The First Mechanical Calculator and the Computer Revolution of the 1600's

The World in 1623

The year was 1623. William Shakespeare had died only 7 years earlier. The Salem Witch Trials were still 69 years away. The total European population of what would become the United States was less that 3,000 people, while the Native American population would not begin to be recorded for another 237 years. A trip to England from the colonies took over two months, and the Pilgrims had landed in Plymouth only 3 years earlier. And the first known mechanical calculator was built in Germany.


Wilhelm Schikard

Wilhelm Schikard was born in 1592, and while he was a respected academic while he lived it was not until the later half of the 20th century that his true contribution to the history of computing was realized. Shikard was a professor of Hebrew and Astronomy in Germany at the University of Tübingen and a regular correspondent of Johannes Kepler, the namesake of the planet hunting telescope currently orbiting the earth.

 Schikard in 1632

The Mechanical Calculator

It is in one of the correspondences to Kepler that Schikard first describes his mechanical calculator in 1623, which he refered to as the “arithmetical organum” (“arithmetical instrument” in English). The calculator had many flaws, and does not look like what we think of as a calculator or computer today. The user entered data on a series of wheels and an abacus like arrangement. The machine could perform addition and multiplication, but not subtraction or division. The design was mechanically fragile, and a “roll-over”, for example form 999 to 1,000 would cause the single tooth cogs to fail. This, perhaps, is the reason that Blaise Pascal was credited with the invention of the mechanical calculator nearly 20 years later.

Schikard's original calculator sketch

This historical inaccuracy was rectified by modern historian Franz Hammer, who re-discovered Schikard’s letters to Kepler. Upon further investigation Hammer discovered that Schikard’s calculator was not as forgotten as it may have seemed. Hammer found references and republications of Schikard’s work starting in 1718 (the first public publication), with his drawings and designs being rediscovered at least once per century until modern times.


It is also important to note that Schikard’s drawings do not describe a fully functional machine. Schikard, in describing his machine to Kepler, states that the machine works. It is reasonable to assume that certain parts of the machine were omitted from the drawings to protect Schikard’s invention, and indeed later replicas of the machine function when additional gears are added to his design. This part of the story will remain a mystery, however, as no one beyond Schikard is known to have seen a working prototype. For this an other reasons many historians dispute whether Schikard or Pascal invented the mechanical calculator.


Pascal's Calculator

Impact on the World

Whether Schikard or Pascal was first, their work sparked a miniature computer revolution over 350 years before Apple and Microsoft’s epic showdown. Many mechanical calculators were designed during this time, each improving on the last. It wasn’t until two hundred years later, however, that the first programmable computer would be described.