Babbage and the Automation of Table making

History of Table Making

• 1766 - British govt sanctioned the Royal Astronomer (Nevil Maskelyne) to produce new tables, the Nautical Almanac • Known to the common man as the Seaman’s Bible, the Nautical Almanac was one of the first publications to be “outsourced”

Seaman’s Bible

• Computed by freelance “computers”, the Seaman’s Bible was produced by having each calculation produced by independent

computers

, and checked by a third “

comparator”.

• Many of the computers who produced the first copies of SB were retired clerks or clergy

Babbage at Cambridge

• Charles Babbage went to Trinity College, Cambridge in 1810, and soon realized that he knew more mathematics than most of his tutors • In response to the inadequacy of math training at Cambridge, he founded the Analytical Society • He was elected to the Royal Society at age 25

Babbage in Paris

• Babbage made several trips to Paris in 1819 to meet with eminent mathematicians of the day (Laplace, Fourier) • He learned of the table-making project organized by Baron Gaspard de Prony. • This project would show Babbage a vision that would determine the future course of his life.

Tables by DuProny

• In 1790, De Prony was appointed head of the Bureau du Cadastre, the French ordnance survey office. • The introduction of the new metric system required a complete new set of decimal tables, the Tables du Cadastre. • It was by far the largest table-making project the world had ever known, and de Prony decided to organize it much as one would organize a factory.

Manufacturing Logarithms

• De Prony took as his starting point the most famous economics text of his day, Adam Smith's

Wealth of Nations,

published in 1776. • In

Wealth of Nations,

Smith advocated the principle of division of labor (illustrated by means of an imaginary pin-making factory). If a worker specialized, the output would be vastly improved. • De Prony’s insight was to apply the same method to the immense work with which he had been burdened, and to

“manufacture logarithms as one would manufactures pins”.

The Difference Engine

• Babbage named his machine a “Difference Engine” since it would use the same

method of differences

, first proposed by Newton • In the 30 yrs between the De Prony project and Babbage, best practice in factories had itself moved on, and a new age of mass-production machinery was beginning to dawn. • The laborers in Adam Smith's imaginary pin-making factory would soon be replaced by a pin-making machine . Babbage decided that rather than emulate DeProny's labor-intensive and expensive manual table making organization, he would ride the wave of the emerging mass-production technology and invent a machine for making tables .

Difference Engines

• The first mechanical device to use the method of differences was conceived in 1786 by J. H. Mueller. It was never built.

• Difference engines were forgotten and then rediscovered in 1822 by Babbage. • This machine used the decimal numbers system and was powered by cranking a handle. • The British government first financed the project but then later cut off support. Babbage went on to design his much more general analytical engine but later returned and produced an improved design (his "Difference Engine No. 2")

Building the Difference Engine

• Babbage faced several problems in the construction of his machine – Design the mechanics of the machine – Develop the technology to build it – Find $$ to pay for the project • Between 1820-1830 Babbage had received over ₤17,000 (today’s equivalent of nearly $1 million)

Analytic Engine

• In 1842 Babbage applied to the Prime Minister (Duke of Wellington), for ₤ ₤ to complete the project • When requesting the funds he made the (fatal) mistake of mentioning that he had devised a “new machine” the Analytic Engine • The new “Engine” would be a multipurpose device

Data Processing in the 19

th

Century

• Banker’s Clearing House – Processed $250 billion in 1839 • Central Telegraph Office – 4,500 clerks – 150,00 telegraphs each day • Prudential Insurance Company