Flat transmission line capacitance formula?

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

Original poster: Bert Pool <bert.tx-at-prodigy-dot-net> 

I have formulae for isolated spheres, toroids, flat plate capacitors, etc., 
but do not have a formula for calculating the capacitance of a single, long 
flat plate transmission line.  I use a long strip of aluminum flashing for 
the transmission line from the driver to the extra coil on my 
magnifier.  Tesla provides us a formula for a cylindrical transmission 
line, but nowhere do I find a formula for a flat plate line.  Does anyone 
out there have such a formula?  I will be conducting some measurements on a 
real-world line to determine the measured capacitance, but it sure would be 
a help if I had a starting formula from which to work!

Thanks,
Bert Pool