The plates of copper often heated, are to be quenched in cold water of which more in the Fifth part, from three to six grains of it may be mixed with ℥ j. of the mass for a Sea-green colour. Iron is reduced into crocus by reverberation; of which from four to ten grains are added to the mass for a yellow or Jacynth colour; Silver is dissolved in _Aqua fortis_, and precipitated with the liquor of Flints after it is edulcorated and dryed, whereof from one to six grains, added to ℥ j. of the mass, they make mixt colours. Gold is dissolved in _Aqua Regia_, edulcorated and dryed, precipitated first with liquor of Flints, whereof from grain four to ℈ _ss._ mixt with one ounce of the mass, make a most elegant Saphire. And if from three to six of that soluble ruby made of the Gold, and the nitrous _Regulus Martis_ be added to ℥ j. of the mass, they make a very polite ruby: Magnesia pulverised, whereof, from six to fourteen grains, to ℥ j. of the mass, make an Amethyst. Marcasit dissolved in _Aqua Regia_, precipitated with the liquor of flints, edulcorated and dryed, whereof from one to five grains, to ℥ j. of the mass, give a Saphire, but not comparably so polite as one made with gold. But being unwilling to calcine Marcasite, let him take Zafora, and mingle to ℥ j. from five to ten grains; Granates of _Bohemia_, or Oriental pulverised, add from six grains to ℈ j. to ʒ j. of the mass, for little green stones like to the natural smaragd or emrald: other things which remain of the mixture of the colours, are to be learned by experience.