of
the
coming
invention.
In
the
SCEPSIS
SCIENTIFICA,
published
in
1665,
Joseph
Glanvil
wrote,
'to
confer
at
the
distance
of
the
Indies
by
sympathetic
conveyances
may
be
as
usual
to
future
times
as
to
us
in
literary
correspondence.'
[The
Rosicrucians
also
believed
that
if
two
persons
transplanted
pieces
of
their
flesh
into
each
other,
and
tattooed
the
grafts
with
letters,
a
sympathetic
telegraph
could
be
established
by
pricking
the
letters.]
Dr.
Gilbert,
physician
to
Queen
Elizabeth,
by
his
systematic
researches,
discovered
the
magnetism
of
the
earth,
and
laid
the
foundations
of
the
modern
science
of
electricity
and
magnetism.
Otto
von
Guericke,
burgomaster
of
Magdeburg,
invented
the
electrical
machine
for
generating
large
quantities
of
the
electric
fire.
Stephen
Gray,
a
pensioner
of
the
Charterhouse,
conveyed
the
fire
to
a
distance
along
a
line
of
pack
thread,
and
showed
that
some
bodies
conducted
electricity,
while
others
insulated
it.
Dufay
proved
that
there
were
two
qualities
of
electricity,
now
called
positive
and
negative,
and
that
each
kind
repelled
the
like,
but
attracted
the
unlike.
Von
Kleist,
a
cathedral
dean
of
Kamm,
in
Pomerania,
or
at
all
events
Cuneus,
a
burgher,
and
Muschenbroek,
a
professor
of
Leyden,
discovered
the
Leyden
jar
for
holding
a
charge
of
electricity;
and
Franklin
demonstrated
the
identity
of
electricity
and
lightning.
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