Before I went to seminary, I was going to be a mathematician. In fact I spent three years as a teaching assistant in the math department at the University of Wisconsin-Madison. In those days I had a string of calculators, which were then a fairly new item. Yeah, in high school we'd learned to use slide rules. But calculators had rendered slide rules obsolete... hadn't they?

It was only many years later that I began running across old slide rules at garage sales, at St. Vincent's, in antique malls. I still had an old circular Pickett from my high school days. I've accumulated a small but nice collection. My favorite is a Keuffel & Esser Log Log Duplex Decitrig, model 4081-3, from back around 1940. The 20 scales are machine ruled on celluloid, over a core of mahogany.