The thing is, the older our family heirlooms are the likelier we are NOT to know what the heck it was supposed to be. While the slide rule is probably still fairly recognizable to my generation (I'm 42) and older. My kids would have NO idea what it was or how to use it. My grandfather, Howard Dunaway, was an electrical engineer. I wonder how many of today's EE's still use a slide rule - my guess is none!
While transcribing my grandmother's diary, I noticed she frequently referenced going to the show because it was "bank nite". What the heck was that? Well, luckily it was not hard to find out; it was a practice unique to the 1930's to entice people to spend money at the movies. A drawing for some cash - $90 was the pot one night by GP's went - was given out about once a week. They didn't win, but it did keep them going back.