A.1 A Brief Time Line

  • c.1590 – Galileo Galilei, Italy, uses a sector to calculate squares, reciprocals and tangents of numbers. From the Oughtred Society publication, All About Slide Rules: “Galileo’s design of the sector as a mathematical tool can be seen as the moment when calculation aids cease to be based upon counting and instead exploit the deeper relationships among numbers.”

  • 1614 – John Napier, Scotland, publishes Canon of Logarithms

  • 1617 – John Napier, Scotland, and Henry Briggs, England, publish Logarithmorum Chilias Prima (“The First Thousand Logarithms”), which gave a brief account of logarithms and a table for the first 1000 integers, calculated to the 14th decimal place.

  • 1620 – Edmund Gunter, England, invents the straight logarithmic scale, used through the aid of “dividers” (compasses) to add logarithms to perform calculations

  • 1624 – Edmund Wingate, Paris, publishes description of Gunter’s logarithmic scale; English translation (1628) contains sector engraved with logarithmic Gunter’s scale

  • 1624 – William Oughtred, England, arranges two Gunter scales to slide along each other, kept together by hand – the first “sliding” rule

  • 1632 – William Oughtred, England, produces “Circles of Proportion”, a single circular sliding rule with logarithmic scales

  • 1675 – Sir Isaac Newton, England, solves the cubic equation using three parallel log scales; also first suggested using an indicator (or, “cursor”) about this time

  • 1677 – Henry Coggeshall, England, puts logarithmic scaled slide in two-foot folding ruler, adapted for timber measure; first “standard” rule of its kind, a type that lasted for about 200 years

  • 1722 – John Warner, England, first uses square and cube scales

  • 1775 – Thomas Everard, England, created inverted log scale, and “gauging”

  • 1775 – Matthew Boulton, England, and James Watt, Scotland, design an engineering slide rule, the Soho slide rule, for the design of their steam engine

  • 1779 – Boulton and Watt improve the accuracy of their rule; becomes a standard for the engineering profession

  • 1800-1810 – Joshua Routledge, England, invents the Engineer’s Rule, combining a 12-inch brass slide containing the logarithmic scales with an ordinary 2-foot folded ruler to which was added a table of commonly used gauge points; extending the brass slide can create a standard “yard” stick.

  • 1815 – Peter Roget, England, (yes, of Thesaurus fame!) invents the Log-Log scale

  • 1843 – Aaron Palmer, USA, manufactures and introduces a circular logarithmic “Computing Scale” to the U.S. market; seen mostly as a curiosity, it was sold across the U.S. and Europe until the 1870s.

  • 1850 – Lieutenant Amédée Mannheim, France, presents his form of the slide rule, with the modern arrangement of scales (A, B, C, D); added cursor to his rule in 1851

  • 1859 – Amédée Mannheim, France, credited with the invention of first modern slide rule

  • 1878 – George Fuller, Ireland, invents the Fuller cylindrical long-scale calculator

  • 1881 – Edwin Thacher, USA, invents the Thacher long-scale calculator

  • 1890 – a survey showed that England, France and Germany were the only manufacturers of slide rules at this time

  • 1891 – William Cox, England, patents concept for the duplex (double-sided) slide rule, assigns patent to K&E in USA; K&E becomes first major slide rule manufacturer in USA

  • 1894 – slide rule production begins in Japan with formation of Sun/Hemmi

  • 1900 – folded scales (e.g., CF, DF) introduced about this time

  • 1902 – Max Rietz, Germany, proposes his new arrangement of scales which becomes a new standard; this arrangement includes the K and L scales for cubes and logs

  • 1909 – segmented (3 sections) Log-Log scales put on K&E rules

  • 1923 – Olin Parsons, USA, patents (applied for in 1919) special scales for finding hypotenuse of right triangle; similar scales later introduced on certain Sun-Hemmi rules (P, Q, Q’ scales) in Japan

  • 1925 – Max Rietz, Germany, adds reciprocal scales and small-angle scales to the Rietz arrangement

  • 1924-1928 – Albert Puchstein, USA, and Mendell Weinbach, USA, independently invent Log-Log Vector scale sets for evaluating hyperbolic functions with complex arguments in Cartesian and/or polar form

  • 1929 – Sadatoshi Betsumiya and Jisuke Miyazaki, Japan, invent the P and Q scales used on Hemmi rules for adding and subtracting numbers in quadruature

  • 1934 – Alwin Walther, Germany, at the Technische Hochschule Darmstadt, modified the Rietz system for the needs of engineers, establishing the System Darmstadt

  • 1937 – Patent issued for \(G_\theta\) scale on Hemmi rules, invented by Hisashi Okura, Japan, for finding values of hyperbolic functions

  • 1947 – James Bland, USA, patents set of scales, relating the LL0 scale (and all other scales on the rule) with the C/D scales, and grouping LLx and LL0x scales together for more easily calculating hyperbolic functions.

  • 1972 – Hewlett-Packard introduces the first “pocketable” scientific calculator, HP-3 ($395)

  • 1972-75 – development of Hewlett-Packard HP-35 and Texas Instruments SR-50 calculators drives down the cost of these devices ($100-300)

  • 1974 – first programmable scientific pocket calculator HP 65, with register and program memory on magnetic strips ($795)

  • 1975 – slide rule production begins to cease in Japan and England.

  • 1976 – Texas Instruments introduces the single chip TI-30 scientific slide rule calculator for $24.95 USD on June 13, below the cost of a comparable slide rule. The last slide rule to be manufactured by K&E, in July, is donated to the Smithsonian Institution in Washington, D.C.; Pickett ends slide rule production one month later in August.

  • 1977 – Faber-Castell curtails slide rule production.

  • 1978 – Aristo and Nestler each end slide rule production by this year.