|The Nimrud lens|
|Size||Diameter: 38 mm (1.5 in)|
Thickness: 23 mm (0.9 in)
Assyrian palace of Nimrud
|Discovered by||Austen Henry Layard|
|Place||North West Palace, Room AB|
|Present location||British Museum, London|
The Nimrud lens, also called Layard lens, is an 8th-century BC piece of rock crystal which was unearthed in 1850 by Austen Henry Layard at the Assyrian palace of Nimrud in modern-day Iraq. It may have been used as a magnifying glass or as a burning-glass to start fires by concentrating sunlight, or it may have been a piece of decorative inlay.
The lens is slightly oval and was roughly ground, perhaps on a lapidary wheel. It has a focal point about 11 centimetres (4.5 in) from the flat side and a focal length of about 12 cm. This would make it equivalent to a 3× magnifying glass. The surface of the lens has twelve cavities that were opened during grinding, which would have contained naphtha or some other fluid trapped in the raw crystal. The lens is said to be able to focus sunlight although the focus is far from perfect. Because the lens is made from natural rock crystal, the material of the lens has not deteriorated significantly over time.
The Nimrud lens is on display in the British Museum.
The function of the lens is not clear, with some authors suggesting that it was used as an optical lens and others suggesting a decorative function.
Assyrian craftsmen made intricate engravings and could have used a magnifying lens in their work. The discoverer of the lens noted that he had found very small inscriptions on Assyrian artefacts which he suspected had been achieved with the aid of a lens.
Italian scientist Giovanni Pettinato of the University of Rome has proposed that the lens was used by the ancient Assyrians as part of a telescope and that this explains their knowledge of astronomy (see Babylonian astronomy). Experts on Assyrian archaeology are unconvinced, doubting that the optical quality of the lens is sufficient to be of much use. The ancient Assyrians saw the planet Saturn as a god surrounded by a ring of serpents, which Pettinato suggests was their interpretation of Saturn's rings as seen through a telescope. Other experts say that serpents occur frequently in Assyrian mythology and note that there is no mention of a telescope in any of the many surviving Assyrian astronomical writings.
According to his book, Layard found the lens buried beneath other pieces of glass which looked like the enamel of an object, perhaps made of wood or ivory, which had disintegrated. The British Museum curator's notes propose that the lens could have been used "as a piece of inlay, perhaps for furniture" and that there is no evidence that the Assyrians used lenses for their optical qualities, e.g. for magnification, telescopy or for starting fire.
A similar object was mentioned in The Epic of Ishtar and Izdubar, Column IV, Coronation of Izdubar, written about 2,000 BC. 10th stanza. It reads:
The King then rises, takes the sacred glass,
And holds it in the sun before the mass
Of waiting fuel on the altar piled.
The centring rays—the fuel glowing gild
With a round spot of fire and quickly. spring
Above the altar curling, while they sing!
- Layard, Austen Henry (1853). Discoveries in the ruins of Nineveh and Babylon: with travels in Armenia. G.P. Putnam and Co. pp. 197–8, 674.
- D. Brewster (1852). "On an account of a rock-crystal lens and decomposed glass found in Niniveh". Die Fortschritte der Physik (in German). Deutsche Physikalische Gesellschaft.
- "The Nimrud lens / the Layard lens". Collection database. The British Museum. Retrieved Oct 21, 2012.
- Villiers, Geoffrey de; Pike, E. Roy (2016-10-16). The Limits of Resolution. CRC Press. ISBN 9781315350806.
- Whitehouse, David (July 1, 1999). "World's oldest telescope?". BBC News. Retrieved May 10, 2008.
If one Italian scientist is correct then the telescope was not invented sometime in the 16th century by Dutch spectacle makers, but by ancient Assyrian astronomers nearly three thousand years earlier. According to Professor Giovanni Pettinato of the University of Rome, a rock crystal lens, currently on show in the British museum, could rewrite the history of science. He believes that it could explain why the ancient Assyrians knew so much about astronomy.
- "World's oldest telescope?". EXN Science Wire. June 29, 1999. Archived from the original on September 29, 2007. Retrieved 2008-05-10.
Pettinato believes the lens was used by Assyrian astronomers as a telescope more than three thousand years ago. They saw more in the night sky than was possible with the naked eye alone. For example, the Assyrians saw the planet Saturn as a god surrounded by a ring of serpents. Pettinato says that would be a logical assumption to make if they saw Saturn's rings through a primitive telescope.
- "Column IV, Coronation of Izdubar". sacred-texts.com. Retrieved 2020-12-31.
- A. H. Layard, Discoveries in the Ruins of Nineveh and Babylon (London, 1853), p. 197–98.