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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 is accidentally synthesized in 1872 by German chemist Eugen Baumann ...
The first plastic made from synthetic components, it was developed by Leo Baekeland in Yonkers, New York, in 1907, and patented on December 7, 1909. [ 3 ] Bakelite was one of the first plastic-like materials to be introduced into the modern world and was popular because it could be moulded and then hardened into any shape.
Notable early examples of coins include the Lydian Lion coins, Persian daric and siglos, Tong Bei, the dirham and gold dinar. Coins are a major archaeological source of history. Coins convey information about language, administration, religion, economic conditions, and the ruler who minted those coins. [1] Coins were first made of scraps of ...
Many coins throughout history were made of gold, silver and copper. Silver: Gold: Iron: Numerous Chinese cash coins were made of iron, with the first being issued by the Han dynasty in 118 BCE. From 1942 through 1952, some of the Swedish krona coins – such as the 1, 2 and 5 öre – were made of iron. Lead: Most commonly seen in southeast ...
The name is mostly applied informally to compositions between 20–80% gold and 80–20% silver, but these are strictly called gold or silver depending on the dominant element. Analysis of the composition of electrum in ancient Greek coinage dating from about 600 BC shows that the gold content was about 55.5% in the coinage issued by Phocaea .
Croesus replaced all the electrum coins by gold and silver coins using a single coin type: the facing foreparts of a lion and a bull. [1] Compared to later copies made by the Achaemenids, the original Croeseid use a more natural rendering of the two animals. [1] The reverse was struck with two incuse squares. [1] The coins were minted in Sardis ...
In the early 17th century Sweden lacked precious metals, and so produced "plate money": large slabs of copper 50 cm or more in length and width, stamped with indications of their value. Gold coins began to be minted again in Europe in the 13th century. Frederick II is credited with having reintroduced gold coins during the Crusades. During the ...
[16] [17] The gold objects unearthed included some 25 gold hoofs (a type of sycee) with varying weights from 40 to 250 grams and 50 very large gold coins weighing about 250 grams each. [14] [15] The gold coinages were packed inside of three different boxes that were placed under a bed that was located inside of the main chamber of the tomb.