At the start of the book (no previous context) the teacher asks this question:
「ではみなさんは、そういうふうに川だといわれたり、乳の流れたあとだといわれたりしていたこのぼんやりと白いものがほんとうはなにかご承知ですか。」
Well everyone, this vague white thing which has been called a river and has been called a trail of flowing milk, do you know what it really is ?
I'm unsure about how the ending of this sentence works (italics) but I'll ask a separate question for that.
For this question, I don't understand the meaning of そういうふうに. Literally I think it means "in that kind of way" but I can't make such a translation work in this sentence.