On Jun 13, 10:52 pm, Rip wrote:
Dan wrote:

...

The one demonstration he did that I wish I knew how he did it was when
he poured a pitcher of a clear liquid into another clear liquid and they
both suddenly went black in the middle of the pour.

...

Google on "clock reaction".
Rip

Ah hah. That's it!

The reaction has been used since before
the Hellenistic Age. It was referred to by Aristotle
in his treaty on Physics, who may well have taught
the process to his most famous student, Alexander
of Macedon, who later used it to great advantage.

Alexander's father, Philip had amassed the largest
army the Mediterranean world had ever known
but had done little to advance the art of war in
terms of tactics. The standard formation was the
phalanx, several rows of spearmen who would
advance en masse usually against a similarly
arrayed enemy. As it was to be a thousand years
or so before the invention of ether the longbow
or the stirrup, neither was particularly effective and
Philip had eschewed both excepting for scouts
and couriers. And so whatever army had the
widest phalanx of sufficient depth could gain great
advantage over their enemy, by outflanking them.

The problem was that Philip's army was so large
that the phalanx was so wide that there was no
way to coordinate their advance. Alexander
solved this problem using what is now known
as the 'clock reaction.'

When the time neared for the attack to begin
Alexander would have the solution prepared
then cloth rags would be immersed in it and
several messengers, each with one of these
bands tied about their arm would leave to
take up positions at regular intervals along
the phalanx. As the armbands had all been
wetted with the same solution, they all
turned black simultaneously and that was
the signal used to coordinate the attack.

And now you know the story of
Alexander's Rag Time Band.

--

FF