RE: Variable Capacitance and Inductance

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "David Thomson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org>

Hi Malcolm,

>He doesn't always, and if there is any doubt about that I would be happy to
bring his Guide in and quote the page in questiuon.

I would prefer if you did use exact quotes.  It makes it easier to carry on
a focused discussion.

>> Richard Hull notes these daily changes, too, as in his comment of Tesla's
November 7 entry.

>Yes. But he also noted that on one occasion at least, Tesla claimed some
massive increase in capacitance with a relatively tiny increase in height
(which he vehemently took issue with).

Richard Hull is an accomplished Tesla coil researcher of his own good works.
But I must offer my criticism of his book on Tesla's notes for his
unqualified opinions regarding Tesla's measurements.  Richard Hull does not
offer data to back up his opinions; Tesla does.  Until Richard actually
takes measurements under the same conditions as Tesla, his baseless opinions
cannot be used for scientific inquiry.

It reminds me of my ninth grade science teacher... We came to an experiment
in our manual where a ping pong ball was placed in an upside down funnel and
we had to blow into the funnel while releasing the ball.  The teacher said
there was no point in doing the experiment since it was obvious the ball
would simply fall to the floor.  Being of an inquisitive mind, I suggested
we do the experiment anyway.  The teacher rose his voice in arrogance and
tried to make a mockery of me in front of the class and had me stand in
front of everybody while I did the experiment.  To his surprise, the ball
stayed in the funnel due to eddy currents of air.  And I was able to make a
snide remark that made his face turn red.

We should all have questioning minds, but we must all have respect for
others at the same time.  If one of the brightest minds in human history
said capacitance and inductance were variable, we had better prove him wrong
with data and not blow his research away with uninformed opinions.

>There are two issues to be dealt with I think: the first is why capacitance
should increase with height (for an isolated terminal) and secondly, just
how isolated was the terminal in reality? I got the distinct impression that
it was connected to his apparatus by a piece of wire (how else did he
measure it if not?) which is not an isolated situation at all. Anyone who
has gone seriously into measuring properties of Tesla type resonators will
understand the difficulties.

Your thoughts are correct to a certain point.  There was a wire in some
experiments and there was a steel tubed pole in others.  If you have read
the details of these experiments beginning at the end of October and going
all the way through November, you would have known Tesla painstakingly
measured the capacitance of both the steel pole and of the wire and took
this into consideration.  Even the capacitance of the pole was noted to have
changed from day to day.  Tesla was well aware that the capacitance of the
pole amounted to the majority of top load capacitance while measuring the
capacity of the ball, but he was able to factor that into his equations with
a comfortable degree of accuracy.

>Questioning interpretation of some results does not amount to arrogance I
would suggest.

It does if the result of questioning results in a conclusion based solely on
opinion.  If questioning leads to further experiments and the results of the
data repeatedly show error in the original experiment, the questioning leads
to a correction and better opinion.  All Richard did was cast doubt on
Tesla's results by say that he _believed_ Tesla was wrong.   That is not
good scientific journalism.

>Like all human beings (you and I included), Tesla was not without error.

And like all good scientists, you and I should insist on evidence of error
as much as we do on evidence of discovery.  Tesla provided the evidence of
discovery, where is Richard Hull's evidence of error?  I agree Tesla was in
error on a number of things.  For instance, he thought he would live to 120
years, but only made it to 86 (he didn't figure on being hit by a car.)
Tesla also had way too much faith in human progress.  We're nowhere near as
efficient of a society as he envisioned we would be.

>I would be interested to see your explanation of why a truly isolated
terminal should increase its capacitance as it is moved away from the
ground. I have a right to question that which to me does not make sense. So
does everyone else.

Malcolm, you have a right to question only the things that are actually
said.  You cannot question something that was not said.  The article
begins...

"Ever since anything has been known about electricity, scientific men have
taken for granted that the capacity of an electrical conductor is constant.
When Tesla was experimenting in Colorado he found out that this capacity is
not constant - but variable."

The discussion is about the capacity of a conductor, not an isolated
capacity.  The word "isolated" doesn't even appear in that article.

Dave