Agree: https://en.wikipedia.org/wiki/August_Kekulé#Kekulé's_dream

(I had the impression from somewhere else that his "reverie or day-dream" might have instead been a pipe dream — as in the literal pipe dream (opium?). But I can now find nothing to substantiate this at all so, maybe just ignore.)

EDIT: perhaps I was reading too much into this page from the Golden Book of Chemistry: https://www.slideshare.net/slideshow/the-golden-book-of-chem...