<P> In 1895, a Japanese firm, Hemmi, started to make slide rules from bamboo, which had the advantages of being dimensionally stable, strong, and naturally self - lubricating . These bamboo slide rules were introduced in Sweden in September, 1933, and probably only a little earlier in Germany . Scales were made of celluloid, plastic, or painted aluminium . Later cursors were acrylics or polycarbonates sliding on Teflon bearings . </P> <P> All premium slide rules had numbers and scales engraved, and then filled with paint or other resin . Painted or imprinted slide rules were viewed as inferior because the markings could wear off . Nevertheless, Pickett, probably America's most successful slide rule company, made all printed scales . Premium slide rules included clever catches so the rule would not fall apart by accident, and bumpers to protect the scales and cursor from rubbing on tabletops . The recommended cleaning method for engraved markings is to scrub lightly with steel - wool . For painted slide rules, use diluted commercial window - cleaning fluid and a soft cloth . </P> <P> The slide rule was invented around 1620--1630, shortly after John Napier's publication of the concept of the logarithm . In 1620 Edmund Gunter of Oxford developed a calculating device with a single logarithmic scale; with additional measuring tools it could be used to multiply and divide . In c. 1622, William Oughtred of Cambridge combined two handheld Gunter rules to make a device that is recognizably the modern slide rule . Like his contemporary at Cambridge, Isaac Newton, Oughtred taught his ideas privately to his students . Also like Newton, he became involved in a vitriolic controversy over priority, with his one - time student Richard Delamain and the prior claims of Wingate . Oughtred's ideas were only made public in publications of his student William Forster in 1632 and 1653 . </P> <P> In 1677, Henry Coggeshall created a two - foot folding rule for timber measure, called the Coggeshall slide rule, expanding the slide rule's use beyond mathematical inquiry . </P>

Who invented slide rule and in what year