Thanks for your comment. Yes, minerals in Gilbert’s box were unharmful unless they came in direct contact with blood or inhaled. At that time, every chemistry set contained potentially harmful elements for a child, but probably the idea of uranium was of some concern for parents (or just an excuse, since the set wasn’t cheap at all). I was born in the late ’70s, and my first chemical set had potentially toxic elements that most six-year-old boys today don’t even know exist.

Wow! Did you build your own cloud chamber? I never tried anything even close to that. That’s probably why I ended up in the humanities. LOL