Electromechanical Calculators Home The Beginnings

Mechanical Calulating Devices


The Creation and Growth of Mechanical Calculators

Mechanical calculators and aids to calculation

John Napier, Logarithms and Napier's "Bones"

Perhaps best known for inventing Logarithms, John Napier had a wide reputation for other interests as well. These ranged from theology to farming to scientific discovery to invention. It is with his work on logarithms that enabled him to create a simple, yet powerful aid to calculation. This calculating device was made of several sticks (made from ivory or bone) marked with numbers on them. By moving the sticks into different positions complex multiplications or divisions could be reduced to simple addition and subtraction operations. Follow these links for more details:

The First Mechanical Calculator

In 1623 Wilhelm Schickard invented a calculating machine. In a letter to Kepler he described a mechanical method for performing the calculations that Kepler had written about. Schickard was a true Renaissance Man. He taught astronomy, mathematics, surveying, and even biblical languages such as Aramaic as well as Hebrew at Tübingen in Germany. His expertise extended beyond academic learning to include such diverse interests as engraving and inventing new machines. Not only did he create his calculating machine, but he also developed a machine that calculates astronomical dates and even one for Hebrew grammar.

Blaise Pascal and the Pascaline

When he was just 18, Pascal began a three year project to build an adding machine (the Pascaline or Pascals Gears). His motive was to help his father, a French tax collector, simplify his work. At the heart of this adding machine were eight movable dials that were turned with a stylus. You entered a number by "dialling" each digit on a dial. The second number is added by increasing each dial by the value of the next digit. This begins with the rightmost dial and moving to the left. The machine performed an automatic carry similar to the way an odometer increments the milage on a car.

The Invention of the Slide Rule

The first Slide Rule appeared in 1650 and was the result of a joint effort of two Englishmen Edmund Gunter and the reverend William Oughtred.

Gottfried Wilhem von Leibniz

About the time Leibniz travelled to Paris on political matters (1672) he began to put together the early designs for a new calculating machine that would go beyond the abilities of Pascal's Gears. The following year he continued his political ventures in England where a visit to the Royal Society gave him the opportunity to demonstrate his calculating machine even though it was not finished. It was not until 1694 that Leibniz completed his new multiplying calculator. Much of the delay was due to his other interests. One of the most important "other things" that he was involved in was the development of differential calculus, as described in a work published in 1684.

Gottfried Wilhem von Leibniz (1646-1716)
The Leibniz caclulating machine

The first calculating machine which was produced in large numbers was invented by the Frenchman Thomas de Colmar in 1820. This "Arithmometer" was the first of many mass produced calculating machines in the nineteenth century.

The next major step was the change to a "pin wheel" mechanism by a Swedish inventor Wilgodt T. Odhner. This site has more information on de Colemar and Odhner.

To operate an 1885 Felt & Tarrant "Comptometer" adding machine over the Web visit this web site

If you want to know how these calculating machines worked visit The Museum of HP Calculators

Timeline for Early Mechanical Calculators

Computers, Calculators and the Industrial Revolution

One of the main pioneers whose vision was to create a way to "calculate by steam" was Charles Babbage. A good site to begin your exploration of Babbage and his importance to the development of computers is the Charles Babbage Institute

Take a look at this detailed biography by J.A.N. Lee

His first design was the Difference Engine. Originally designed to calculate new error-free mathematical tables, the Difference Engine was never finished. While in the midst of the designs and prototypes for the Differen ce Engine, Babbage envisioned an even more useful calculating machine, the Analytical Engine.

Like the Difference Engine, Babbage never finished his Analytical Engine. This time Babbage did not abandon his work, rather his financial supporters withdrewn their money. If Babbage had been a better manager of his project and the funding, he may have been able to complete a working model of the Analytical Engine in his lifetime. When he died in 1871, his great dream seemed to die with him.

Many people have never heard of Charles Babbage, but his ideas were certainly revolutionary. Nearly 100 years before Howard Aiken (inventor of the Mark I) and Konrad Zuse (creator of the Z1) were to successfully build their general purpose calculating machines, Babbage had envisioned a machine with a "central processing unit" (called The Mill by Babbage) and a seperate area to store the data (The Store). His choice of punched cards to program his Analytical Engine would prove to be another leap foreward.

Here is a great Web Page about Charles Babbage written by seven year old J.A.N. Lee
Electromechanical Computers Home The Beginnings

Updated on July 23, 1999 by the webmaster at RBV Communications International