Concerning books: At least for books on magic, there seem to be constant revisions of spellbooks, so probably the newest editions would be harder to come by. A lot of magic seems to be trial and error, as evidenced by the additions Snape did to his own potions handbook as a pupil.

It's weird he didn't share that knowledge when he was potions teacher though.

[–] threelonmusketeers@sh.itjust.works 1 points 5 days ago* (last edited 5 days ago)

It's weird he didn't share that knowledge when he was potions teacher though.

I've always assumed that he did. Unlike Slughorn, Snape didn't teach out of the book, and always hand-wrote the potion instructions on the board. I assume that these instructions included his own additions and improvements that he had discovered over the years.

[–] blarghly@lemmy.world 4 points 1 week ago* (last edited 1 week ago)

Probably because the standard textbook formulae are good enough to teach the curriculum to the students, and trying to teach something extra complex to a bunch of 14 year olds for a marginal object-level improvement isn't worth it. Presumably potions class doesn't teach you specific potions formulae, but rather teaches you the techniques and underlying concepts of potions so you can go to potions college with a firm grasp of the fundamentals.