Valuable Secrets concerning Arts and Trades:
or Approved Directions, from the best Artists, for the Various Methods...
Printed by Thomas Hubbard,
Norwich, 1795Chap. III. Secrets for the composition of Varnishes, &c.
I. A gold varnish.
Take karabe or amber, eight ounces, and two of gum-lac. Melt first the karabe, in a varnished earthen pot, or in the retort of an alembic, over a very strong fire. When this is melted, throw in the gum-lac, and let this melt in the same manner. Then take some of the fire off, and let it cool: observing with it stick, whether the matter has got all its fluidity. Mix in it fix, or eight, ounces of turpentine oil. Keep stirring, with a stick, in order to incorporate well this oil with the rest. Add also a spoonful of lintseed oil, prepared with hepatica-aloes, to the considence of a balm; which, in order to thin, and reduce it to the thickness of a syrup, you mix with a sufficient quantity of oil of turpentine, tinged with rocou.
II. How to prepare the lintseed oil with the hepatica-aloes, for the above purpose.
You prepare the lintseed oil with hepatica-aloes, by mixing four ounces of this in powder, with one pound of the said oil, which you do over the fire, till it has acquired the consistence of a very thick syrup, and you see your oil beginning to scum, and to swell much. - Then pass it through a piece of linen, let it cool, and bottle it, to keep for the above-mentioned use.
III. How to draw the tincture of rocou used in the composition of the above varnish.
In order to draw the tincture of rocou, put four ounces of it in oil of turpentine. Set this over a gentle fire, in the retort of an alembic; and, as soon as the oil begins to boil, take it off from the fire: stir well with a stick, and filter it through a paper, to use it as directed before.
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