130 - The Way to Fix Sulfur for Rosichiero to Enamel Gold
Make a strong head [of foam] from [a solution of] lime and strong oak firewood ash. In this lime, boil sulfur vigorously. This leaves the lye a definite unctuous color, and combustible, due to the sulfur changing in the lye. The sulfur becomes white, and incombustible. Now thoroughly fixed, use it to make rosichiero for the goldsmiths to enamel over gold.