05/12/2021

005 – Vive la différence – 1822

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The half minute which we daily devote to the winding-up of our watches 
is an exertion of labour almost insensible;
yet, by the aid of a few wheels, its effect is spread over the whole twenty-four hours.
Charles Babbage

Charles Babbage held very strong views and expressed them forcefully from a very young age. On going up to Trinity College Cambridge he concluded that it offered a disappointing standard of mathematics tuition.

He was a visionary, co-specifying signals used in lighthouses, proposing a ‘black box’ recorder for monitoring status during a railway crash, he believed in decimalisation of the UK currency and proposed tidal power be exploited.

By this time actuaries, astronomers, engineers, navigators and surveyors were relying upon printed mathematical tables. 

These were manually calculated and there were inherent mistakes; the transcription and printing processes added further errors.  In the 1830s one analysis of forty volumes of numerical tables showed 3,700 errors, with little confidence that all had been discovered.

Babbage had a collection of more than three hundred volumes and it was these errors that inspired him to design a machine to faithfully calculate and then print the results.

1822 His machine applied the method of differences, that is an iterative approach that makes it unnecessary for the equipment to multiply or divide – this was his Difference Engine.

The Babbage design would have been huge.  1989-91 the Science Museum in London built this working Difference Engine v2.0.

Difference Engine 1 required 25,000 precision parts and would have weighed fifteen tons (tonnes).  Its requirements stretched current manufacturing capabilities and his search for a suitable maker led to a survey of the UK and continental European manufacturers in his 1832 book ‘On the Economy of Machinery and Manufactures’.

Babbage was an irascible character, routinely railing against the masses, referring to them as ‘the Mob’ and complaining incessantly of the street nuisances of his time.  He had an almost pathological distaste for the noise of organ-grinders.

Only a portion of his Difference Engine design was ever created. 

Babbage and Joseph Clement, the master toolmaker appointed to build the Difference Engine, soon fell out.  Clement had been persuaded to move home nearer to Babbage but promised compensation never materialised.  Clement stopped work in 1833.

Babbage shifted his attention to a more ambitious project, the Analytical Engine.  Work on this defined a difference machine with only 4,000 parts, but no effort was applied to build this v2.0 engine.

It was conceived to be `programmable’ to calculate any algebraic value; it was this device that was the first true computer design.  But Babbage constantly refined and changed his plans.

He died having never built a single device, his son, Henry Prevost Babbage, did later create six working engines to his father’s designs.  A part of one of these was sent to Harvard on its 250th anniversary in 1886; inspiring the designer of the Harvard Mark 1 computer. 

Babbage’s preserved brain is on display in the London Science Museum.

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