The British Museum has a very beautiful ancient exhibit - the Roman Cup of Lycurgus. But it is famous to a greater extent for its unusual optical properties. Under normal light, the goblet appears yellowish-green, and in transmitted light it acquires a deep wine-red hue. Only in 1990, scientists managed to reveal the secret of these unique properties, but how could such an effect be achieved in ancient times? After all, these are real nanotechnologies …
Lycurgus Cup at the British Museum.
The cup is a so-called diatret - a bell with double walls of glass, covered with a figured pattern. Its height is 16.5, and its diameter is 13.2 centimeters.
The earliest found diatrets date back to the 1st century. n. e., and their production reached its heyday in the III and IV centuries. Diatrets in that era were considered very expensive items and were available only to the rich. To date, about 50 of them have been found, and mostly only in the form of fragments. The Lycurgus Cup is the only diatret so well preserved.
Presumably, this amazingly beautiful goblet was made in the 4th century in Alexandria or Rome. But dating products made from inorganic materials is very difficult, and it may well turn out to be much more ancient than currently assumed. The place of its manufacture is also indicated very presumably, while proceeding from the fact that it was here that glassblowing craft flourished in ancient times.
Experts did not come to a consensus regarding the purpose of this cup. Based on its shape, many consider it to be a drinking vessel. And given the fact that the color of the cup also changes depending on the liquid poured into it, it can be assumed that it was used to determine the quality of the wine, or to find out if poison was added to the drinks.
There is another version regarding the use of diatrette. The peculiar edge on some of the surviving specimens, as well as a bronze ring on one of them, testify to the fact that they could have been used as lamps.
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It is also unknown how this goblet ended up among the treasures of the Roman Catholic Church, who found it, where and when. In the 18th century, it fell into the hands of the French revolutionaries, who later, in dire need of money, sold it. Someone, apparently for preservation, attached a base and a rim of gilded bronze to it.
In 1845, the banker Lionel de Rothschild bought the artifact for his collection, and 12 years later he caught the eye of the art critic from Germany Gustav Vaagen. Struck by the beauty and unusual properties of the cup, Vaagen tried to persuade the banker to show this treasure to the general public. Finally, he agreed, and in 1862, the goblet was exhibited for some time at the Victoria and Albert Museum in London.
After that, the cup again remained in a private collection for almost a century. But the researchers did not forget about it. In 1950, the owner of the cup, Victor Rothschild, one of the banker's descendants, allowed a group of scientists to take it for some time for research. It was then that it became clear that the goblet was not at all metallic, as was believed before, but was made of glass, but not ordinary, but containing layers of impurities of metallic oxides (dichroic glass). In 1958, yielding to numerous requests, Rothschild did a good deed and sold the cup to the British Museum.
Why the diatret was called the Lycurgus Cup
The plot of the high relief on the surface of the bowl recalls one of the famous myths of the ancient world about King Lycurgus.
Being an ardent opponent of libations and bacchic and orgies arranged by the god of winemaking Dionysus in the company of maenad companions, Lycurgus once, unable to bear it, beat them and drove them out of his territory.
High relief on the Lycurgus Cup: an angry king attacks Dionysus and his retinue.
The offended Dionysus decided to take revenge on the king for this and sent to him one of his most sultry beauties, the nymph Ambrose, who charmed and gave Lycurgus a drink. The drunken king fell into a frenzy, rushed to cut down the vineyard and in a frenzy hacked to death his mother and son.
Then Dionysus and the satyrs entangled the king, turning into grape stalks. Trying to get rid of them, Lycurgus accidentally chopped off his leg instead of a vine and soon died of blood loss.
But, perhaps, the cup depicts a completely different plot.
Modern research
After the goblet was handed over to the museum, scientists had more opportunities to study it. But, nevertheless, for a long time they were unable to reveal the secret of its unusual optical properties. Only in 1990, using an electron microscope, they finally figured out that it was all about the special composition of the glass from which it was made. For a million particles of this glass, there were three hundred and thirty particles of silver and forty - gold. Moreover, the silver and gold contained in the glass had the size of nanoparticles. Only in this case glass has the ability to change color, which is observed.
Of course, the question immediately arises - how were the ancient ancient masters able to carry out work in the literal sense at the molecular level, requiring both the most sophisticated equipment and the highest level of technology?
Or maybe they didn’t make the Lycurgus Cup at all? And, being much more ancient, it is a trail of some unknown and sunk into eternity of highly developed civilization that preceded ours.
Physicist Liu Gann Logan of the University of Illinois, working in the field of nanotechnology, suggested that light or liquid entering the goblet interacts with the electrons of the nanoparticles contained in the glass. Those, in turn, begin to vibrate at one speed or another, and this speed already determines what color the glass will have.
Of course, to test this hypothesis, scientists could not use the cup itself, filling it with various liquids. For these purposes, they had to make a special plate with a similar composition of gold and silver nanoparticles. And, indeed, it turned out that in different liquids the plate had a different color. So in water it acquired a light green color, and in oil - red. Only now, scientists failed to reach the level of the ancient masters who made the cup - the sensitivity of the plate turned out to be a hundred times lower than that of the cup.
But, nevertheless, scientists propose in the future, using the studied properties of glass with nanoparticles, to create various sensors. So the work begun by the ancient masters in this direction continues.
Several more similar glass "chameleons" have been discovered, but all of them are inferior in beauty to the famous goblet.
Fragment of a Roman diatrette in reflected (left) and transmitted light. Length 6.5 cm, width 9 cm. British Museum.