34. A Procedure for Writing in Letters of Gold.
To
write in letters of gold, take some mercury, pour it in a suitable
vessel, and add to it some gold in leaves; when the gold appears
dissolved in the mercury, agitate sharply; add a little gum, 1 grain
for example, and, (after) letting stand, write in the letters of gold.
35. Another (Recipe).
Golden-colored litharge, 1 part; alum, 2 parts.
36. Manufacture of Asem that is Black like Obsidian.
Asem,
2 parts, lead, 4 parts. Place in an earthen vessel, throw on it a
triple weight of unburnt sulfur, and having placed it in the furnace,
melt. A nd having withdrawn it from the furnace, beat, and make what
you wish. If you wish to make figured objects in beaten or cast metal,
then polish and cut. It will not rust.
37. Manufacture of Asem.
Good
tin, 1 part; add to it, dry pitch, one quarter of the weight of the
tin; having stirred, let the pitch froth until it has been completely
ejected; then, having let the tin solidify, remelt it and add 13
drachmas of tin (and) 1 drachma of mercury, (then) stir up; let cool
and work just like asem.
38. For Giving to Objects of Copper the Appearance of Gold.
And
neither touch nor rubbing against the touchstone will detect them, but
they can serve especially for (the manufacture of) a ring of fine
appearance. Here is the preparation for this. Gold and lead are ground
to a fine powder like flour, 2 parts of lead for 1 of gold, then having
mixed, they are incorporated with gum, and one coats the ring with this
mixture; then it is heated. One repeats this several times until the
object has taken the color. It is difficult to detect (the fraud),
because rubbing gives the mark of a gold obiect, and the heat consumes
the lead but not the gold.
39. Writing in Letters of Gold.
Letters of gold: saffron (and) bile of a river tortoise.
40. Manufacture of Asem.
Take
white tin, finely divided, (and) purify it four times; then lake 4
parts of it, and a fourth part of pure white copper and 1 part of asem
(and) melt: when the mixture has been melted sprinkle it with the
greatest possible quantity of salt, and make what you wish with it,
either by hammering or by any way you please. The metal will be equal
to true asem, so much so as to deceive even the artisans.
41. Another (procedure).
Silver,
2 parts; purified tin, 3 parts; copper (?) drachmas; melt, then remove
and clean; put in use for works of silver of the best kind.
42. Coating of Copper.
If
you desire that the copper shall have the appearance of silver; after
having purified the copper with care, place it in mercury and white
lead; mercury alone suffices for coating it.
43. Testing of Gold.
If
you wish to test the purity of gold, remelt it and heat it: if it is
pure it will keep its color after heating and remain like a piece of
money. If it becomes white, it contains silver; if it becomes rougher
and harder some copper and tin; if it blackens and softens, lead.
