The manufactures comprise steel goods, mustard and vinegar, and a special kind of white lead (Kremser Weiss) is prepared from deposits in the neighbourhood.
Pliny mentions it under the name of minium, but it was confused with cinnabar and the red arsenic sulphide; Dioscorides mentions its preparation from white lead or lead carbonate.
By the action of the acetic acid and atmospheric oxygen, the lead is converted superficially into a basic acetate, which is at once decomposed by the carbon dioxide, with formation of white lead and acetic acid, which latter then acts de novo.
C. t has for its subject pavements and roads, their construction, mosaic floors; c. 2 is on white stucco for walls (opus albarium); c. 3 on concrete vaults, gypsum mouldings, stucco prepared for painting; c. 4 on building of hollow walls to keep out the damp, wall decoration by various processes; c. 5 on methods and styles of wall painting, the debased taste of his time; c. 6 on fine stucco made of pounded marble - three coats to receive wall paintings; c. 7 on colours used for mural decoration; c. 8 on red lead (minium) and mercury, and how to use the latter to extract the gold from wornout pieces of stuff or embroidery; c. 9 on the preparation of red lead and the method of encaustic painting with hot wax, finished by friction; cc. to-14 on artificial colours - black, blue, purple;, c. to white lead and ostrum, i.e.
As long as the solution contains lead, the addition of the molybdate solution causes a precipitation of white lead molybdate.
In regard to the ancients' knowledge of lead compounds, we may state that the substance described by Dioscorides as, uoXv,3Saiva was undoubtedly litharge, that Pliny uses the word minium in its present sense of red lead, ana that white lead was well known to Geber in the 8th century.
Venetian white, Hamburg white and Dutch white are mixtures of one part of white lead with one, two and three parts of barium sulphate respectively.
Any residue consists of black mercuric sulphide (and possibly white lead sulphate), in which mercury is confirmed by its usual tests.
There are numerous saw-mills, shipbuilding yards, engineering works, distilleries, sugar refineries, tobacco factories, linen bleacheries and stained glass, salt and white lead works.
These are knocked off, ground up with water, freed from metal-particles by elutriation, and the paste of white lead is allowed to set and dry in small conical forms. The German method differs from the Dutch inasmuch as the lead is suspended in a large chamber heated by ordinary means, and there exposed to the simultaneous action of vapour of aqueous acetic acid and of carbon dioxide.