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281
Heroes of the Telegraph
·
John Munro
89
The
ink,
for
example,
is
like
a
highly-charged
thunder-cloud
supported
over
the
earth's
surface.
Now
the
tendency
of
a
charged
body
is
to
move
from
a
place
of
higher
to
a
place
of
lower
potential,
and
consequently
the
ink
tends
to
flow
downwards
to
the
writing-tablet.
The
only
avenue
of
escape
for
it
is
by
the
fine
glass
siphon,
and
through
this
it
rushes
accordingly
and
discharges
itself
in
a
rain
upon
the
paper.
The
natural
repulsion
between
its
like
electrified
particles
causes
the
shower
to
issue
in
spray.
As
the
paper
moves
over
the
pulleys
a
delicate
hair
line
is
marked,
straight
when
the
siphon
is
stationary,
but
curved
when
the
siphon
is
pulled
from
side
to
side
by
the
oscillations
of
the
signal
coil.
It
is
to
the
mouse-mill
that
me
must
look
both
for
the
electricity
which
is
used
to
electrify
the
ink
and
for
the
motive
power
which
drives
the
paper.
This
unique
and
interesting
little
motor
owes
its
somewhat
epigrammatic
title
to
the
resemblance
of
the
drum
to
one
of
those
sparred
wheels
turned
by
white
mice,
and
to
the
amusing
fact
of
its
capacity
for
performing
work
having
been
originally
computed
in
terms
of
a
'mouse-power.'
The
mill
is
turned
by
a
stream
of
electricity
flowing
from
the
battery
above
described,
and
is,
in
fact,
an
electro-magnetic
engine
worked
by
the
current.
The
alphabet
of
signals
employed
is
the
'Morse
code,'
so
generally
in
vogue
throughout
the
world.
In
the
Morse
code
the
letters
of
the
alphabet
are
represented
by
combinations
of
two
distinct
elementary
signals,
technically
called
'dots'
and
'dashes,'
from
the
fact
that
the
Morse
recorder
actually
marks
the
message
in
long
and
short
lines,
or
dots
and
dashes.
In
the
siphon
recorder
script
dots
and
dashes
are
represented
by
curves
of
opposite
flexure.
The
condensers
are
merely
used
to
sharpen
the
action
of
the
current,
and
render
the
signals
more
concise
and
distinct
on
long
cables.
On
short
cables,
say
under
three
hundred
miles
long,
they
are
rarely,
if
ever,
used.
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