Calculator History

For many decades before the advent of calculators and computers the slide rule was the standard for scientific and engineering calculations. Most people learned to use a slide rule in high school science classes. Engineers were known for walking around with a slide rule hanging in a leather holster on their belt. In university I had a very good quality precision slide rule like the one below (Geotec Versalog II). I received it as an award for being the top student in first year engineering.
When I was in first year university one of the other students got the first calculator we had ever seen. Every one crowded around to see this new marvel of technology - a pocket sized four function calculator! (It doesn't take much to get engineers excited.) I believe he paid several hundred dollars. Then a while later I bought my first calculator, a Sears Digimatic 8 like the one below for $89. This made an amazing difference for homework but I still had to rely on my trusty slide rule for many calculations.

After the first pocket sized calculators came out there was rapid advancement with more and more functions resulting in the availability of scientific calculators. By the end of second year university I bought a Hewlett Packard HP 35 calculator like the one below for $255. The HP 35 was the world's first pocket scientific calculator and used Reverse Polish Notation. This was an engineer's dream. Unfortunately after using this all through third year it malfunctioned and wasn't repaired on warranty in time for final exams. I had to go back to my slide rule for my exams (I still did OK though.)

So ends my second chapter in the history of technology. Stay tuned for further episodes.