DOC. 124
OCTOBER
1908 89
I,
too,
invented
a
Maschinchen. It
is
like this:
An illustrated
example
will
give you
the
general
idea.
glass thread
glass tube
mirror
condenser
plate
mica or ebonite etc.
condenser
(ground)
cross-section
of the
condenser
plates
Hg
Since the
condenser
plates
are
exactly
below
one
another
in the
initial
position,
they
have
a
large
capacitance.-
With
the
Maschinchen
or
electrometer
totally
uncharged,
the
movable
part is
set into
oscillation
by means
of
an
external
cause.
Then
the
condenser's external
part,
which
is
driven
by
a
clockwork
or
something
on
that
order, is
adjusted
in such
a way
that
it
oscillates
exactly
as
rapidly
as
the
part suspended
from the
glass
thread.
Now
one
is
ready
for
the
test.
One
connects the movable
part
with the
test
voltage
(after
it has
come
to
rest,
of
course),
and
now one
lets the clock
run.
Since
the
change
in
the
capacitance
is
very
great
(movable
part
in the condenser, movable
part free),
the
force
producing
the deflection
is
great.
Since
even
the smallest
motion
is
amplified by
the
pendulum
mechanism and
shows
up
in
the
reading,
I believe
that
even
the
lowest
voltages can
be measured
with this
instrument. Of
course,
this
principle is not
restricted
to
electrostatic
things,
but
can
be
applied
in
many
other
measuring
instruments
as
well.