Liavan accompanied her words with a series of gestures she hadn't known that she knew and felt the power move into the spell like a rumble in the earth rather than the usual ring of a small bell.

That's more than a little alarming, when all of her previously described magic-working appeared to have been the result of dilligent study and meticulous experimentation.

Also I am most curious at the cosmology behind what the Withemistresses (are there Withemasters, too?) do. <waits sort of patiently to see what turns up>

Possible nit:
"These will suppress a cough, so you shouldn't use them if you're coughing or spitting out gunk."
Possibly "or" there would make more sense as "and", given the two types of cough remedy?