purity of other pigments is in question, should be itself white, while
the browner sorts of polishing dust, as being cheaper and doing their
business with greater dispatch, may be used in other cases. The pieces
of work to be varnished should be placed near the fire or in a warm
room and made perfectly dry, and then the varnish may be applied with
a flat camel-hair brush made for the purpose. This must be done very
rapidly, but with great care; the same place should not be passed
twice over in laying on one coat if it can possibly be avoided. The
best way of proceeding is to begin in the middle and pass the brush to
one end, then with another stroke from the middle pass it to the other
end, taking care that before each stroke the brush be well supplied
with varnish; when one coat is dry another must be laid over it in
like manner, and this must be continued five or six times. If on trial
there be not a sufficient thickness of varnish to bear the polish
without laying bare the painting or ground colour underneath more
varnish must be applied. When a sufficient number of coats of varnish
is so applied the work is fit to be polished, which must be done in
common work by rubbing it with a piece of cloth or felt dipped in
tripoli or finely ground pumice-stone. But towards the end of the
rubbing a little oil of any kind must be used with the powder, and
when the work appears sufficiently bright and glossy it should be
well rubbed with the oil alone to clean it from the powder and to give
it a still greater lustre. In the case of white grounds, instead of
the tripoli, fine putty or whiting should be used, but they should be
washed over to prevent the danger of damaging the work from any sand
or any other gritty matter that may happen to be mixed with them. It
greatly improves all kinds of japan work to harden the varnish by
means of heat, which, in every degree that can be applied short of
what would burn or calcine the matter, tends to give it a firm and
strong texture where metals form the body; therefore a very hot stove