DOC.
14
PROOF OF
AMPERE'S CURRENTS
179
702
phase
of
the oscillations
of
the
cylinder
is behind
that of
the current
by an
amount
v
x/2;
this
follows from
(9)
and
(13). Remembering
further that
in
the deduction of
(11)
it has been assumed
that
the
circulating
electrons
are negative
and that
if
they
were positive
ones,
the
sign
of
B1
and the
phase
of
the effect
would
be
reversed
we are
led to
the
following
conclusion:
Negative
electrons.
ww0.
The
phase
of
the oscillations
of
the
cylinder
is
a
quarter
of
a period
behind
that of
the current.
ww0.
It
is
a
quarter
of
a period
in advance.
w=w0.
The
vibration has
the
same phase as
the
current.
Positive electrons.
ww0.
The
phase
of the oscillations
of the
cylinder
is
a
quarter
of
a period
in advance of that of
the current.
ww0.
It is
a
quarter
of
a
period
behind that of the
current.
w=wo.
The
vibration of
the
cylinder
and
the
current
have
opposite
phases.
It
is important
to notice that there
is
a
quarter
of
a period
difference
of
phase
between
the
active
couple
B1
cos
wt and the
current
i
=
A
sin
wt
and
likewise between
the
active
couple
and
the
alternating magnetisation.
This
is
always so,
independently
of
the
relative values of
w
and
w0
and of
the
sign
of the
circulating
electrons.
$
4.
Short
description
of
the
apparatus.
[10]
The
alternating
field which
has
been
mentioned several times
already
was
excited
by
two coils
placed
with their
axes along
the
same
vertical line and with
a
distance of
about
1
cm
between
them.
They were
mounted
on
a
brass
foot to
which
three
foot
screws
could
give
different inclinations. The
coils
were
connected in
series
and
gave a
field
of about 50
Gauss. The
iron
cylinder
was suspended
along
their
axis.
This
cylinder,
1.7
mm
thick
and in
the
first
experiments
7
cm
long, was
carefully
turned of
soft
iron.
Centrally
in its
top
there
was
bored
a narrow
hole of diameter 0.3
mm
in
which
a fitting glass
wire
was
sealed.
At
its middle the
cylinder