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Definition: Babbage, Charles from The Columbia Encyclopedia

(băb'ĭj), 1792–1871, English mathematician and inventor. He devoted most of his life and expended much of his private fortune and a government subsidy in an attempt to perfect a mechanical calculating machine that foreshadowed present-day machines. He was a founder of the Royal Astronomical Society. He wrote Tables of Logarithms (1827) and an autobiography (1864).

  • See biographies by M. Moseley (1970) and D. Halacy (1970).

Summary Article: Babbage, Charles (1792-1871)
from The Hutchinson Dictionary of Scientific Biography

Place: United Kingdom, England

Subject: biography, computing, maths and statistics

English mathematician, one of the greatest pioneers of mechanical computation.

Babbage was born in Totnes, Devon, on 26 December 1792. His father was a banker who left him a large inheritance, and throughout his life Babbage was financially secure. He developed an interest in mathematics as a young boy and in 1810 went to Cambridge University to study mathematics. There he became a close friend of the future astronomer, John Herschel, and, convincing himself that Herschel would be placed top in the honours examinations, chose not to be placed second and took only a pass degree, in 1814. While at Cambridge Babbage, Herschel, and other undergraduates founded the Analytical Society, and it was in the society's rooms one evening, that Babbage is recorded as saying (while looking over some error-filled logarithm tables) ‘I am thinking that all these mathematical tables might be calculated by machinery’.

The year after he left Cambridge, Babbage wrote three papers on ‘The calculus of functions’ for publication by the Royal Society and in the following year, 1816, he was elected a fellow of the society. Some time later, while making a tour of France, he examined the famous French logarithms which had been recently calculated and which were the most accurate tables then known. They had, however, required the combined efforts of nearly a hundred clerks and mathematicians. Mathematical tables of all kinds, including logarithmic tables, were of great use for astronomical, commercial, and especially, navigational purposes. On his return to London, therefore, Babbage set about developing his ideas for a cheaper and more accurate method of producing tables by mechanical computation and automatic printing.

By 1822 he had ready a small calculating machine able to compute squares and the values of quadratic functions. It worked on the method of differences, an example of which involves subtracting one square from the preceding one to obtain a first difference, and then the first difference from the next above it to obtain a second difference, which is always two.

By working backwards, adding the second difference to the first difference, and then adding the higher of the squares used in the subtraction that had produced the first difference, the next square is always obtained. Using second-order differences of this kind Babbage's first machine could produce figures to six places of decimals.

With the backing of the Royal Society, Babbage was able to persuade the government to support his work to devise a much larger difference engine to calculate navigational and other tables. He was elected to the Lucasian chair of mathematics at Cambridge in 1826, a post he held until 1835, but he continued to live in London and did not perform the usual professorial duties of lecturing and teaching. He devoted himself entirely to his machine, which he proposed to make work to sixth-order differences and 20 places of decimals. The construction of the large difference engine was a laborious and lengthy operation. New tools had to be designed to previously unknown tolerances, many of them being made for Babbage by the great pioneer of precision engineering, Joseph Whitworth. The project cost the government £20,000, but it was eventually abandoned, partly because of problems of friction (the arch-enemy of the engineer), partly because of personality clashes, but chiefly because before it was completed Babbage had hit upon a better idea.

That idea was the analytical engine. The difference engine could perform only one function, once it was set up. The analytical engine was intended to perform many functions; it was to store numbers and be capable of working to a program. In order to achieve this, Babbage borrowed the idea of using punched cards from the French engineer Joseph Jacquard, who had invented such cards in 1801 to program carpetmaking looms to weave a pattern. Babbage's machine, begun in 1833, was to have a mill to carry out arithmetical operations, a memory unit to store 1,000 numbers of 50 digits, and the program cards, linked together to direct the machine. The cards were of three kinds: those to supply the store with numbers, those to transfer numbers from mill to store or store to mill, and those to direct the four basic arithmetical operations. In order to unite the programs for his cards Babbage devised a new mathematical notation.

Babbage's machine had not been completed by the time of his death, on 18 October 1871. And although his son H P Babbage carried on the enterprise 1880-1910, the fact is that its complexity was beyond the engineering expertise of the day and its very conception beyond the grasp of society to spend the amount of time and money required to build it. Nevertheless, it was Babbage's machine - although, being decimal not binary and requiring the use of wheels, not strictly digital in the modern sense - which Howard Aiken used more than 70 years after Babbage's death as the basis for his development of the Harvard Mark I Calculator.

Babbage was a true representative of the Victorian age, the age of the steam engine and the industrial revolution. He wished to harness science to the practical improvement of society. Hence, dissatisfied by the practical usefulness of the Royal Society, he had a hand in founding the Astronomical Society (1820), the British Association for the Advancement of Science (1831), and the Statistical Society of London (1834). The same passion for improvement led him to investigate the operation of the Post Office and, on finding that most of its costs derived from the handling of letters rather than their transport, to recommend (what Rowland Hill introduced as the penny post) that it should simplify its procedure by introducing a single rate. But his greatest idea, the mechanical computation of tables, remained ahead of the practical possibilities of his time.

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