Search results
Results from the WOW.Com Content Network
Parkesine, the first member of the Celluloid class of compounds and considered the first man-made plastic, is patented by Alexander Parkes. [4] 1869: John Wesley Hyatt discovers a method to simplify the production of celluloid, making industrial production possible. 1872: PVC was accidentally synthesized in 1872 by German chemist Eugen Baumann ...
The manufacture of true ormolu employs a process known as mercury-gilding or fire-gilding, in which a solution of mercuric nitrate is applied to a piece of copper, brass, or bronze; followed by the application of an amalgam of gold and mercury. The item is then exposed to extreme heat until the mercury vaporizes and the gold remains, adhering ...
Celluloids are a class of materials produced by mixing nitrocellulose and camphor, often with added dyes and other agents.Once much more common for its use as photographic film before the advent of safer methods, celluloid's common present-day uses are for manufacturing table tennis balls, musical instruments, combs, office equipment, fountain pen bodies, and guitar picks.
Other terms often used for printed engravings are copper engraving, copper-plate engraving or line engraving. Steel engraving is the same technique, on steel or steel-faced plates, and was mostly used for banknotes, illustrations for books, magazines and reproductive prints, letterheads and similar uses from about 1790 to the early 20th century, when the technique became less popular, except ...
Crystalate is an early plastic. [78] Faturan is a phenolic resin, also similar to Bakelite, that turns red over time, regardless of its original color. [79] Galalith is an early plastic derived from milk products. [80] Micarta is an early composite insulating plate that used
The model 302 telephone is a desk set telephone that was manufactured in the United States by Western Electric from 1937 until 1955, and by Northern Electric in Canada until the late 1950s, until well after the introduction of the 500-type telephone in 1949. The sets were routinely refurbished into the 1960s.
The earliest gold artifacts were discovered at the site of Wadi Qana in the Levant. [13] Silver is estimated to have been discovered in Asia Minor shortly after copper and gold. [14] There is evidence that iron was known from before 5000 BC. [15] The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in ...
Tumbaga is the name given by Spanish Conquistadors for a non-specific alloy of gold and copper, and metals composed of these elements. Pieces made of tumbaga were widely found in pre-Columbian Mesoamerica in North America and South America. The term is a borrowing from the Tagalog tumbaga. This came from Malay tembaga, meaning 'copper' or ...