About +520 envoys of Fu-sang are said to have arrived in China, bringing with them a precious stone suitable for observation of the sun (kuan jih yu) 'of the size of a mirror, measuring over a foot in circumference, and as transparent as glass (liu-li); looking through it in bright sunlight, the palace buildings could be very clearly distinguished'.
In the centuries that followed, we hear of "fire pearls" (huo chu 'fire orb, pearl') repeatedly offered as gifts by various countries to the Chinese court. The Chinese texts identify prime sources of fire pearls as the countries of Lo-ch'a, Tan-tan and Po-li. While the exact location of these countries is open to debate, the texts clearly place them in Southeast Asia. The Tang Shu says this about the fire pearls from Lo-ch'a and Tan-tan.
Their country produces fire-pearls in great number, the biggest attaining the size of a hen's egg. They are round and white (transparent), and emit light to a distance of several feet. When held against the rays of the sun, mugwort and rush (tinder) will be ignited at once by fire springing from the pearl. The material looks like rock-crystal.
The small size of the fire pearls and the fact that they are like but not rock crystal (clear quartz) suggest they could be tektites, the natural glass gems probably formed by the collision of some extraterrestrial body on the Earth's surface. Tektites are often globular in form and they can range from opaque to nearly as transparent as silica glass. Such transparent, orb-shaped tektites would have a natural magnifying ability.
As the fire pearls were natural, small, round and transparent, and apparently not found in China but common in regions to the South, it is highly probable that tektites were meant.
Tektites were used to make flaked tools in the Neolithic period of Southeast Asia and polished tektites were apparently used as charmstones starting around the metal age. Some early Indochinese Hindu-Buddhist deity statues have polished tektites placed in the eye sockets.
During T'ang times, we see a close association between the huo chu and the dragon. A T'ang bracelet at the Shosoin in Japan has two facing dragons holding a fire pearl. This motif and a related one with a huo chu between the mouths of two facing dragons has continued until present times. Often the fire pearl in this depiction is decorated with a spiral or is surrounded by a wreath of flames. Pearls are said to be found in the mouths of dragons something possibly alluded to earlier by Zhuangzhi. It was common during this period to classify the whale (King 'male whale', I 'female whale') as a type of sea dragon. Probably in connection with this concept, the naturally phosphorescent eyes of the whale, particularly the female whale of the South Seas, were known as "moonlight pearls" having the "brilliancy of the night." There may be some connection here also with the use of polished tektites as "eyes" in Indochinese sculpture.
In latter times, one of the Dragon Kings of the sea is located along with his palace on the blessed island of Penglai, apparently a conflation with the King Father of the East. In Japanese lore, the land of Tokoyonokuni, linked in the Nihonshoki with Mount Horaisan (Penglai), is also the home of the Dragon King of the Sea. The Dragon King's palace is said to be made of rock-crystal (shui ching).
While the fire pearl was linked more with the sea, there is also a hint of heavenly origin as found in Southeast Asia with reference to tektites, where the latter are known by names such as star dung, sun stones, moon stones, thunder dung, etc. The term "huo chu" was used in pre-T'ang literature to refer to fiery meteors, and we know that the Chinese dragon flies through the sky and is associated with storms, thunder and lightning. G. Elliot Smith, following Koh Hung, thought the spiral design on fire pearl iconography represented the rolling sound of thunder.
(Left) Three Australian button tektites and (right) three glass models ablated by aerodynamic heating; actual size ranges from 16 to 25 mm (Encyclopædia Britannica)
The Gaozhang empress Wu Zhao had the great Mingtang ('Hall of Light') built to worship Heaven in 688 CE. A giant iron phoenix on the roof of the 85 meter wide, three-story octagonal structure was blown down by wind, and replaced with a fire pearl. The name was changed to Tongtianwu ('Hall that Connects with Heaven'). After Wu Zhao usurped the T'ang house to form the Zhou Dynasty in 690 CE, Wu Sansu, her nephew, along with some "tribal chiefs" set out to construct a massive pillar in honor of Wu Zhao.
Completed in 695, the Tianshu ("Heavenly Pillar") was 30 meters high and 5 meters wide and stood atop a mountain of iron decorated with a bronze dragon and unicorn. On top of the pillar, four "dragon men" sculptures held up a fire pearl.
Optics in Ancient and Medieval China
Mirrors in China appear in the oldest strata of literature, and references to the concave bronze mirrors, the yang-sui, that collects the Sun's rays; and the fang-zhu, that gathers the dew from the Moon, date back to at least the Zhou Dynasty.
The yang-sui is mentioned during Zhou times as a burning mirror capable of igniting kindling placed at its center under the light of the Sun.
Interest in burning lenses, rather than mirrors, perks up in the T'ang Dynasty with the importing of the fire pearls from Southeast Asia and elsewhere. However, it was during the Sung Dynasty that we see a real upswing in optics research in China. In the 10th century, the Daoist teacher Tan Qiao (Than Chhiao), wrote about lenses and mirrors. He describes four types and properties of lenses:
I have always by me four lenses. The first is called kuei (the 'sceptre', a diverging bi-concave lens). The second is called chu (the 'pearl', biconvex). the third is called chih ( the 'whetstone,' plano-concave). The fourth is called yu (the 'bowl,' plano-convex).Tan Qiao's work Hua Shu is dated to about 940 CE, so he predates the noted Arab physicist Ibn al-Haitham by several decades. In the 11th century, Shen Gua (Shen Kua) wrote of similar properties with reference to concave, convex and flat mirrors.
With kuei the object is larger (than the image).
With chu the object is smaller (than the image).
With chih the image appears upright.
With yu the image appears inverted.
When one looks at shapes or human forms through such instruments, one realises that there is no such thing as (absolute) largeness or smallness, beauty or ugliness..."
The ancients made mirrors according to the following methods. If the mirror was large, the surface was made flat (or concave) ; if the mirror was if the mirror was small, the surface was made convex. If the mirror is concave (wa) it reflects a person's face larger, if the mirror is convex (tieh) it reflects the face smaller. The whole of a person's face could not be seen in a small mirror, so that was why they made the surface convex. They increased or reduced the degree of convexity or concavity according to the size of the mirror, and could thus always make the mirror correspond to the face.
That a concave mirror could be used to view objects at a great distance was known to the Chinese. In 1225, Chau Ju-Kua (Zhao Rugua) wrote about the great lighthouse in Pharos.
The country of O-Ken-Tho (Alexandria) belongs to Egypt (Wu-Ssu-Li). According to tradition, in olden times a stranger (i jen), Chhu-Ko-Ni by name, built on the shore of the sea a great pagoda, underneath which the earth was excavated to make two rooms, well connected and thoroughly hidden. In one vault was stored grain, and in the other arms. The tower was 200 ft. high [Note: chang = 10 feet, chhih = 1 foot]. Four horses abreast could ascend (by a winding ramp) to two-thirds of its height. Below the tower, in the middle, there was a well of great size connected by a tunnel with the great river. To protect this pagoda from foreign soldiers, the whole country guarded it against all enemies. In the upper and lower parts of it twenty thousand men could readily be stationed as a guard or to make sorties. At the summit there was an immense mirror. There was an old story said that if warships of other countries tried to make an attack, the mirror detected them beforehand, and the troops were ready to repel it. But in recent years there came (to Alexandria) a foreigner, who asked to be given work in the guardhouse below the tower, and he was employed to sprinkle and to sweep. For years no one entertained any suspicion of him, but suddenly one day he found an opportunity to steal the mirror and throw it into the sea, after which he made off.Chau Ju-Kua was relaying a story told in Arabic works of a great mirror on the Pharos lighthouse that allowed the ruler to see events throughout the kingdom and according to some versions to detect fleets more than 100 leagues away.
According to Abu-l'fida (1331), this mirror was made of "Chinese iron" or "kharsini," indicating that the mirror was installed by Muslim rulers. Chinese mirrors are mentioned by al-Razi as being sold in 990 CE for up to several times their weight in silver in Baghdad. Al-Dimashqi in 1325, refers to "distorting mirrors" made of kharsini.
Concave mirrors up to three feet in diameter are described in the 4th century CE work Shi-I-Ki, and other sources tell of fabulous mirrors capable of casting light at distances up to 200 li.
We have noted earlier, that both the King of Shambhala and Prester John were said to have mirrors or lenses that allowed them to observe things throughout their kingdom or beyond. In the Letter of Prester John, this mirror is located in the tower of the king's palace. Edwin Bernbaum writes about the King of Shambhala: "According to descriptions of the King's palace in Kalapa, special skylights made of lenses act like high-powered telescopes to reveal life on other planets or solar systems. The King also possesses a glass mirror in which he can see scenes of whatever is happening for miles around."
Whether such a mirror existed is possibly not so important as the esoteric ideas involved. In this connection, we may also consider the crystal palace of the Dragon King of Penglai, and the relationship between whale (dragon) eye pearls, and possibly the eyes of deity statutes, with fire pearl lenses.
There is an interesting linguistic reconstruction with reference to the burning and observation lenses brought from Southeast Asia to China starting in the T'ang era. There exists the suggested prototype *sjaLemin for Tagalog salamin 'mirror, spectacles, glass, crystal," Toba Batak sormin; Malay chermin "mirror," Ngaju Dayak saramin "mirror, glass, Bisaya salamin "crystal, mirror," Kapampangan salamin "mirror, spectacles," etc.
Some have challenged this reconstruction suggesting instead that the words mentioned above are borrowed from Sanskrit carmin "made of leather,' via a rather convoluted argument. I would have to say the reconstruction has a better chance of being true.
Pigafetta speaking about the kingdom of Brunei in 1521 states:
The merchandise which is most esteemed here is bronze, quicksilver, cinnabar, glass, woollen stuffs, linens ; but above all they esteem iron and spectacles.
The quote above may be the first mention of eyeglasses as a trade item. Up until Pigafetta's time, glasses were apparently quite rare anywhere in the world.
Chinese texts, in fact, state that the first spectacles (ai-dai) in China were brought from Malacca (Man-la-chia) as a present from that kingdom's ruler. These were quite different than early spectacles from the West as they were made from rock crystal and were monoculars that could be attached together. The earliest use of rock crystal (shui jing) in China for such purposes was prior to 1117 by Sung Dynasty judges who used rock crystal magnifying glasses to decipher poorly-written or preserved documents. The ai-dai also came to have a 'tea lens' (smoky quartz) variation to protect the eyes from sunlight.
Paul Kekai Manansala
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Cheung, Frederick Hok-ming, and Ming-chiu Lai, eds. Politics and Religion in Ancient and Medieval Europe and China, Hong Kong: Chinese University Press, 1999.
Needham, Joseph, Wang Ling, Ling Wang, Kenneth Girdwood. Science and Civilisation in China vol. IV, Cambridge University Press, 1962, 87, 114-120.
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