The art of glass shewing how to make all sorts of glass, crystal and enamel : likewise the making of pearls, precious stones, china and looking-glasses : to which is added, the method of painting on glass and enameling : also how to extract the colours from minerals, metals, herbs and flowers ... : illustrated with proper sculptures / written originally in French, by Mr. H. Blancourt, and now first translated into English ; with an appendix, containing exact instructions for making glass-eyes of all colours.

CHAP. XLIII. A fine Sky-Colour or Sea-Green in Crystal.

THis fine Colour requires a Crystal Fritt well purified from its Salt, as we have noted be∣fore; and which has not been put into Water. Put 60 Pounds in a Pot, and having well prepared it, put in one Pound and half of Scales of Copper in Powder, the Preparation whereof we have shewn in Chapter XXXIV. with four Ounces of Zaffer prepa∣red and mixed together; and stir the whole well with the Glass for the space of two hours. Then see whether you like the Colour, then let it stand

at rest 24 hours; then stir the whole again, as be∣fore, that it be well mixed with the Glass and the Colour incorporated with it; then it may be wrought. It will give a very fine Blue, as has been often experimented. The Colour may be heigh∣tened as you please; but take care you do not make it too high. If you mix with Fritt of Rochetta, as much Crystal Fritt, you'll have as fine a Blue as can be wished.