History
The commonly known Dutch method for the preparation of cerussa was described as early as Theophrastus of Eresos (ca. 300 B.C.), in his brief work on rocks or minerals, On Stones or History of Stones. His directions for the process were repeated throughout history by many authors of chemical and alchemical literature. The uses of cerussa were described as an external medication and as a pigment.
Clifford Dyer Holley quotes from Theophrastus' History of Stones as follows, in his book The Lead and Zinc Pigments.
Lead is placed in earthen vessels over sharp vinegar, and after it has acquired some thickness of a sort of rust, which it commonly does in about ten days, they open the vessels and scrape it off, as it were, in a sort of foulness; they then place the lead over vinegar again, repeating over and over again the same method of scraping it till it has wholly dissolved. What has been scraped off they then beat to powder and boil for a long time, and what at last subsides to the bottom of the vessel is ceruse.
Later descriptions of the Dutch process involved casting metallic lead as thin buckles and corroded with acetic acid in the presence of carbon dioxide. This was done by placing them over pots with a little vinegar (which contains acetic acid). These were stacked up and covered with a mixture of decaying dung and spent tanner's bark, which supplied the CO2, and left for six to fourteen weeks, by which time the blue-grey lead had corroded to white lead. The pots were then taken to a separating table where scraping and pounding removed the white lead from the buckles. The powder was then dried and packed for shipment or shipped as a paste. One benefit of the process was that it was not necessary to dry the paste of white lead, removing its water. All that needed was to mill the paste with linseed oil, and the white lead would take up the oil and reject the residual water, to give white lead in oil.
Read more about this topic: White Lead
Famous quotes containing the word history:
“Literary works cannot be taken over like factories, or literary forms of expression like industrial methods. Realist writing, of which history offers many widely varying examples, is likewise conditioned by the question of how, when and for what class it is made use of.”
—Bertolt Brecht (1898–1956)
“In history as in human life, regret does not bring back a lost moment and a thousand years will not recover something lost in a single hour.”
—Stefan Zweig (18811942)
“The history of literature—take the net result of Tiraboshi, Warton, or Schlegel,—is a sum of a very few ideas, and of very few original tales,—all the rest being variation of these.”
—Ralph Waldo Emerson (1803–1882)