Chapter XXXV How to Make Aquafortis for Parting
Aquafortis for parting198 is made thus. You take 8 lbs. of burnt rock alum199 & an equal quantity of the best saltpetre, and 4 lbs. of Roman vitriol, & put them altogether into the alembic,200 add to these things a little aquafortis that has already been used, exercising your discretion as to the quantity. And in order to give a good luting201 to your alembic take horse-dung, iron filings & brick dust in equal proportions, and mix them up with the yolk of a hen’s egg, then smear the mixture over the alembic as far as the furnace will allow. Then for the rest put it to a moderate fire, as the wont is.
Footnotes
198 Partire.
199 Allume di rôcca arso. Prof. Church tells me that this is probably sulphate of alumina, from alum shale.
200 Boccia. Biringoccio in the fourth book of his ‘Pirotechnica,’ Venice, 1540, Chap. I., gives an illustrated description both of such an alembic and of how aquafortis for parting is distilled. See also the French edition of the same book translated by ‘Jaques Vincent.’ Rouen, 1627.
201 Loto: the closing of the joints.