CHAP. LXXXVII. To make a Sky, or Sea-Green, in Glass of Lead.
WE have shewn several Ways in the first Book to tinge Glass of a Sky-colour, or Sea-Green, which would be needless to repeat here.
That we now shew which is made in Glass of Lead, has no less Beauty. Take sixteen Pound of Crystal Fritt, ten Pound of Calx of Lead, mix them toge∣ther, and put them gently into a Pot heated in the Furnace, where they will be in good fusion in twelve Hours time. Then cast that Matter into Water, as I have shewn before, and take the remaining Lead out of the Pot, and put yout Matter in again to melt. Eight Hours after cast it again into Water, taking the remaining Lead out of the Pot, then it will be well purified. Put it in again to melt in the same Pot, and when it is in good fusion, cast in at four dif∣ferent times, four Ounces of small Copper Leaves, prepared as in Chap. 30, with a quarter of an Ounce of Zaffer, prepared as in Chap. 17. After having mixed these Powders well together, and the Matter at each casting of it in: Two Hours after stir the Matter well in the Pot with an Iron Rod, and make an Essay to see if the Colour be full enough, then let it stand ten Hours to purifie, and to give the Colour time to incorporate with the Glass: Then it may be wrought to the Uses you design it, stirring