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# 2.1 Mechanical arithmetic

Counting boards and paper calculations are some way from the digital thinking tools of the 21st century. But they did lead to another breakthrough – the realisation that calculations can be mechanised. Moving counters on a board, or doing pen-and-pencil calculations, are mechanical processes. They do not have to be carried out by a human being – they can be automated.

Figure 8 shows a modern replica of what might have been the first mechanical calculator described. This was the ‘arithmetical instrument’ invented by German professor Wilhelm Schickard, who wrote about it in letters between 1623 and 1624. Devices like this owed much to the technology used to make clocks. They had moving parts, gear wheels and other mechanical components.

Figure 8 Replica of Schickard’s arithmetical instrument

However, it was not until 1851 that a commercially successful calculating machine was launched. This was the arithmometer, which could do all four operations of arithmetic: addition, subtraction, multiplication and division.

The Gentleman’s Magazine wrote about it in 1857. (Note that the word ‘calculators’ in the final sentence refers to human calculators.)

Instead of simply reproducing the operations of man’s intelligence, the arithmometer relieves that intelligence from the necessity of making the operations. Instead of repeating responses dictated to it, this instrument instantaneously dictates the proper answer to the man who asks it a question. It is not matter producing material effects, but matter which thinks, reflects, reasons, calculates, and executes all the most difficult and complicated arithmetical operations with a rapidity and infallibility which defies all the calculators in the world.

The author of this article regarded the arithmometer as performing mental tasks; in other words as a tool to aid thinking. It extended human capabilities by doing arithmetic much faster and more accurately than had been possible before.