Computing · 1622
Slide rule
Two sliding logarithmic scales that powered engineering for 350 years.
William Oughtred placed two logarithmic scales against each other so that multiplication became adding lengths. The slide rule designed bridges, aircraft and the Apollo spacecraft until pocket calculators displaced it in the 1970s.
What it built on 1
Related measurements
The dashed line marks when it first worked.
Computation per constant dollar, 1850-2006 Latest: 7.3B million units of computer power per 2006 $ (2003) Source: Nordhaus 2007, Two Centuries of Productivity Growth in Computing, J. Econ. Hist. 67(1), Table 6