Lixivial

[…] we obtain'd, more than once, out of 16 ounces of salt-petre, 10 ounces of fix'd nitre, very lixivial in tast and operation, and of a pleasant greenish blue colour, deeper than salt of tartar will usually be brought to, by being, in a crucible, kept twenty times as long in a strong fire.

But such may rest satisfied that those dextrous and conscientious Artificers the Chymists, can furnish us with a Lixival Salt of any Plant we want, made from the Cineres Clavellati or Pot-Ashes.