In the first chapter you were able to buy the diagrams for sword runes from the blacksmith. I was pretty poor then though and decided to not buy any. I'm in chapter 2 now and need some runes but none of the vendors sell the diagrams for them. Is there a vendor I'm missing somewhere? Or is it possible to go back to Flotsam?

Have u looked at what the crafters are selling as well? I think the crafters sell both runes and rune diagrams.

Yep several times, unless I'm missing one that isn't labelled or isn't in the main camp. There's also the 2 vendors out near the brothel but neither are crafters or sell them.

You picked Roche huh? Yeah I was talking about the Vergen crafters... Haggard, the assistant of the blacksmith... He is on the other side of the damn mist...

Sorry, no idea.

Ya I picked Roche. Hopefully someone else ran into this problem and can give me some insight. I'm trying to decide now whether it is worth it to buy those diagrams and replay the last couple of hours or just continue and hopefully find a vendor that sells them. I don't want to have missed out on those recipes for the rest of the game though.. And my new silver sword could really use some runes.

No, no one in or around Henselt's camp sells rune diagrams, sadly. You can get them again in Act III.