Seller: jazb03 (371) 100%, Location: Iowa City, Iowa, Ships to: US & many other countries, Item: 331835129227 Color: Silver, Material: Mercury glass, Details: PLEASE READ DESCRIPTION: These came out of the house they were put in new when it was built in 1896. These were made by hand. there were major variations in some which is what lead me to pair them as that is how they would have been used. I used callipars to guage the throat and height as closely as could be. From the research I did and looking at others there is no such thing as identical as they were hand made. which is why they are listed as a pair not as identical. the hand etchings are not identical, that is the beauty of historical craftsmanship. These Grape Vine and Grape Cluster etched pair of curtain tie backs. They are made of mercury glass with pewter backs. They were likely made by the New England Glass Company or Boston Sandwich Glass Company. They are a matched pair. 3 inch by 3 1/4 inches. Width of throat about 1 1/4 inch. There is some aging and slight variations in size. Mercury glass (or silvered glass) is glass that was blown double walled, then silvered between the layers with a liquid silvering solution, and sealed. Although mercury was originally used to provide the reflective coating for mirrors, elemental mercury was never used to create tableware. Silvered glass was free-blown, then silvered with a solution containing silver nitrate and grape sugar in solution, heated, then closed. Sealing methods include metal discs covered with a glass round or a cork inserted into the unpolished pontil scar. "Mercury" silvered glass was produced originally from around 1840 until at least 1930 in Bohemia (now the Czech Republic), Germany and also manufactured in England from 1849 to 1855. Edward Varnish and Frederick Hale Thomson patented the technique for silvering glass vessels in 1849. The English examples were often cased with a layer of colored glass then cut to silver as illustrated in the photograph. Companies in the United States, including the Boston and Sandwich Glass Company, New England Glass Company, Union Glass Co., and the Boston Silver Glass Company, made silvered glass from about 1852–1880. The New England Glass Company displayed a variety of silvered glass articles including copper wheel engraved goblets, vases and other tableware at the 1853 New Crystal Palace Exhibition.