RE: Two Manifestations of Charge

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

Hello Dave,

On 4 Jul 2005, at 9:29, Tesla list wrote:

> Original poster: "David Thomson" <dwt@xxxxxxxxxxxx>
>
> Hi Malcolm,
>
>  >           Although I haven't replicated your particular
>  > setup, for the fun of it I once replicated a coil described
>  > by Tesla in his lecture to the EE Society of NY (I think it
>  > was - I have the book at home).
>  > The coil was a double-resonant disruptive type but had the
>  > secondary wound in two sections (as described in the book) as
> "lumped"
>  > inductors with a primary in between. I was particularly
>  > interested in this coil because a photo of the original
>  > running with large wire loops run in parallel, each connected
>  > to the hot end of each secondary portion) showed a bundle of
>  > sparks of varying intensities apparently all going at the
>  > same time along the length of the loops.
>
> I happen to have one of Tesla's actual double cone coils from his lab.
>  The secondary is made from two opposing 6" x 6" isosceles cones with
> a primary in the middle.  I'll try that parallel loop setup sometime.
> Can you remember the date of the lecture?  Did he describe the
> geometry of the secondary for that particular setup?

He did. I knew someone would ask so I brought the book in with me for
reference. The lecture was to the NY Academy of Sciences BTW. Date:
April 6th, 1897. The particular lecture is entitled "Improved
Apparatus for the Production of Powerful Electrical Vibrations; Novel
High Frequency Measurement Methods". A bit of a mouthful I have to
say. It starts on p.29 of the book I have, edited by Leland Anderson
and apparently published in 1994. There are two photographs of it
running, one on p.41 and the other on p.52. There is a painfully
complete description of the workings of the machine and the method of
construction (that bit being informative vis-a-vis building it to
survive the HV produced) but I can't find a specific mention of the
number of turns on either coil. At the time I built my model I simply
filled up a couple of solder spools with wire as my secondary,
knowing as I did that any coil will self-resonate at some
frequency(s).
     Not the best bedtime reading if you are tired but in all
fairness, he was describing techniques which were novel in his day.
I think you would be interested in reading this if you haven't
already got it. I found it to be one of his more fascinating works as
it also contains what I suspect are some of the earliest descriptions
of the harmful effects of X-ray (over)exposure following his personal
experiences. The ISBN number is 0-9636012-7-X. The back cover
contains a review by Ken and James Corum.

Malcolm