## Colloquium: “350 Years of Service … and Then Pffft!”

Marshall University Math Colloquium

February 17, 2015

David Cusick

*Marshall University*

**Abstract**

After more than three centuries as a well-known calculation tool, the slide rule was eclipsed by electronic calculators in the 1970s. Based on the “common” (base 10) logarithm, this analog device was state-of-the-art before its popularity collapsed. The elementary slide rule aided the approximation of products, quotients, powers and roots. A variety of other models could handle more sophisticated functions. Some rules are still in regular use even at the present time. Virtual rules exist, and there are some “apps” for that. This talk will just touch the basic theory and a few examples. Logarithm laws are well represented. If time permits, we can see a photo gallery. Everything should be readily accessible to those who are at and above pre-calculus.