Logarithmic Slide Rule

Let’s assume that you haven’t ever considered how to make a slide rule.  We have a machine at the Museum that did make them. It worked for the Keuffel & Esser Corporation in Hoboken, New Jersey.  K&E was founded in 1867 and started making slide rules in 1891, which they did until 1975.

High quality slide rules, like K&E’s, are very precisely graduated.  That was our machine’s job: scribing the lines on the rules. 

The locations of the rule’s lines represent numerical quantities.  They are laid out in logarithmic order.  The result of adding two logarithmic numbers is that they multiply each other (for instance.) 

If you’d like to know more about slide rules, there’s an article on the subject at Wikipedia  that will be much more helpful than we can be.

Our machine was given to the museum by Theo Alteneder of Philadelphia.  It was restored by Michael P. O’Leary, who wrote about it for the Oughtred Society.

The slide rule machine is part of our Behind The Scenes Tour, so if you’d like to see it in person, please sign up for the tour!