Quantcast
  Due to a new server, slow response may occur for which we apologize Portal logo
Login/Register
Bactrian Gold Treasure from Afghanistan, coming soon....
/gemstones/agricola_textbook_of_mineralogy/page_201 - 2
 

Book IX artificially coloring of metals such as gold, silver, copper

Book IX artificially coloring of metals such as gold, silver, copper Page of 251 Book IX artificially coloring of metals such as gold, silver, copper Text size:minus plus Restore normal size   Mail page  Print this page
BOOK IX
189
lar leaves three-quarters of an inch wide are made from the thick gold plated sheets. These leaves are fastened to bands and worn around the head by young girls. Thin sheets are not used in the third method of plat­ing silver. Quicksilver is used and although the method was known to Pliny he did not describe it. Today the following method is used. An eighth of an ounce of gold that is quite pure or contains only a very small amount of silver is beaten out into a thin foil three inches long and two inches wide. After the foil is cut into small pieces and placed in a crucible three-quarters of an ounce of quicksilver is added. The mixture is poured into another crucible lined with chalk and then heated over a charcoal fire. It is placed in the fire with a pair of tongs and left until all the gold has been dissolved in the quicksilver and no flash of gold can be observed. When finished the quicksilver is poured into the shell of a marine scallop that has been filled with water. After it has cooled the water is poured off and the quicksilver left in small particles similar to wheat meal and can be picked up with the fingers. This is then spread over the silver object that is to be plated using an iron instrument. Before applying the quicksilver, the silver object is heated in a charcoal fire and quenched in water in which argol and salt have been boiled in order to make it white. After this it is cleaned by brush­ing with brass wires that have been bound together, although it has al­ready been cleaned by quenching. After the quicksilver has been applied the object is exposed to the fire a second time so that it will take the mix­ture. During the heating the mixture is spread evenly by brushing it with pig bristles that have been bound together. Eventually the quick­silver is driven off by the heat of the fire and the gold remains. If any part has not received sufficient gold more quicksilver can be added to the area and it is heated and brushed a second time.
Copper and brass can be gold plated in a similar manner. Iron and the steel the Greeks call στόμωμα, as I have said, is first polished and then smeared with wine in which has been boiled one part of argol, one-half part artificial sal ammoniac, one half part verdigris and a little salt. Usually it is brushed with pig bristles that have been dipped in the wine. After drying it is plated with the same mixture of gold and quicksilver, using the same method as that for copper and silver. Enough concerning gold plating.
Copper and brass are silver plated in the following manner. Argol, alum, and salt are first ground to a powder. Then thin silver foil is ground on flint with this powder and the mixture placed in a jar that has been coated with litharge or molten lead. After water is added the article to be plated is placed in the mixture and the jar warmed. After warming for some time the article is removed and brushed with pig bristles to determine if it is plated satisfactorily.
One metal is coated with another metal in the following manner. Cop­per, brass or iron that is to be coated with silver, stannum, stannum argentarium, or tin, is first rubbed with vinegar in which artificial sal
Book IX artificially coloring of metals such as gold, silver, copper Page of 251 Book IX artificially coloring of metals such as gold, silver, copper
Suggested Illustrations
Other Chapters you may find useful
Other Books on this topic
bullet Tag
This Page