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Heroes of the Telegraph
·
John Munro
24
In
1840
Wheatstone
had
patented
an
alphabetical
telegraph,
or,
'Wheatstone
A
B
C
instrument,'
which
moved
with
a
step-by-step
motion,
and
showed
the
letters
of
the
message
upon
a
dial.
The
same
principle
was
utilised
in
his
type-printing
telegraph,
patented
in
1841.
This
was
the
first
apparatus
which
printed
a
telegram
in
type.
It
was
worked
by
two
circuits,
and
as
the
type
revolved
a
hammer,
actuated
by
the
current,
pressed
the
required
letter
on
the
paper.
In
1840
Wheatstone
also
brought
out
his
magneto-electrical
machine
for
generating
continuous
currents,
and
his
chronoscope,
for
measuring
minute
intervals
of
time,
which
was
used
in
determining
the
speed
of
a
bullet
or
the
passage
of
a
star.
In
this
apparatus
an
electric
current
actuated
an
electro-magnet,
which
noted
the
instant
of
an
occurrence
by
means
of
a
pencil
on
a
moving
paper.
It
is
said
to
have
been
capable
of
distinguishing
1/7300
part
of
a
second,
and
the
time
a
body
took
to
fall
from
a
height
of
one
inch.
The
same
year
he
was
awarded
the
Royal
Medal
of
the
Royal
Society
for
his
explanation
of
binocular
vision,
a
research
which
led
him
to
construct
the
stereoscope.
He
showed
that
our
impression
of
solidity
is
gained
by
the
combination
in
the
mind
of
two
separate
pictures
of
an
object
taken
by
both
of
our
eyes
from
different
points
of
view.
Thus,
in
the
stereoscope,
an
arrangement
of
lenses
and
mirrors,
two
photographs
of
the
same
object
taken
from
different
points
are
so
combined
as
to
make
the
object
stand
out
with
a
solid
aspect.
Sir
David
Brewster
improved
the
stereoscope
by
dispensing
with
the
mirrors,
and
bringing
it
into
its
existing
form.
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