@4stjack Yeah, the actual thing is more like "[Like I taught him how to make tea,] I want to teach him about the philosopher's stone," (or, according to our TL, "Well, I also want to teach you about philosopher's stone…") so it doesn't specify whether it's teaching about the history of it, how to use it, how to make it, or anything else. Changed the pronouns because it's narration… but the whole thing is kinda weird. I assume it's intentionally vague…? So we didn't want to make it sound more natural, by saying what it would be taught, because we didn't know for sure, and it could be misleading that way. But, yeah. Thank you, for pointing that out. Definitely a weird part.
(Though, it's worth mentioning that our TL at the time—we have a new one, for the chapters after this—wasn't very experienced, so it's definitely possible that it was a translation error, in the beginning. Unfortunately, the TL that did that chapter can't be asked for sure, because they've been on a hiatus, and will be for quite a while.)