[Harp-L] Reed Arc?

["Blake Taylor" <taylorb@xxxxxxxxxxxxxxxx>]

I've heard about reed arcing, and I think a fellow harper showed me the
inside of his harp with arced reeds before, though it was a late night
and I'm not positive.

Anyway, as a struggling novice at harp maintenance, what exactly is harp
arcing, and how is it accomplished, and for what purpose?

I think I get embossing, though I'm not entirely sure.

Oh, and is it a common occurance for you to tune a reed that has gone
flat, have it sound fine, put the harp back together again, play it -
still sounds fine - and then the next day be flat again?  What gives
here?

Thanks in advance.......

 - Blake