This is the third and final post in Amanda Malkin’s series exploring geometric patterns in Islamic paintings, focusing on the possible use of optical devices by the manuscript illustrator. Previous posts discussed Geometric Patterns in Islamic Paintings and Tools of the Manuscript Illustrator.
The first true magnifying lens—an instrument with a handle created for the purpose of magnification—was developed in 1250 CE by Roger Bacon in England. However, a large group of archaeologists and scientists believes that ancient cultures were experimenting with rudimentary optical devices, made from rock crystal, many centuries before Bacon.
Rock crystals with plano-convex surfaces dating from 2500 BCE to 1500 BCE have been found in Egypt, Greece, and Mediterranean cities. Many of these rock crystals were of optical quality, according to the definition put forth by Dominic Ingemark in his article “A Rare Rock-Crystal Object from Pompeii.” That is, the rock crystal is acceptably transparent and homogeneous with at least one surface that is curved with minor surface irregularities. Additionally, the crystal must be able to form a reasonable image.
There is an interesting, ongoing debate regarding the function of these highly valuable rock crystals. Some theories suggest they were used as decoration on furniture, game pieces, or medical instruments. Ancient sources describe bi-convex lenses—basically, glass or rock-crystal balls—that were used to cauterize wounds or remove tissue. These sources do not mention the use of plano-convex lenses as optical devices, and this absence is convincing evidence, for some, that they were not used as such.
However, other scholars argue that the craftsmen who made the “lens-shaped objects,” as they are sometimes called, would have had to use an optical device themselves to do such precise work. The minute, archaic decoration on engraved gems, coins, cylinder seals, intricate jewelry, and of course, manuscript illustrations also suggest that lenses were present and used. The quality and precision of the microscopic ornamentation seem inconceivable without the use of magnifying lenses.
A controversial theory suggests that, instead of using lenses, men with myopia, or nearsightedness, were sought out and trained as craftsmen. Their distorted, magnified vision could have been exploited for creative purposes. The hypothesis, based on thoughtful and clearly investigated theories regarding genetics and a possibly high occurrence of myopia in early civilizations, remains an over-reaching argument. It seems unrealistic to believe that, even with extensive training, men with myopia could have become the majority of master engravers. Their optic handicap would have hindered their work as apprentices: Publications state that master engravers traditionally dealt with the raw stone and carried out the intricate work, while their assistants did the grinding and polishing.
The lack of written historical evidence confirming the function of these somewhat mysterious objects has made this research incredibly intriguing. Although the results are inconclusive, it is certain that as more plano-convex rock crystals are unearthed, more knowledge and information will follow.