will be found sufficient to mix a little gold-size with lamp-black;
this will bear a good gloss, without requiring to be varnished
afterwards.


190. TO PREPARE A FINE TORTOISE-SHELL JAPAN

Take 1 gallon of good linseed oil, and 1/2 lb. of umber; boil them
together till the oil becomes very brown and thick, then strain it
through a coarse cloth, and set it again to boil; in which state it
must be continued till it acquires a consistence resembling that of
pitch; it will then be fit for use.


191. DIRECTIONS FOR USING TORTOISE-SHELL JAPAN

Having thus prepared the varnish or japan, clean well the substance
which is to be japanned; then lay vermillion, tempered with
shell-lac varnish, or with drying oil, very thinly diluted with
oil of turpentine, on the places intended to imitate the more
transparent parts of the tortoise-shell; when the vermillion is
dry, brush the whole over with black varnish, tempered to a due
consistence with the oil of turpentine. When set and firm, put the
work into a stove, where it may undergo a very strong heat, which
must be continued a considerable time; if even three weeks or a
month it will be the better. This tortoise-shell ground it not less
valuable for its great hardness, and enduring to be made hotter
than boiling water without damage, than for the superior beauty and
brilliancy of its appearance.