Watch Jewels
Jewel bearings were invented and introduced in watches by Nicolas Fatio (or Facio) de Duillier and Pierre and Jacob Debaufre around 1702 to reduce friction. They did not become widely used until the mid 19th century. Until the 20th century they were ground from tiny pieces of natural gems. Watches often had garnet, quartz, or even glass jewels; only top quality watches used sapphire, ruby, or diamond. In 1902, a process to grow artificial sapphire crystals was invented, making jewels much cheaper. Jewels in modern watches are all synthetic sapphire or (usually) ruby, made of corundum (Al2O3), one of the hardest substances known. The only difference between sapphire and ruby is that different impurities have been added to change the color; there is no difference in their properties as a bearing. The advantage of using jewels is that their ultrahard slick surface has a lower coefficient of friction with metal. The static coefficient of friction of steel-on-steel is 0.58, while that of sapphire-on-steel is 0.10-0.15.
Read more about this topic: Mechanical Watch
Famous quotes containing the words watch and/or jewels:
“It is indolence ... indolence and love of ease; a want of all laudable ambition, of taste for good company, or of inclination to take the trouble of being agreeable, which make men clergymen. A clergyman has nothing to do but be slovenly and selfish; read the newspaper, watch the weather, and quarrel with his wife. His curate does all the work and the business of his own life is to dine.”
—Jane Austen (1775–1817)
“This was Pharaoh, direct descendent of our deity Amon, god of the sun, who rules the heavens as Pharaoh rules the earth. Again, he brought treasure, gold, and precious jewels taken from our enemies. For to Pharaoh riches were power and power was to be desired. And also again he brought many captives. For is it not by slaves that one becomes even richer and then has even more power?”
—William Faulkner (1897–1962)