116 / 330
116
600
MISCELLANEOUS
VALUABLE
RECEIPTS.
is
better
adapted
for
distemper.
Its
colour
may
be
obtained
in
oil
by
mixing two
or
three
parts
of
ver-
digris
witli
one
of
white
lead.
Green
Lake^
or
Venetian
Emerald.
—
A
very
simple
mode
has
recently
been
discovered,
at
Venice,
of
pro-
ducing
a
fine
unchangeable
emerald
colour.
A
quan-
tity
of
coffee
is
boiled
in
river-water,
—
if
spoiled
cof-
fee,
so
much
the
better.
The
green
lake
obtained
by
this
process
is
said
to
have
resisted
the
action
of
acids,
and
even
the
infi.uence
of
light
and
moisture.
Browns.
—
Umber,
or,
as
it is
sometimes
called,
brown
ochre,
is
an
impure
native
oxide
of
iron
and
manganese.
It
is
much
employed
by
painters,
and
is
the
only
simple
brown
in
common
use.
JVew
Brown,
discovered
by
Mr.
Hatchet.
This
celebrated
chemist
has
suggested
to
painters
that
a
simple
brown
colour,
far
superior
in
beauty
and
intensity
to
all
the
browns,
whether
simple
or
com-
pound,
hitherto
known,
may
be
obtained
from
the
prussiate
of
copper,
(a
combination
of
prussic
acid
with
copper.)
The
following
is
the
process
which
he
recommends
:
Dissolve
the
green
muriate
of
copper
in
about
ten
times
its
weight
of
distilled
or
rain
water,
and
add
a
solution
of
prussiate
of
lime,
until
a
complete
pre-
cipitation
is
effected.
The
precipitate
is
then
to
be
washed
with
cold
water,
filtered,
and
set
to
dry
in
the
shade.
No.
227.
Of
different
Oils
used
in
Painting
and
Varnishing.
Oil
of
Spike
is,
if
pure,
a
volatile
oil,
and
has
the
advantage
of
drying
more
quickly
than
any
other
fat-oil.