Charles Babbage

Charles Babbage (December 26, 1791- October 18, 1871) was an English mathematician and (proto-)computer scientist who was the first person to come up with the idea of a computer. Parts of his uncompleted mechanisms are on display in the London Science Museum. In 1991, working from Babbage's original plans, a Difference Engine was completed, and functioned perfectly. They were built to tolerances achievable in the 19th century, indicating that Babbage's machine would have worked.

Early Years

Born in Teignmouth, Devonshire, he was an alumnus of Trinity College, Cambridge and of Peterhouse College, Cambridge. He graduated from Cambridge in 1814. In that same year, he married Georgiana Whitmore. They had eight children, but only three lived to adulthood. Mrs Babbage died in 1827.

Design of Computers

In recognition of the high error rate in the calculation of mathematical tables, Babbage sought to find a method by which they could be calculated by machine, which would not suffer the errors, fatigue and boredom of human calculators. This idea had come to him as early as 1812. Three different factors seem to have influenced him: a dislike of untidiness, his awareness of logarithmic tables, and work on calculating machines carried out by Blaise Pascal and Gottfried Leibniz. In 1822, in a letter to Sir Humphrey Davy on the application of machinery to the calculation and printing of mathematical tables, he discussed the principles of a calculating engine.

Difference Engine

He presented a model of what he called a Difference Engine to the Royal Astronomical Society in 1821. Its purpose was to tabulate polynomials using a numerical method called the differences method. The Society approved the idea, and this in turn enabled him to get a grant of £1500 by the British Government in 1823.

Construction started on this machine, but it was not completed. Two things went wrong. One was that the internal friction and gearing available at the time were not good enough for the models to be completed - vibrations were a constant problem. The other was that he kept changing his mind about the design of the machine. By 1833, £17000 had been spent with no satisfactory result.

Analytical Engine

Between 1833 and 1842, Babbage tried again; this time, he tried to build a machine that would be programmable to do any kind of calculation, not just ones relating to polynomial equations. This was the Analytical Engine. The design was based on Joseph Marie Jacquard's sewing loom, which used punched cards to determine how a sewing design would be carried out. Babbage adapted this design so that it would create mathematical actions instead.

The Analytical Engine had input devices based on punched cards, as per Jacquard's design, an arithmetic processor that calculated numbers, a control unit that determined that the correct task was carried out, an output mechanism and a memory where numbers could be stored whilst waiting their turn to be processed. It was this device that was the world's first computer. A concrete design for this emerged by 1835; however, because of his failures involving the Difference Engine, the engine was never built. In 1842, following repeated failures to obtain funding from the First Lord of the Treasury, Babbage approached Sir Robert Peel for funding. Peel refused, and offered Babbage a knighthood instead. This was refused in turn by Babbage. Matters came to a halt at this point.

Babbage did receive noteworthy backing from one source. Lady Ada Lovelace became aware of Babbage's efforts and became very interested in them. She actively promoted the analytical engine, and wrote several programs in what would today be called assembler language for the analytical engine. Historians agree that these instructions make Ada Lovelace the world's first computer programmer.

Computing - Later Years

In 1855, a Swiss named George Schuetz successfully built a model of the Difference Engine. It had been based on a 1834 design by Babbage. Babbage was amongst those who inspected it and gave a positive opinion. In 1859, the British Government purchased one of these for use in the Registrar General's Office. The purchase had no effect on the refusals to build an analytical engine.

Partly through Babbage's efforts at gearmaking for these machines, the British had superior machinery for the next few decades, and this contributed to the superiority of the British navy in the first world war.

Promotion of Analytical Calculus

Babbage is remembered for other accomplishments as well. The promotion of analytical calculus is perhaps the foremost amongst them. In 1812, Babbage helped found the Analytical Society. The aim of this society, led by student George Woodhouse, was to promote Leibnizian, or analytical, calculus over the newtonian-style calculus then in use throughout the British Isles. Newton's calculus was clumsy, and was in use more for political reasons than practical. The Society included Sir John Herschel and George Peacock amongst its members.

In the years 1815-1817 he contributed three papers on the "Calculus of Functions" to the Philosophical Transactions, and in 1816 was made a fellow of the Royal Society.

Other accomplishments

From 1828 to 1839 Babbage was Lucasian professor of mathematics at Cambridge. He contributed largely to several scientific periodicals, and was instrumental in founding the Astronomical Society in 1820 and the Statistical Society in 1834. During the later years of his life he resided in London, devoting himself to the construction of machines capable of performing arithmetical and even algebraic calculations.

Charles Babbage also achieved notable results in cryptography. He broke Vigenère's autokey cipher as well as the much weaker cipher that is called Vigenère Cipher today. The autokey cipher was generally called "the undecipherable cipher", though due to popular confusion many thought that the weaker polyalphabetic cipher was the "undecipherable" one. Babbage's discovery was used to aid English military campaigns, and was not published until several years later; as a result credit for the development was instead given to Friedrich Kasiski[?], who made the same discovery some years after Babbage.

He only once endeavoured to enter public life, when, in 1832, he stood unsuccessfully for the borough of Finsbury.

See also

• History of computing
• Ada Byron, Countess of Lovelace, described and programmed the analytical engine

External links

• McTutor biography of Babbage (http://www-history.mcs.st-andrews.ac.uk/history/Mathematicians/Babbage)
• Science Museum's exhibit on the Difference engine (http://www.sciencemuseum.org.uk/on-line/babbage/index.asp)
• E-texts of some of Charles Babbage's works:
  • On The Economy Of Machinery And Manufactures (http://www.abacci.com/books/book.asp?bookID=1504)
  • Reflections on the Decline of Science in England (http://www.abacci.com/books/book.asp?bookID=1963)