De Prony and Human Computing

In 1791, Gaspard de Prony organised the computation of logarithm and trigonometric tables to 14–25 decimal places — a project employing 80 people as 'computers.' Following Adam Smith's principles of division of labour, de Prony split the work: top mathematicians designed the formulas, middle-tier workers set up the differences, and low-skill workers (including former hairdressers, unemployed after the fashion for wigs ended with the Revolution) did the arithmetic. This inspired Babbage to design the Difference Engine — to replace human computers with machine precision.