Hemmasara

Created sometime in the Dark Ages by Sir Bedevere of the round table, the logic behind the detection of witches is as follows-

• Q- What do you do with Witches?

A- BURN THEM!!

• Q- What else do you burn apart from witches?

A- MORE WITCHES!! ... wood?

• Q- So, why do witches burn?

A- B..Because they're made of wood?

• Q- So, how do we tell if she is made of wood?

A- Build a bridge out of her!

• Q- Ahh, but can you not also build bridges out of stone?

A- Oh yeah, oh yeah, you can..

• Q- Does wood sink in water?

A- No, no it doesn't! Throw her into the pond!

• Q- No, what else floats in water?

A- Bread! Apples! Very small rocks! Cider! Gravy! Cherries! Mud! Churches! Lead!

• King Arthur - A duck.
• GASP

So, through this logic, if she weighs the same as a duck, she's made of wood, and therefore a witch.