Charles Babbage was born on December 26, 1791 in Devonshire, UK, to a well-to-do banker. He attended Trinity College, Cambridge, and obtained an MA degree in 1817. He was appointed to the Lucasian Chair of Mathematics at Cambridge, the chair Newton once occupied. He was a profound thinker who was way ahead of his times. One of his major shortcomings was his inability to convincingly present his ideas in a simple enough language and convey their importance to his sponsors with the result that he could not obtain sufficient funding to complete both the mechanical calculating devices he conceptualized: the difference engine and the analytical engine.

Babbage was fascinated by machines and measurements. He was in his prime during the industrial revolution and was seriously interested in the railways, which started expanding in Britain in 1840. In 1838 he invented the cowcatcher used in engines. He conducted research on safety and efficiency of railway tracks and supported the use of broad gauge, which was later adopted as the standard gauge in UK. While attending operas he was more fascinated by the mechanisms used in changing scenes and often went backstage to observe their working rather than enjoying the opera. One of his finest works was ‘On the Economy of Manufacturing’, published in 1832. In this book he reported some pioneering work on improving the efficiency of manufacturing processes ranging from needle making to printing machines. The genesis of this work was the difficulty he was experiencing in building the difference engine due to the high machining precision needed which was difficult to achieve with the existing technology.

He was also obsessed with measurements. He tried to measure everything from heart beats of pigs to the proportion of sexes among the poultry. He proposed to the Smithsonian Institution that a table of such data should be prepared for all properties that can be expressed by numbers in various sciences and arts. His conviction of the need of detailed quantification led him to start the Statistical Society of London in 1834. He also founded the British Association for the Advancement of Science in 1831.

The innovations for which he is remembered are his designing and building (in a semi-finished state) what he called the difference engine and later conceptualizing the Analytical Engine – the forerunner of the modern stored program computer. The genesis of the difference engine was the need for accurate trigonometric and other tables to aid navigation by ships in the 1800s. The idea of difference tables was proposed by Newton and was a powerful method for calculating values of functions representable as polynomials. In 1801 Proney and a team of computing assistants constructed manually a very large set of tables known as the French Grand Tables using the method of differences. As it was done manually and the results also noted by hand they were error prone.

Babbage was an accomplished mathematician and also an excellent mechanical engineer. He was obsessed with the idea of removing drudgery of calculations and dreamed of building machines to compute tables similar to the French Grand Tables. He spent considerable time in acquainting himself with a variety of mechanical tools and how to design and build them. He was thus able to design the mechanisms himself and delegated the responsibility of building parts to technicians. This required detailed drawings and instructions to be given to technicians. Babbage has written in his memoirs that “The complicated relations which then arose amongst the various parts of the machinery would have baffled the most tenacious memory. I overcame that difficulty by improving and extending a language of signs, the Mechanical Notation, which in 1826 I had explained in a paper printed in the ‘Phil.Tran’. By such means I succeeded in mastering trains of investigation so vast in extent that no length of years ever allotted to one individual could otherwise have enabled me to control”. Babbage realised that both correctness in calculation and in printing were essential. Thus he began building a machine which would not only compute accurately functions approximated by polynomials but also print them. Babbage called this the Difference Engine to compute functions using difference tables. The main advantage of using difference tables is that it does not need multiplication and division but only addition which is easier to mechanise. He also proposed use of pipelining in addition to expedite calculation. His original design of the difference engine was to have a precision of 6 decimal digits and use up to second-order difference. He got a grant from the British Government to embark on this project. The cost steadily escalated and ultimately he spent around 17000 British pounds of Government money and a similar amount from his pocket. He however was not able to complete the project as mechanical engineering practice at that time had not progressed enough to produce, and duplicate in hundreds, precision parts of intricate shapes required by the engine.

In addition to this difficulty he also had to contend with the problem of training and retaining skilled technicians to work on his project. To quote from his memoirs. “The railroad mania withdrew from other pursuits the most intellectual and skillful draftsmen. One who had for some years been my chief assistant was tempted by an offer so advantageous that in justice to his own family he could scarcely have declined it”. Inspite of the fact that the engine was not completed, Babbage persisted with his mission and planned a machine which could support 20 decimal digits and sixth-order differences. The British Government decided in 1842, based on a report by Sir George Airy, to discontinue funding the project. Inspite of this setback Babbage persisted with his efforts to make a more versatile computing machine to be called the analytical engine, which he had conceived in 1833. This was indeed way ahead of its time in concept. In the Classics section in this issue the details of this machine as perceived by Babbage are reproduced in his own words. Babbage passed away in 1871, the world not knowing that he was a genius but branding him as an eccentric scientist with hare-brained schemes.

Address for Correspondence
V Rajaraman
SERC,
Indian Institute of Science
Bangalore 560 012, India.