You tickled my memories about slide rules. As a college freshman I sweated to buy the gem of slide rules a K&E log-log duplex ivory over mahogany. It is a jewel I still have it. After WWII on the G.I. Bill I got a Pickett & Eckel magnesium vector log-log which was king of the rules at the time and which I still have. I picked up all kinds of rules along the way, small, large and circular. The advancement of handheld calculators really shelved the slide rules and hid the history. I remember an engineering prof telling the class that the most valuable things to an engineer were his slide rule and drafting set. Things will and do change.
Do you still know how to use the slide ruler? I picked one up at a thrift store in the 80’s and tried to grasp how to work it, but I couldn’t. We of course used calculators to do logarithms at that point. My college library at the time still had these HUGE volumes of logarithms, but they were just collecting dust. Along with the volumes of random numbers.
Since I was going to use it the rest of my life, I spent a little extra money to get a metal Pickett sliderule for part of 9th grade algebra.
Who could have imagined the changes that were coming? Some did, not me as a 9th grader. I bought a Casio electronic calculator only 5 years later for $200 IIRC.
Still have it. I keep it safe in my sock drawer.