(urth) Fuligin?

[David Duffy]

On Thu, 17 Jul 2014, David Stockhoff wrote:

> It's actually amazing that no one has tried to make one, at least that I
> have heard of. I wonder what technical challenges would be involved.

http://www.swordforum.com/forums/showthread.php?102296-Sword-with-sliding-weight

"...and from his huge sword, which had a remarkable accessory in the shape 
of an iron ball that slid along the back of the blade to give an 
additional weight to every cut"