25. Of the blue Paint called Smalt, by means of Salt of Tartar may a most excellent Paint be made for Limners, not inferiour to Ultramarine.
26. Of Mercury, Jupiter, Sulphur and Sal. Armoniack is made the Paint called Aurum Musicum.
A Cementation that graduates Venus into Sol.
27. Recipe Vitriol calcined to Redness, mix it with Salt and Coal dust, lay this with thin Copper Plates stratum super stratum, put them into a Fire that may keep the Plates of Venus red hot for six hours without melting them, by which means the Sol in the Venus will be encreased; if we repeat this Cementation several times till the Venus be of a golden colour, the gain will be much greater. N. B. The cause of this melioration is, because the Coal Dust hinders the corrosive Spirits of the Vitriol and Salt from corroding the Venus, and therefore onely penetrates and graduates the same.
To make all Corrosives sweet.
28. Vitriol distilled with Salt yields a Corrosive Spirit, but if Coal Dust be mixed with them, they give a sweet Spirit, which graduates Lune into Sol when digested therein.
29. Recipe, Calx of Jupiter mixed with Mercury of Lune, and therewith Cement plates of Venus, by which means the saline Spirits introduce the white Sulphur of Jupiter into the Venus, and change it into Lune containing much Sol.
A sweet graduating Spirit, usefull to the Melioration of Metals.
30. Recipe, Coal Dust, mix them with Sal Mirabilis, and distill by retort, and you will get a sweet graduating Spirit, exalting some Metals to Sol.