Robert you may be right about the dripping water.  How one would have  used the gas created I do not know but that is the genius in simple processes.
http://en.wikipedia.org/wiki/Acetylene
It has just come to me like a bolt of lightening.  They make licquid Acetylene then use a low pressure primus stove type of torch simple. How dumb am I 

 .  The sword could be 19th century.  Skilled work 

 .