The
logic
of
the
scientific
method
was
set
out
by
John
Stuart
Mill
in
1843
,
and
____________________
named
the
method
of
difference
.
A
simple
example
of
what
he
meant
by
this
is
to
take
two
____________________
of
water
which
are
____________________
in
every
respect
.
Introduce
a
few
drops
of
ink
into
one
of
these
glasses
.
The
water
____________________
colour
!
According
to
Mill's
method
of
difference
it
is
safe
to
assume
that
the
change
in
the
colour
of
the
water
is
due
to
the
____________________
of
a
new
factor
-
the
independent
variable
-
in
this
case
,
the
ink
.
