The early contributions of ancient America in optics predate those of european and arabian documentation, but are little known to our present culture and left no written description. If by written we understand words or a technical scheme. Nevertheless, their presence in the cultural remainings is unquestionable and its artifacts are well preserved and displaying wonderful images at museums in Mexico and Peru. Its heritance traversed centuries and cultures, and by some reason was not registered when Spain conquered the continent. Plane, concave and convex mirrors where part of the life of the governing elite and could had being the subject of admiration for the people. At the Central part of the continent the remainings are dated as from 2,800 years ago, and at the South could be as old as 3,500 years.
Short after Columbus landed in America the invaders dominated its three largest civilisations: The Aztec, Maia, and Inca empires. His frenetic search for gold and silver maybe distracted them to look to high quality stone artifacts, probably still present at that moment. His ignorance of the local languages too, or the resistance and denial of the natives to collaborate, maybe was a barrier to knowing those evolved technologies.
It may sound as just speculation, but who knows the history of humanity and science also knows how many findings remained unknown for a long period due to negligence on its of consideration. It is common in literature to read that the natives admired the mirrors the spanish conquerors brought, but it was not thought that this miraculous objects could had being the subject of admiration through centuries and cultures, being in the hand of only a few authorities. On the archaeology field, a bibliographic reference comes from 1926 (1) followed by another in 1959 (2) and followed by a dozen of others (3), always referring to Central America, or to the north of South America.
But a very first reference comes from the XVI century in a book written in South America where the author collects the oral testimonials of natives about his pre-columbian culture and a mirror appears as a sacred element to make fire on ceremonies (4).
A brief description
From the references we have, the oldest mirror manufacturers were civilisation named Cupisniques, with findings at Peru, which could be 3,500 years old. Their plane mirrors shows a good imaging quality (see Figure above).
When describing elements from this civilisation, it is interesting to know that a quartz element made for a necklace which it is also at the Larco Museum in Lima, Peru, has an enlarging capability of x10 if employed as a magnifying glass. Many more examples of stone mirrors, usually of about 20% reflectivity, can be found at another museums in Lima (5).
Could this sophisticated technology had been transfered to other civilisations? It is an interesting question to be solved by anthropologists. If so, could it had reached Central America? Or conversely, could mirror technology from Central America had reached South America? Although cultural exchange between those civilizations is a possibility, the technical characteristics of the findings uncovered up to now indicates the opposite. To my knowledge, the mirrors found at Peru are plane elements, while those from Mexico always has curvature, concave or convex.
We see in the Figure below two concave mirrors from the Olmec civilization showing how a line object appears imaged. The line object is a fluorescent lamp above them.
A better image is one of a hand located in front of one of those mirrors, as we can see on the following image.
And, to give a more convincent result, we see the high quality of imaging of a convex Olmec mirror, dated 800 BC, when a well defined printed figure is in front of them (2).
Which use would this mirrors had? It is a matter of supposition, but many applications can be thought (6), and the reader itself may imagine some. Self contemplation, of course, directing light for illumination of dark places, religious and political applications, etc.. And, regarding image quality, how could them be compared with those from other continents, as from China, for example? (7).
1 – Nordeskiold, E. (1926), “Mirroirs convexes et concaves en Amérique”, Journal de la Societé des Americanistes de Paris, n.s. tome XVIII, Paris, 102-110.2)
2 – Gullberg, J.E. (1959), “Technical Notes on Concave Mirrors” in Excavations at La Venta, Tabasco, 1955, Smithsonian Institution Bureau of American Ethnology, Bulletin 170, United States Government Printing Office, Washington, USA, 280-283 and pl.62.
3 – Lunazzi, J.J., “Olmec Mirrors: an Example of archaeological American mirrors”, chapter 22 of the book “Trends in Optics” V3 published by the International Commisssion for Optics – ICO, Ed. Anna Consortini, Ac. Press. 1996, p411-421.
4 – de la Vega, Garcilaso (1617), “Libro Sexto de los Comentários Reales de los Incas”, ch. XXII.
5 – Lunazzi, J.J., “Óptica precolombina del Perú”, Revista Cubana de Física, V. 24, N2, 2007, p.170
6 – Lunazzi, J.J. “On How Cupisnique and Olmec Mirrors Would Have Been Employed”, chapter 6 of the book “Manufactured Light-Mirrors in the Mesoamerican Realm”, edited by Emiliano Gallaga and Marc G. Blainey, University Press of Colorado, December 2015. Hardcover ISBN: 978-1-60732-407-2, EISBN: 978-1-60732-408-9
7 – Ling-An Wu et. al., “Optics in Ancient China”, AAPPS Bulletin, V. 25, N.4, p. 6-10, August 2015.
José Joaquín Lunazzi was born in La Plata, Argentina, and was invited to join his present university at Campinas City, São Paulo, Brazil in 1975. He promoted metrologic and holographic techniques and applied them to engineering, for the first time in Argentina. He taught optics at every level. He has performed many interviews in Argentina, Brazil, Italy and USA media. And had produced many didactical exhibits since 1981, including a daily exhibit for the IYL 2015. He found hidden properties in holographic and diffracted images extending its use to white light and electronic imaging. He introduced the subject of archaeological optics into the optics community in 1975.