1916 Era Quenched Gap

To all spark gap enthusiasts,

Lindsay Publications sells a very interesting republication entitled "High
Frequency Apparatus" by Thomas Stanley Curtis which describes 1916 era TCs
and how to make the various components.  In it is described what he calls a
quenched gap.  He says "The effects produced with the high-frequency coil
in connection with a quenched gap are truly remarkable.  Instead of the
thin, wiry spark ordinarily seen, the discharge takes the form of a flame
as thick as a man's wrist when conditions are right.  At times the actual
length of the discharge is reduced, but with everything in resonance an
increase both of thickness and length will be noted."  He says the sound is
"a loud crashing hiss".

Keep in mind that in 1916, the coils he described in the book only had a
ball an inch or so in diameter as the discharge terminal (no large torroids
or spheres).  I wonder if the flame-like discharges would still occur with
higher capacitance toploads - probably not.  The effect he describes sounds
a lot like VTTC discharges.

What is the quenched gap he speaks of?  His construction examples are 4
inch diameter by an inch or so thick machined castings of solid copper. 
"By making the spark gap electrodes very massive, facing them off very
accurately in a lathe, providing large radiation surface on each electrode,
and, finally, by supporting the electrodes in such a manner that the
separation of their faces is but a few thousandths or perhaps hundredths of
an inch, we have what is commonly termed the quenched gap."  The back sides
of the disks have machined fins to act as heat sinks to help keep the gap

He says "The large surface and the short gap increase the total number of
discharges per (primary transformer) alternation of the current from one or
two per alternation to several hundred or perhaps a thousand".  

Can anyone report the results of modern day experiments with such a
quenched gap?

(By the way, this book has an interesting chapter on growing plants under
an "antenna" connected to a TC, and compares the results against a normal
control group.  10 radishes weighed 79 grams grown normally but 139 grams
grown in the RF field of a 130 watt TC run two hours a day!  My
question--what is going on which would cause such a growth difference? 
Ozone??  Of course, the FCC and OSHA weren't around in those days to shut
down TC enhanced gardens!)