The protractor and the Bunsen burner. Playing the recorder in music class. Drawing arcs and circles with a compass in geometry. These tools of the education trade become part of our lives for a ...

Used by engineers for centuries, they were displaced by pocket calculators and all but forgotten until Mr. Shawlee created a subculture of obsessives and cornered the market. By Alex Traub For about ...

A regular slide rule takes advantage of the fact that you can multiply and divide by adding logarithms. Imagine having two rulers marked in inches or centimeters — it doesn’t matter (see the adjoining ...