1600-1699

The slide rule is a “mechanical analog computer (Wikipedia)” meaning that it is essentially a calculator. Before the creation of the electronic calculator, the slide rule was the easiest way to calculate the answers to almost all difficult computations and was created to do so. The slide rule was very successful because it made human computers jobs much easier and more accurate. The slide rule was commonly used for calculating multiplication, division, roots, squares, logarithms and trigonometry. The slide rule contains many scales that are logarithmic and these essentially convert the complex functions it can do into basic addition. Oddly enough the slide rule is not used for true addition and subtraction.

The slide rule was created by William Oughtred with the help of others in the 17th century. However Oughtred did not invent the logarithms they were invented by John Naiper.

The slide rule is operated by moving scales next to each other so that specific points line up and then reading the slide rule if used perfectly would always yield almost perfect results consistently however reading the slide rule requires estimation of the numbers being calculated. In addition when calculating large numbers even slightly altering the position of one of the scales can significantly change the outcome of the function. These possible human errors were the main reasons why human computers were replaced with electronic computers. Bibliography "Basic Slide Rule Instructions." //Basic Slide Rule Instructions//. N.p., n.d. Web. 24 Sept. 2012. <[]>. "Eric's Slide Rule Site." //Eric's Slide Rule Site//. N.p., n.d. Web. 24 Sept. 2012. <[]>. "Slide Rule." //Wikipedia//. Wikimedia Foundation, 18 Sept. 2012. Web. 24 Sept. 2012. <[]>.