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. XXVIII. Another way to make Crocus Martis.

THis way tho' it be easy makes a Crocus of no less Virtue and Beauty than the precedent. To make it take fine filings of Iron or Steel without any rust, let them stand in a Reverberatory Furnace with a very strong Fire, the heat being at least to the fourth degree, till it becomes of the Colour of Pur∣ple. Then take it out of the Fire, and when it is Cool, put it into a Vessel full of Water, and stir it briskly about, and then presently pour off the Water into another Vessel, which you may reiterate. Thus there will remain in the first Vessel the Iron that is not yet Calcined, which if you please you may put a∣gain into a Reverberatory Furnace; In the second Vessel there will be the Crocus which set over a gentle Fire to evaporate the Water. But you must not de∣cant off the Water tho' it appears clear after it has settl'd: for tho' the Crocus may seem to be precipi∣tated to the bottom, yet the Water Contains the most subtile parts of it imperceptibly suspended in it. Having well Evaporated the Water you will have a very red Powder, very fine and Extraordinary, which keep for use.