Merret 1662

C[hristopher] M[erret], The Art of Glass, Wherein Are shown the wayes to make and colour Glass, Pastes, Enamels, Lakes, and other Curiosities. Written in Italian by Antonio Neri, and Translated into English, with some Observations on the Author. Whereunto is added an account of the Glass Drops, made by the Royal Society, meeting at Gresham College, London [A. W.] 1662.

The first Book.

. . .

p. 27

To prepare Zaffer which serves for many colours.
CHAP. XII.

TAke Zaffer in gross pieces, put it into earthen pans, let it stand half a day in the furnace, & then put it into an Iron ladle to be heated red hot in the furnace, take it thence thus hot and sprinkle it with strong vineger, as soon as ’tis cold grind it fine on a Porphyrie stone, wash it in earthen pans glased, with much warm water, always suffering the Zaffer to settle to the bottom, then decant it gently off; this will carry away the foulness and Terrestriety from the Zaffer, and what is good, and the tincture thereof will remain at the bottom, which thus prepared and purified will tinge much better than at first, making a limpid and clear tincture, which dry and keep in vessels closed for use.

Observations on the Author.

. . .

p. 320

Chap. 72.

BLew Smalts for Painters.

I cannot find the composition hereof in any writer, but I have been informed by an honest workman in Glass, that ’tis made of Zaffer, and Pot-ashes calcin’d together in a furnace, made like that for Glass, and that he wrought it in Germany. But of this, and all other natural and artificial colour in a treatise designed on this subject.

Gold hinders the rising of the Metall.

And so doth a little Oyl, or Tallow, thrown into a Copper of boyling Sugar, hinder it’s running over into the fire, though it rise with the greatest fury.