Found this at a yard sale but I have no idea what it is. Thoughts?

For many of us, history is something that we took in school and we probably forgot more about what we learned in the class than what we remembered. It may not be the favorite subject for all of us, but there are some interesting things that can be learned from it.

That includes what we have in this interesting picture. It is something out of history that was used by millions of people but is not necessarily something that is recognized today. In fact, we would venture to say that most people would not know what it is.