In the course of my researches for a new campaign book, I have run across
something the Celts and/or Picts of east and southern Scotland used to use in
their fortification: Vitrification.

I think this would be a *very* cool technique for Elves to use, in order to
give them a unique flavor to their castles. Note that this technique would be
rather expensive in terms of elves having to use such huge quantities of dead
wood from the forest. But hey, I most campaigns, elves hardly ever build
castles anyway. The few they do shell out for can and should be "fancy".

The creation of a "vitrified", or glass tower was, in my view a brilliant
invention. It was done this way: A fortification was built of stone and
around it placed a latticework of timber. The timber was fired and the heat
fused the stone (sandstone?) creating a glassy, unclimbable surface.

In reality, the walls of such a fort would be rather low at about 20-30 feet.
However, Celt legend has it that forts of the Otherworld often were castles
and towers of glass which were much taller. It is thought that Glastonbury
itself means "fort of glass", although no glass castles were found south of
what is now Scotland. But I better stop myself right now before I go off into
that tangent. :)

Later!
Dustin Evermore