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. XXVII. Another way of making Crocus Martis with Aqua Regalis.

THis is a fourth way of making Crocus Martis, and perhaps the best of all, because in them you cannot find such Diversities of Colours as in this.

Dissolve, silings of Iron or Steel, in a Glass Body well Covered, in Aqua Regalis, that is in Aqua Fortis made Aqua Regalis with sal Armoniac, as we shall shew in the second Book. Keep them so three days, stir∣ring them every day well, during which you may add fresh filings little by little, wherein you must be very Cautious: for it riseth so much by Fermentati∣on

in the Aqu. Reg. that it will endanger breaking the Glass or running over. After three days set your Cucurbite on a gentle Fire, that all the Water may Evaporate till it leaves the Crocus behind dry, which is admirable for Tinging Glass, which keep for use.