From: Peter Stephenson <pws@ibmth.df.unipi.it>
Subject: Re: (urth) Terminus est--another military procurement fiasco?
Date: Tue, 20 Oct 1998 09:58:44 +0200

"Kevin J. Maroney" wrote:
> Think about the stroke involved in beheading a prisoner. The sword is
> raised overhead and brought down in a smooth circle. Gravity, not the
> centrifugal effect, is what moves the quicksilver. As the sword passes the
> point at which it is horizontal to the ground, the tip becomes much
> heavier, and gravity brings the mercury into the tip.

That can't be quite right, since until it's horizontal gravity is
keeping the mercury at the hilt end.  Long ago I used to play with
things where what I was later taught to call `inertia' (or, in a
rather supercilious physicist's tone, `so-called centrifugal force'
--- the superciliousness was implied rather than actually expressed,
you know how these things work) where a loose object would move to the
end of the stick by the time I'd got it horizontal.  I would contend
that if that *doesn't* happen here, the mercury is moving too slowly
to make it useful when cutting people's (such as supercilious
physicists') heads off.  The real question is the dynamics of the
mercury in the groove.  Also fairly long ago, I (or a brother) had a
mercury maze where you rolled a ball of mercury around.  I suppose
that in the sword it would be ball-like, too, so it would behave
better than, say, water.  So maybe it would work after all.  I've had
doubts, but I expect Wolfe as an engineer would know better than a
supercilious physicist.

> Thus, the lichtor can
> raise the sword slowly and bring it down very quickly.

That's what gravity's for in any case.  In the total process of
lifting and lowering through a full cycle, only the weight counts.
The theory is that the mercury gives it that last bit of oomph just
where it's a going through some stiff bits of bone and gristle in
someone's neck.  I'd love to see this demonstrated... err, maybe not
on a human.

> It's a ceremonial sword of office. Who other than the torturers would want it
> ?

Yes, unless some eccentric armiger had it made because he thought it
would be useful and found it wasn't.  (SDI?)

I can think of one use... classical art is full of pictures of Judith
about to cut off the head of Holofernes, or just after (but not
usually in the middle).  In particular, there's a statue by Donatello
in the Palazzo Vecchio in Florence with a particularly weedy Judith
waving an overgrown dagger at the massive trunk of Holofernes' neck,
and it all seems a little futile.  A decent carnifex' sword would
certainly help.

(There's another Judith and Holofernes by Artemisia Gentileschi, and
this time it's quite clear who's got the upper hand.  It's about to be
very, very messy.)

-- 
Peter Stephenson <pws@ibmth.df.unipi.it>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarotti 2, 56100 Pisa, Italy

*More Wolfe info & archive of this list at http://www.urth.net/urth/