Flight computer volvelle. Image: Author.
An app is an interface for manipulating particular datasets. Rather than giving you unwieldy columns of data, the app presents information at the tips of your fingers, for quick scrolling and reference. In the 19th and 20th century, there was a simple, popular paper device that performed a similar function on the cheap. It’s called a volvelle, and the technology is hundreds of years old.
The handheld data machine has a long lineage, of which the volvelle and the app are only the most recent inheritors. In the first half of the last millennium, if you wanted to know what time it was, you used a small, expensive gadget called an astrolabe. By adjusting the finely-made dials to reflect the angle of the sun or a known star above the horizon, along with the current date, one could determine the time accurately within a few minutes. You can try this yourself, using this brilliant smartphone app for Android—never again wonder what time it is, as long as you can see the sun and have your smartphone with you!
Using circles to manipulate data is an ancient human means of analog computation. The famous Antikythera mechanism relied up clockwork gears of precise size to conduct its calculations, much as mechanical clocks did when they caught on in Europe in the 14th Century. But these devices, as weith metal astrolabes, were expensive, due to the fine metalwork required to manufacture them to any degree of accuracy. So, paper provided a more budget-conscious means for these “analog apps.”
A 15th century volvelle. Image: British Library
The first volvelles were included in astronomy books, dating back to the times of the Arabic golden ages, in the 11th and 12th Century. Scientists from North Africa and the Middle East also did groundbreaking work with astrolabes and clocks in the same period.
The 13th Century Majorcan writer Ramon Llull brought the volvelle to Europe, along with many other Arabic ideas. Llull was fascinated by an Arab device called a zairja, which was a mechanical divination device featuring rotating disks of letters that were meant to answer philosophical questions, and he worked it into his mystical writings. He borrowed volvelles from Arab scientists as well, to present astronomical information written on a circle of paper, which could be rotated to different orientations on a page of a book.
In the 19th Century, there was a resurgence of the volvelle as a device for information on any number of subjects. Jessica Helfand, in her compendium of latter day volvelle designs entitled Reinventing the Wheel, notes that many were created as advertisements. Sponsored by food manufacturers and other homewares companies, they would bill themselves as calculators for dietary information, teaching tools, or games and horoscope readers.
Nuclear Bomb Effects Computer. Image: Wikimedia
There were also serious volvelles, meant to provide quick access to technical information. Perhaps one of the most famous is the Nuclear Bomb Effects Computer, that allowed military scientists to quickly calculate the number of megadeaths a warhead might create (featured in Dr. Strangelove.)
A trigonometer. Image: the author
And they're still around today; I’ve been collecting volvelles and other sliding analog apps for years. Some of them are actually quite useful—I can never remember the trigonometric functions when I need them, and while I could always just Google it, my trigonometer analog app is a visualization to which I’ve become accustomed. And I love the feel of these objects in my hands.
Color wheel volvelle. Image: Author
They are solidly built, even if printed on paper. They have the feeling of a good ruler or mechanical pencil. Each is a minor technological marvel, designed to be kept at hand, in a desk drawer or bookcase, and used often, when circumstances require.
Outdated dieting volvelle. Image: Author
The printing may be fading a bit, but the sliding paper interfaces are just as magical to my fingers as the first time I ever flicked a touchscreen. We’ve been offloading information into “outsourced brains” for centuries, and it is nice to feel the lineage in its continuity, from cardboard to touchscreen.
Scroll through my collection of analog apps, and see how data used to be held in the palm of the hand, before touchscreens made it cool. Or use this software to print your own!