55 / 230
CONTINUOUS
DISTILLATION.
Fig.
8.
55
Fig.
9.
number
of the
plaits,
between
each
of
which
(as
in
^g.
8)
a
ledge
is
run
from
side
to
side
of
the
still,
and
fastened
to
both,
leaving
a
passage
the
whole
length
underneath,
be-
tween
its
lower
edge
and
the
bottom
of
the
groove
formed
by
the
plait,
by
which
the
liquid
in
its
whole
course
is
re-
duced
to
a
stratum
of
any
thickness
required
along
a
surface
of
immense
extent,
occupying
comparatively
but
a
small
space,
and
exposed
to
all
the
heat
of
the
fire.
In
the
fore-
going
descriptions
the
stills
have
been
considered
as in
im-
mediate
contact
with
the
fire
;
but
it
is
proposed
to
work
them
by
steam,
which
may
be
applied
either
externally
or
internally,
or
both,
as
shown
in
fig.
10.
In
this
figure,
a
represents
a
steam-boiler,
furnished
with
safety-valves,
and
supplied
with
water
in
the
usual
way
:
this
boiler
is
surmounted
by
three
stills
upon
the
foregoing
principles.
The
bottoms
are
perforated
at
certain
distances
through-
out
their
whole
extent,
and
into
each
of
these
perforations
a
tube
is
inserted,
branching
into
ramifications
of
smaller