Computers Before Babbage: Schickard’s 17th Century Mechanical Calculator

Charles Babbage’s Difference Engine is now considered to be the first computer. Designed in the 19th century by the pioneeering mathematician, it was designed to prevent human error in the calculation of mathematical tables used for vital tasks, such as navigation. Wholly mechanical, it proved far too expensive for the British government to fund completely and so was never built. A replica of part of it stands in the Science Museum in London, while another replica was built for the home of Charles Simonyi, the vice-chair of Microsoft. As an icon of Victorian technological excellence and information technology, it has also been an inspiration to Steampunk Science Fiction novelists. This is most explicit in William Gibson and Bruce Sterling’s 1990 The Difference Engine.

Yet there is a whole history of mechanical computers extending back as far as the 17th century. The first of these was the ‘calculating clock’ built by the German polymath, Wilhelm Schickard in 1623. Schickard was inspired by the calculating aid, Napier’s Bones and incorporated them into his own device. The Calculating Clock was the size of a typewriter using a direct gear drive and rotating wheels to perform addition and subtraction. The machine used Napier’s Bones in its upper section to multiply and divide.It could computer figures up to six digits in length. Below these were a line of wheels and dials for addition and subtraction lay below them. The wheels were arranged so that when one wheel made a complete turn, the next moved a tenth of a complete turn. The dials were connected by toothed internal wheels that brought forward one digit whenever the wheel passed from nine to zero. The dials were moved in different directions for addition and subtraction. If the result of the calculation could not be displayed because it was longer than six digits, a bell rang.

Unfortunately, like many great inventions, including Babbage’s Difference Engine, it was never built. Schickard was building a replica of the calculating clock for the great astronomer, Kepler, when his workshop was destroyed by a fire. He gave detailed instructions for its construction to Kepler, before Schickard and his family were all killed by the plague in the 1630s. It was only rediscovered in the 1950s amongst Kepler’s papers held in Russia.

Despite this, it’s an astonishing demonstration of the mathematical and engineering ingenuity of the early 17th century, and makes you wonder what else they were capable of, and even how unique are the modern scientific achievements of our own day.


Tags: , , , , , , , , , , , , , , , ,

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: