You've probably got it exactly. I just checked and you are correct, over the 1800s there was a Weekly and a Monthly-- distinct publications but each with "Harper's" in the title so as to confuse T206collector (but not me, I know along of course
).
My technique for watching Jeopardy is, when someone watching with you says the answer, repeat it right after them. That way people think you knew the answer all along, but just weren't quite quick enough in saying it.