Was the sky blue back then, too?

The funniest was in ninth grade physical science. We had an experiment where we burned substances and identified them by the color of the flame. Both my lab partner and I were color blind. We did okay on most, but there was one substance that I could not see any color on - it was a “clear” flame. I’m serious - there was a thermal distortion, but I could barely tell the flame was there at all. I think we asked our neighbors on that one.