Meaning of Medhurst K Values?

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

Original poster: "harvey norris by way of Terry Fritz <teslalist-at-qwest-dot-net>" <harvich-at-yahoo-dot-com>

I have understood that a Medhurst chart can be used to
calculate the internal capacity of a solenoidal coil,
by its H/D ratio. I would assume that the internal
capacity of a coil cannot be directly measured by
meter, correct?

A question I have here in this regards, is what does
the value of K indicate?

http://perso.wanadoo.fr/teslacoil/TC20.htm

under the section
MEDHURST self resonant C of Solenoids
shows a chart of K vs H/d.
How do I translate the K of a coil into a value of
internal capacity?
Sincerely HDN