The Lenses of the Vikings.

archiv10The high precision Lenses of the Vikings.
Today’s aspherically ground glasses for high precision optical instruments are generally held to be an achievement of our highly technological world, a product of the computer age. A mistaken view. Actually, the first such instruments date back to the 12th century. After several years of painstaking analyses, eyeglass experts have now confirmed that the ground rock crystal objects from the 12th century found in Swedish Viking graves were made almost to perfection.
If the lens is placed on a text page, the effect is the same as that obtained with a modern magnification glass measuring 5cm in diameter. It was not until the 17th century that mathematician René Descartes successfully made theoretical calculations about aspherical lenses. However, this precision technology was not known to have been used in practice before the 20th century. So how did they develop such sophisticated optical devices 8 centuries ago? Researchers from the University of California at Berkeley now want to further investigate the sensational “Viking” lenses. It is generally believed that the unusual items were originally manufactured in Byzantium, where they were purchased or stolen by the Vikings.
Place of discovery: Viking graves on the Baltic Sea island of Gotland, Sweden
Age: 12th century or earlier