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Crystal ball sitting in snow

The Art of Prediction: Why Meteorologists Use Crystal Balls to Measure Time


Incidence of crystal balls in the history of magic can be well explained in how they’re used to predict the weather.

Of all the paraphernalia surrounding magic, the crystal ball has an exceptional place. We see it in representations of ancient magicians, with fortunetellers at the carnival, consulted by iconodule oracles and in the windows of esoteric shops around the world. It is not hard to deduce that its insistence in the history of magic has to do with its shape, which resembles the eye, the moon and the well, all signs that give back images of time –– All of them mirrors in which the world is seen… and as Octavio Paz would say, “To see the world is to spell it out.”

It is therefore that reading a spherical reflection (an aleph where the three tenses meet) is one of the divination tools that are more profuse in history. The first to use a crystal ball as a method of divination were called the specularii. They were Celtic Druids of Gaul, Britain and Ireland who gathered beryllium, a greenish, translucent mineral, and polished it to a spherical shape to see there what would happen in the future. Later, in the Middle Ages, magicians, clairvoyants, Gypsies and physicians began using rock crystals for the same purpose. According to the writer Northcote W. Thomas, who wrote a fascinating book on crystallomancy in 1905, in the era of preindustrial divination all kinds of materials (from quartz to blood collected in a bowl) were commonly consulted by Pawnee, Iroquois, Inca, Egyptians, Persians, Chinese and Mayan people.

Renaissance woman holding crystal ball

But not only that –– Crystal balls, whose persuasive charm is not easy to ignore, are also used in meteorology as one of the most accurate ways of measuring the intensity of sunlight. At the South Pole there are two crystal balls that provide – just like those used by ancient magicians –information about time, though not the future but of the past.

The two South Pole spheres are Campbell-Stokes recorders, which track the duration and intensity of sunlight each day of the year. It’s not surprising that the person who invented this way of measuring light had been a student of Celtic folklore: John Francis Campbell.

When inventing his beautiful sunshine recorder in 1853, Campbell knew of burning glasses whose convex lenses could focus the sun’s rays to create an intense beam of heat and light. These same burning glasses, according to Archimedes, were used in Greek mythology to burn a fleet of Roman enemies.

Ship being struck by beams from large glass weapon

Armed with his knowledge of physics and with the history of the Celtic Druids, Campbell found a way to not only trace the path of the sun but also to record the intensity of its light over the course of one day. Each hollow sphere was built from glass 6 inches thick, and placed onto a tumbler rising from a wooden bowl. When the crystal ball was directed to the South, the sun scorched the wooden bowl and traced its way across it. The more intense the sunlight, the deeper the engraving.

The design worked perfectly for meteorologists until 1879, when the mathematician and physicist Sir John Gabriel Stokes (the “Stokes” in Campbell-Stokes) ingeniously modified it. Instead of letting the sun singe a wooden bowl, which had to be changed every day, Stokes introduced removable cards made of thick paper that were replaced every day and contained them in a metal bowl.

The Campbell-Stokes recorders are still used today, and though they’re perhaps the least known of all crystal balls as tools for measuring time, they are symbol and proof of their portent. When looking at the past through one of them, one can then glimpse the future that has so tempted societies. One can even anticipate the state of the weather, and what future is there with more ecumenical than the weather?

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