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. CXCI. A Red Paint for Enamel.

THere can nothing exceed the Perfection of our Enamels of this Colour, taught in eight several Chapters of the Sixth Book; the like may be said of our Blood-colour, Rubies, Rose and Carbuncle, which is the most exalted Ingredient for Enameling Metal, or making Paint on Enamel; and those who practise this fine Art, use no other than that of the Glass-house, or such as they make accordingly. Now this Red Enamel is prepared as the other Colours with Aqua∣fortis to purifie it, wash'd, dry'd, and ground with Oyl of Spike for your use.

There is yet another tolerable Red, which they Paint with on Enamel, in which is employed calcined Gold; but this would be much more improved, if instead of their Rocaille they made use of our Matter made of Crystal and Saturnus Glorificatus in Chap. 113. or of our principal prepared Powder prescribed all along the Sixth Book, for these are exceeding well pu∣rified, whereas the Rocaille has too great a Surcharge of Lead, the Impurity whereof always renders the Work defective.

See here their way of calcining Gold, which is not near so fine as that we have given Chap. 115. and as there are an hundred several ways, so every Man makes use of his own as most excellent, and thinks it better than another's.

One takes an Ounce of fine Gold in very thin Plates, these dissolved in eight Ounces of Aqua-fortis, and regulated with Sal-Armoniack, or old strong Salt, in a small Glass Matrass, this is put into a Glass-Cu∣curbit,

wherein was already pour'd eight Paris Pints of Spring-Water, and six Ounces of Mercury, the Cucurbit is placed on a still Fire, and after four and twenty Hours the Gold descends to the bottom in a light Land-red Powder, then the Water is poured off leisurely into an earthen glazed Receiver, or Pan, and the Powder gathered and dryed by a moderate heat, and with a Shamois Skin they separate the Mer∣cury from the Gold, and grind this Powder with twice its weight of Flowers of Sulphur together, and then put all into a Crucible over a small Fire, where the Sulphur will communicate it self with the rest, and then evaporating they find the Powder somewhat ruddy, which ground with Rocaille, is what they make use of on the Enamel.

We own this Calcination to be tolerable as to the Gold, but as for mixing the Calx with the Rocaille, without melting them together to incorporate is dis∣putable: We believe that in grinding them together with Oyl of Spike, they may in some sort incorporate as other Colours, but can never so perfectly unite; besides, the Crystal Matter does not so well receive the Colour of the Gold this way, as if it were done by fusion.

Others make Red inclining to Vermilion, which they use in Painting after this manner. Take Vitriol calcined in two Crucibles well luted together, and set for an Hour over a flow Fire; then purge it with Aqua-fortis, wash it in fair Water, and grind it with Oyl of Spike as before, and so make use of it for Ena∣mel.

All Red Enamel which is good, ought to be hard, and not easily consumed in the Fire; for that which is otherwise, contains much Lead, and soon becomes dull and sullied, and is not of so lasting a substance, which the Workmen ought to be cautious of.

To finish the Preparation of Enamel, and before the manner of painting 'em is prescribed, take no∣tice, that all the Colours before mentioned, which are not pure Enamel, ought to be incorporated with a Crystalline Matter, such as we prescribed in Chap. 148. to the end they may vitrifie the better, which else they'll not easily do, the most Workmen make use of their Rocaille, whether to avoid the trouble of making (or that they are ignorant how to prepare) a better Matter; and this has obliged us to give seve∣ral ways very good and true for their purpose to make fine and perfect Work by.